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Dark soils of the Victoria area, British Columbia Broersma, K. 1973

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t l DARK SOILS OF THE VICTORIA AREA, BRITISH COLUMBIA by KLAAS (CLARENCE) BROERSMA B.S. (Agr.), University of B r i t i s h Columbia, 1971 A THESIS SUBMITTED IN PARTIAL FULFILMENT FOR THE DEGREE OF MASTER OF SCIENCE in the Department of Soil Science We accept this thesis as conforming to the required standards THE UNIVERSITY OF BRITISH COLUMBIA November, 1973 In presenting this thesis in p a r t i a l f u l f i l m e n t of the requirements for an advanced degree at the University of B r i t i s h Columbia, I agree that the Library s h a l l make i t fr e e l y available for reference and study. I further agree that permission for extensively copying of t h i s thesis for scholarly purposes may be granted by the Head of my Department or by his representatives. I t i s understood that copying or duplication of t h i s thesis for f i n a n c i a l gain s h a l l not be allowed without my written permission. Department of S o i l Science The University of B r i t i s h Columbia Vancouver 8, Canada i i ABSTRACT Seven soi ls with deep surface horizons high in organic matter occurring in south-eastern Vancouver Island in an unique environment were elucidated. The climate is similar to that of the northern Mediterranean. The vegetation consists of a grass and Garry oak (Querous gavvyana) parkland on the more xeric s i tes . This vegetation is believed to be part of a biosequence of grass, Garry oak and Douglas f i r {Psuedotsuga menziesii). Four s i tes were located under vegetation consisting of grass and scattered Garry oak, two sites under Garry oak and one under Douglas f i r . In the f i r s t paper, Dark Soils of the Victor ia Area, Vancouver Island I Environment, Morphology and Genesis, the soi ls and the environment are described. A l l the soi ls were c lass i f ied into the Canadian and American Systems of Soil C lass i f icat ion . The soi ls were a l l c lass i f ied as Sombric Brunisols except for the one under Douglas f i r which was c lass i f ied as a Sombric Podzol according to the Canadian System of Soil C lass i f icat ion . In the second paper, Dark Soils of the Victoria Area, Vancouver Island, II Physical , Chemical, Mineralogical Properties and Genesis, the results of the physical, chemical and mineralogical analysis are discussed. The soi ls are coarse textured and are a l l characterized by high amounts of organic matter in the surface horizon. The organic matter has an influence on many of the so i l properties. Most weathering in these soi ls occurs in the surface horizons. i i i In the third paper. Natural Organo-Mineral Complexes in Some Sombric Soils of the Victoria Area, Vancouver Island, the natural complexes of surface horizons were separated and studied. The separates in this study included: coarse s i l t (50-20M), fine s i l t (20-2u), coarse clay (2-0.2y) and fine clay (<0.2y). Most of the soils organic matter was found to be associated with the fine s i l t and coarse clay fractions. The amount of organic matter per centimeter square in the coarse and fine clay was found to be nearly constant. The finer fractions were associated with the more humified organic matter. The importance of the binding or bridging cations were found to be in the order: A l , Ca, Fe, Mn, Cu, Zn = Mg in these soils. iv ACKNOWLEDGEMENTS The author wishes to express his thankfulness to Dr. L.M. Lavku l i ch , Associate Professor , Department of So i l Science for supervision and assistance with t h i s study and the preparation of the t h e s i s . Gratitude i s p a r t i c u l a r l y expressed to Mr. Alex Green, Pedologist at Canada Department of A g r i c u l t u r e , Research S t a t i o n , Vancouver, for the help with the f i e l d work of c o l l e c t i n g and descr ib -ing the s o i l s used for th is study. Appreciat ion is also expressed to Mr. Bernie von Sp ind ler , Miss Sh ie la McMeekin and Miss L e s l i e Simpson for the i r assistance in the laboratory and to Mark Wamsley for assistance with computer programming. The author also wishes to thank a l l other fe l low students and technicians who helped make the laboratory' a happier place to work by t h e i r f r i end l iness and laughter. Thanks are also due to the other members on my graduate committee which included Dr. L .E . Lowe, Associate Professor , Department of S o i l Science, Dr. C.A. Rowles, Professor and Chairman of the Department of S o i l Science; and Dr. N. Keser, Research D i v i s i o n , B r i t i s h Columbia Forest Serv ice . Thanks are expressed to Dr. G.W. Eaton, Department of Plant Science, fo r use of his microscope and camera. V The author i s grateful to Miss Beth Loughran for the draught-ing of the figures for this thesis. Special thanks are extended to the author's wife, Jenny, for help i n the laboratory and with the preparation of the thesis but mostly for her understanding and care during the graduate program. v i TABLE OF CONTENTS Section Page INTRODUCTION 1 I. ENVIRONMENT, MORPHOLOGY AND GENESIS 2 ABSTRACT 2 INTRODUCTION . 3 ENVIRONMENTAL ELEMENTS OF THE STUDY AREA 6 Physiography 6 Geology 6 Climate 7 Vegetation 7 DESCRIPTION OF THE SITES 12 Site 1 12» S i t e 2 16 Site 3 16 Site 4 18 S i t e 5 i g Site 6 . . 22 Site 7 23 RESULTS AND DISCUSSION . . . 26 CONCLUSIONS . 3 4 LITERATURE CITED 36 v i i Section Page I I . PHYSICAL, CHEMICAL, MINERALOGICAL PROPERTIES AND GENESIS 38 ABSTRACT . . . . . . 38 INTRODUCTION 39 METHODS AND MATERIALS 39 Sample Preparation 39 Physical Analysis 40 Chemical Analysis 40 Mineralogical Analysis 41 RESULTS AND DISCUSSION 42 Physical Analysis 42 Chemical Analysis 45 Mineralogical Analysis . . . . 64 Genesis of the Sombric So i l s 68 LITERATURE CITED 71 I I I . NATURAL ORGANO-MINERAL COMPLEXES IN SOME SOMBRIC SOILS OF SOUTH-EASTERN VANCOUVER ISLAND 7 4 ABSTRACT . . . 74 INTRODUCTION . 75 MATERIALS AND METHODS .- . 77 Description of Sites 77 Methods Used 79 Results and Discussion 82 CONCLUSIONS . 102 LITERATURE CITED ~. 105 SUMMARY 109 v i i i LIST OF TABLES Table Page SECTION I 1. Selected Meteorological Data for South-Eastern Vancouver Island . . ' 8 2. Organic Matter, Pyrophosphate and Oxalate Extrac-table Fe and Al -and Humic to Fulvic Acid Ratio 29 3. C l a s s i f i c a t i o n of the S o i l s into the Canadian and American Systems of S o i l C l a s s i f i c a t i o n .. . 32 SECTION II 1. Selected Physical Properties of the S o i l s 43 2. Reaction and Exchange Properties of the Soils . . . . . . . 46 3. Selected Chemical Properties of the Soils 50 4. pH Dependent Cation Exchange Capacity of the S o i l s . . . . 55 5. Extractable Iron and Aluminum and Calculated Iron Oxides 58 6. Elemental Analysis of the <2 mm So i l 62 7. Mineralogy of the Clay and S i l t Fractions of the S o i l s 65 SECTION I I I 1. D i s t r i b u t i o n of Organo-Mineral Complexes and Organic Matter 84 2. Surface Area of Inorganic Separates and the Quantity of Organic Matter Distributed per cm2 of Surface Area 87 3. Total Carbon, Total Nitrogen and the C/N Ratio for Complexes and Whole S o i l . 91 4. Exchangeable Cations of the Complexes and the Whole S o i l 94 ix Table Page 5. Amounts of Binding and Bridging Cations 98 6. Sodium Pyrophosphate Extraction of A l , Fe, Ca, Mg and Mn 101 4 X LIST OF FIGURES Figure Page SECTION I 1. Vancouver Island 4 2. Garry oak {Queraus garvyana) with grass and broom understory and scattered Douglas f i r (Psuedotsuga menziesii) 9 3. Sampling s i t e s and meteorological stations . . . . 11 4a. Vegetation at s i t e 1 14 4b. S o i l p r o f i l e of s i t e 1 15 5. Vegetation and s o i l p r o f i l e of s i t e 2 . . 17 6a. Vegetation at s i t e 5 20 6b. S o i l p r o f i l e of s i t e 5 . . . • 21 7a. Vegetation at s i t e 7 24 7b. S o i l p r o f i l e of s i t e 7 25 SECTION III 1. Comparison of U.S.D.A. and International s i z e fractions to those used for the organo-mineral study 80 2a. Presence of free organic matter in the f i n e s i l t of s i t e 7 88 2b. Granulation of the f i n e clay due to freeze drying ftq INTRODUCTION The Sombric s o i l s of south-eastern Vancouver Island have been of interest since they were c l a s s i f i e d f i r s t by Day et a l . [1959] as Black and Acid Dark Brown Forest S o i l s , according to the old Canadian S o i l C l a s s i f i c a t i o n System. These s o i l s are found in an unique environment. The climate i s very s i m i l a r to that of the northern Mediterranean. The vegetation consisted of various mixtures of grass, Garry oak (Quereus gavvyana) and Douglas f i r {Psuedostuga menziesii). The resulting s o i l s have high amounts of organic matter in the surface horizons with weakly developed B horizons. The environment is very pleasant and favourable as can be seen from the fact that most of the population of Vancouver Island i s found on the south-east side. This has resulted in large areas being d i s -turbed by man's a c t i v i t i e s and only leaving a few small natural areas. Since l i t t l e was known as to the properties and genesis of these s o i l s a detailed study was undertaken. The study consisted of: part one, the environment, morphology and genesis; part two, selected physical, chemical, mineralogical properties and genesis; and part three, the relationship of the organic matter and inorganic matter through studying the s o i l ' s organo-mineral complexes in the surface horizons. 2 I. ENVIRONMENT, MORPHOLOGY AND GENESIS ABSTRACT In the south-eastern portion of Vancouver Island are found s o i l s that are "chernozemic" i n t h e i r morphology. These s o i l s are associated with a vegetation consisting of Garry oak [Quevcus garryana) and various kinds of shrubs and grasses. The climate i s Mediterranean which i s characterized by an average annual p r e c i p i t a t i o n of 800 mm. Less than 40 mm f a l l s during July and August. The vegetation i s thought to be part of a biosequence of grass, grass and Garry oak, Garry oak and Douglas f i r {Psuedostuga menziesii). The environment, morphology and genesis of these s o i l s are discussed and elucidated. 3 INTRODUCTION The s o i l s associated with Garry oak (Quevcus garryana) and grasses represents an unique environment that has not been studied to any large degree from a s o i l s point of view in B r i t i s h Columbia. This type of environment is not found anywhere else in the world at such a high l a t i t u d e . In B r i t i s h Columbia these s o i l s are found on the south-eastern coast of Vancouver Island and on the Gulf Island (Figure 1). These s o i l s were f i r s t described i n Day et a l . • 959] and were at that time c l a s s i f i e d into either the Acid Dark Brown Forest or the Black great groups [C.S.S.C. 1959]. The Willamette Valley in Oregon [Thilenius, 1964] and in the southern Puget Sound area of Washington [Ugolini and Schlichte, 1973] have s i m i l a r s o i l s . These s o i l s are also considered to be s i m i l a r to the Andeptsof the Aleutians, Alaska, in morphology according to Simonson and Rieger [1967]. These l a t t e r s o i l s have def i n i t e additions of volcanic ash, whereas the s o i l s of Vancouver Island are believed not to be so affected. Limited studied on the s o i l s have been conducted by Clark et a l . [1967] and Roemer [1972]. Day et al_. [1959] report on the general d i s t r i b u t i o n of these s o i l s on Vancouver Island and the Gulf Islands with some preliminary data on th e i r properties. The Black great s o i l group i s characterized by a deep Ah horizon that i s dark brown to black in colour with a s l i g h t l y granular structure. The B horizon i s dark brown in colour. The associated vegetation consists of Garry oak and grasses with, scattered Douglas f i r . Figure 1 Vancouver Island, B.C. and the study area 5 Although both s o i l great groups, Acid Dark Brown Forest and Black, are very s i m i l a r , there i s more pedogenic development i n the Acid Dark Brown Forest. According to the newer c l a s s i f i c a t i o n s the Acid Dark Brown Forest great group would be equivalent to the Sombric Podzol, while the Black great group would be more s i m i l a r to Sombric Brunisols. Studies within t h i s environment are very d i f f i c u l t since most of the area i s situated i n the most densely populated area of Vancouver Island. Also with the increased in t e n s i t y of land use, most of the area has been disturbed. The favourable climate plays an impor-tant role i n at t r a c t i n g people to the area. Since the environment or external factors are important i n the characterization and development of s o i l s [Crowther, 1953], a study considering these factors would help in the elucidation of these s o i l s . Environmental factors therefore can be considered to set l i m i t s and di r e c t i o n for s o i l development [Buol et^ al_., 1973]. The purpose of this study was to investigate the morphology and genesis of these s o i l s i n r e l a t i o n to the environmental factors, especially climate and vegetation. The area can be considered as a tension zone between the d i f f e r e n t plant communities consisting of a biosequence of grasses, grasses and Garry oak, Garry oak and Douglas f i r , and Douglas f i r . A d e f i n i t e correlation should e x i s t between the s o i l s and the vegetation. Also an attempt i s made to c l a s s i f y these s o i l s according to the Canadian and American systems of s o i l c l a s s i f i c a t i o n . 6 Environmental Elements of the Study Area Physiography The study area is located at the southern tip of Vancouver Island in the vicinity of Victoria. This area is part of the Nanaimo Lowland which extends from Sayward along the east coast to Jordan River, west of Victoria, as a narrow Coastal Plain. This forms part of the Coastal Trough which is flanked on the west by the Insular Mountains, that dominate Vancouver Island, and on the east by the Coastal Mountains [Holland, 1964]. Geology Except for the highest peaks all of Vancouver Island was glaciated during the Pleistocene. The major glaciations were during the Fraser Glaciation (25,000 - 10,000 years B.P.) and consisted of the Vashon and Sumus stades which were part of the Late Wisconsin stage [Ryder, 1972]. This glacial event left a gravelly glacial t i l l over most of the Island. The land under the heavy ice subsided raising the sea level in relation to the land by an average of over 30 meters. Raised beaches are in evidence in the vicinity of Victoria [Newcombe, 1914] due to the rebound of the land upon glacial retreat. This resulted in a considerable amount of sorted materials along the Coastal Plain. In the Victoria area the lowland is underlain by granitic and volcanic rock [Clapp, 1914] which are rather resistant to erosion. This resistance is evident by the numberous hil ls in this area. 7 CIimate Vancouver Island i s influenced by a maritime climate that i s characterized by warm, dry summers and mild, wet winters. In the study area the summer and the winters- are much d r i e r and warmer due to the rain-shadow ef f e c t of the Insular and Olympic Mountains. Except for the cooler summer temperatures, the climate of the study area i s si m i l a r to that of the Northern Mediterranean region. This area represents the farthest poleward advance of a "true" Mediterranean climate on the earth's surface [Kerr, 1951]. The mean annual temperature i s 10°C while the mean annual p r e c i p i t a t i o n i s about 800 mm of which less than 40 mm or 5% i s received during July and August (Table 1). The summer drought i s severe in that s o i l moisture d e f i c i e n c i e s for plants of 11 inches per growing season are normal [Farstad et al_., 1959]. Vegetation The vegetation associated with these black s o i l s i s predominantly composed of a forest-grassland association or parkland of Garry oak [Queraus• garryana) and Douglas f i r {Psuedotsuga menziesii) with Arbutus [Arbutus menziesii) .on the most xeric and exposed s i t e s (see Figure 2). The understory consists of shrubs and grasses. This type of vegetation i s c h a r a c t e r i s t i c of a cool Mediterranean climate. Garry oak occurs i n B r i t i s h Columbia only on the south-eastern coast of Vancouver Island and the Gulf Islands to a limited extent [Krajina, 1969] i n B r i t i s h Columbia. The farthest north-ward TABLE 1 Selected Meteorological Data for South-eastern Vancouver Island TEMPERATURE TOTAL PRECIPITATION Station Mean Annual Mean Mean Annual Mean Mean June-Sept July-Aug June-Sept July-Aug °C °C °C mm mm mm Vi c t o r i a (Gonzales Obs.) 10.0 14.9 15.6 695 91 33 Cordova Bay 10.0 15.3 16.4 849 109 37 Elk Lake 10.0 15.8 16.9 931 131 44 Saanichton (CD.A.) 9.4 15.3 16.4 838 113 44 Salt Spring Is. (Ganges) 10.0 17.5 16.0 1012 128 48 Figure 2 Garry oak {Quevcus gavvyana) with grass and broom understory and scattered Douglas f i r {Psuedotsuga menziesii) extention of this vegetation i s Courtenay (Figure 1). Two small groves are situated on the mainland, one at Yale and the other on Sumas Mountain [Lyons, 1952]. These groves are thought to have been i n t r o -duced by Indians. Broom [Cytisus scoparius) which i s prominent due to i t s b r i l l i a n t yellow bloom throughout Vancouver Island i s not native. I t i s believed to have been introduced by an early English s e t t l e r . Broom i s found mainly on dry slopes, rocky knolls and road edges and suppresses the e f f o r t s of many native plants [Lyons, 1952]. Garry oak and i t s associated vegetation mainly inhabits the xe r i c s i t e s such as,' h i l l tops and shallow, gravelly s o i l s . This type of vegetation has i t s center of population i n Oregon's Willamette Valley from where i t extends north through the Puget Sound Basin to Vancouver Island and south into Northern C a l i f o r n i a [Rowe, 1959; Franklin and Dyrness,1969]. Successional trends i n the same type of vegetation i n the-Willamette Valley of Oregon [Sprague and Hansen, 1946] are thought to • be occurring here. These authors observed that non-forested areas are invaded by Garry oak whose shade in turn allows the regeneration of Douglas f i r . The Douglas f i r i s thought to be a serai stage which i s followed by a climax of Grand fir {Abis grandis) or a Douglas f i r -Grand f i r association [Franklin and Dyrness, 1969]. The successional trend was controlled f o r many centuries by - f i r e both anthropic and natural [Thilenius 1964, 1968; Sprague and Hansen, 1946; Habeck, 1961]. The Indians are known to have had a practice of burning to encourage deer to frequent these parts and also Figure 3 Sampling site s and meteorological stations 12 to promote grasshoppers, which they used for winter food. Fires were eas i l y set since the climate and vegetation are very conductive to f i r e due to the cool moist winter and spring allowing the growth of a dense herbaceous ground cover which i s dessiccated during the summer drought. This f i r e pattern was interrupted by settlement of these areas c o n t r o l l i n g the f i r e frequency. The control of f i r e s ameliorates the environmental extremes through the development of a closed-canopy oak fo r e s t , thus allowing plants unable to endure the extreme climatic conditions to establish under t h i s canopy. Douglas f i r i s one species that can regenerate under Garry oak vegetation and eventually grows and forms i t s own closed canopy thus suppressing the Garry oak which i s shade intolerant [Owen, 1953; Krajina, 1969]. Since Douglas f i r cannot regenerate in very strongly shaded areas i t f a i l s to establish under i t s own closed-canopy and promotes the establishment of Grand f i r which i s considered to be the f i n a l stage of the succession [Franklin and Dyrness, 1969]. DESCRIPTION OF THE SITES The sampling s i t e s are shown in Figure 3 in r e l a t i o n to the general geography of the area. Site 1 The s i t e was located i n Cenotaph Park inside the Uplands entrance on Beach Drive, V i c t o r i a . The area has a gentle slope of about 2% at the s i t e with a south aspect at about 20 meters above sea l e v e l . The parent material consists of about one meter of marine sand and gravel overlying g l a c i a l marine material. The bed-rock consists of Metchosin volcanics, which were evident as rock outcrops. This s o i l i s well drained and rapidly permeable above the marine materials. The vegetation of the s i t e consisted of dryland 13 sedges (Carix spp.) and narrow leaf plantain {Plantago maritima). The s i t e was surrounded by Broom {Cytisus sooparius) and Garry oak (Figure 4a). Horizon Depth(cm) P r o f i l e Description Ah 1 0--15 Black (7.5YR 2/0 m, 10YR 3/1 d) sandy loam; weak, medium granular; very friable;abundant fine roots; dark organic coating on pebbles, scattered clean quartz grains; 15 percent coarse fragments; gradual boundary; pH 4.6 (0.01 M CaCl 2) Ah 2 15-•28 Black (7.5YR 2/0 m, 10YR 3/2 d) gravelly sandy loam; weak, fine granular;very f r i a b l e ; abundant fine roots; dark organic coating on pebbles, scattered clean quartz grains; 20 percent coarse fragments; cl e a r , wavy boundary; pH 4.6 (0.01 M-CaCl2) Bm 28--38 Dark brown (10YR 3/3 m, 10YR 5/4 d) gravelly loamy sand; weak, medium subangular blocky; very f r i a b l e ; abundant fine roots, very few medium roots; thin brown coating on pebbles; 20 percent coarse frag-ments; abrupt undulating boundary; pH 4.8 (0.01 M CaCl 2) Cl 38-•64 Brown (10YR 5/3 m, 10YR 6/3 d) medium sand; single grain; loose; few fine roots; r e l a t i v e l y clean " grains of medium sand; 15 percent coarse fragments; clear boundary; pH 5.2 (0.01 M CaCl 2) C2 64-•76 Light o l i v e brown (2.5Y 5/4 m, 10YR 6/4 d) g r a v e l l y sand; single grain; loose; very few fine and few medium roots; r e l a t i v e l y clean grains of medium sand; 25 percent coarse fragments; clea r , wavy boundary; pH 5.2 (0.01 M CaCl 2) IIC1 76- 94 Greenish Gray (5GY 5/1 m, 2.5Y 6/2 d) s i l t y clay; common, fine d i s t i n c t yellowish brown mottles; moderate, medium subangular blocky; f i r m ; very few fine and medium roots; thin clay f i l m on ped faces; 15 percent coarse fragments; gradual boundary; pH 4.9 (0.01 M CaCl 2) IIC2 94- 122 Greenish Gray (5GY 5/1 m, 5Y 6/2 d) clay; few, fine f a i n t mottles; strong, coarse angular blocky breaking to strong fine angular blocky; very firm; no roots; manganese staining and thin clay coating on some ped faces and cleavage planes; 5 percent coarse fragments; pH 5.1 (0.01 M CaCl 2). 14 Figure 4a Vegetation at s i t e 1 15 Figure 4b Soil p r o f i l e of s i t e 1 16 Site 2 This s i t e was located on the south side of McKenzie street at i t s junction with Cedar H i l l Cross Road, V i c t o r i a . The area has a moderate slope with the s i t e located at the top of the slope. The parent material consists of shallow sandy loam t i l l over a bedrock of igneous rock. The s o i l i s well drained and rapidly permeable to bedrock. The s i t e i s located under a moderately dense cover of grasses, vetch and some mosses (Figure 5). Broom and Garry oak are i n the general v i c i n i t y . Horizon Depth(cm) P r o f i l e Description Ah 0-20 Very dark gray (10YR 3/1 m, 10YR 2/2 d) fine sandy loam; moderate, coarse granular breaking to moderate, medium and fine granular; very f r i a b l e , s oft when dry; abundant fine roots; thin dark organic coating on angular rocks; 5 percent coarse fragments, abrupt boundary; pH 4.1 (0.01 M CaCl 2) R 20 + Igneous bedrock. Site 3 This s i t e was located about 15 meters south of s i t e 2 on deeper parent material. The parent material and vegetation were very s i m i l a r to that found at s i t e 2. The s o i l i s very well drained and rapidly permeable to about 36 cm. Run-off i s very low. Horizon Depth(cm) P r o f i l e Description Ah 1 0-10 Very dark grayish brown (10YR 3/2 m, 10YR 3/3 d) very f i n e sandy loam; very weak fine granular; very f r i a b l e , soft when dry; abundant fine roots forming a mat; dark brown organic coating on the pebbles; 10 percent coarse fragments (mainly angular but some rounded); diffuse boundary; pH 4.2 (0.01 M CaCl 2) Ah 2 10-15 Very dark grayish brown (10YR 3/2 m, 10YR 3/3 d) very f i n e sandy loam; weak medium and fine granular; very f r i a b l e , soft when dry; abundant fine and common medium roots; dark brown organic coating on pebbles; 15 percent coarse fragments; clear boundary; pH 4.3 (0.01 M CaCl 2) 18 Horizon Depth(cm) P r o f i l e Description Bm 15-30 Yellowish brown (10YR 5/4 m, 10YR 5/3 d) fine sandy loam; weak, medium subangular blocky breaking to weak, medium granular; very f r i a b l e , s oft when dry; p l e n t i f u l fine and few medium roots; very thin f i l m of fine materials on rocks; 10 percent coarse fragments; clear boundary; pH 4.3 (0.01 M CaCl 2) Bh 30-36 Dark brown to brown (10YR 4/3 m, 10YR 4/3 d) sandy loam; weak, medium subangular blocky; very f r i a b l e , soft when dry; many fine and few medium roots; moderately thick f i l m of fine materials on rocks; 10 percent coarse fragments; abrupt boundary; pH 4.3 (0.01 M CaCl 2) R 36 + Igneous bedrock. Site 4 This s i t e was located at the corner of Cook and Finlayson Streets, V i c t o r i a . The slope i s moderate and the s i t e i s located about 80 meters above sea l e v e l . The parent material consists of coarse textured marine materials over a sandy loam g l a c i a l t i l l . Black fine grained basalt l i e s close to the surface. The s i t e i s located i n an area of grasses and broom with Garry oak 12-15 meters in height i n the immediate v i c i n i t y . S o i l i s moderately well drained with rapid permea-b i l i t y to about 33 cm below which the permeability i s slow. Horizon Depth(cm) P r o f i l e Description Ah 1 0-10 Very dark brown (10YR 2/2 m, 10YR 3/2 d) very fine sandy loam; weak, fine granular; very f r i a b l e , s oft when dry; abundant fine and medium roots forming a mat; dark brown organic coating on the rocks; 15 percent coarse fragments with many angular pebbles; clear boundary; pH 3.9 (0.01 M CaCl 2) Ah 2 10-20 Very dark grayish brown (10YR 3/2 m 3/3 d) very fine sandy loam; f r i a b l e ; strong, very coarse granular breaking to strong, fine granular; abundant fine and few medium roots; dark brown organic coating on the rocks but not as thick as horizon above; 15 percent coarse fragments with many angular pebbles; clear boundary; pH 4.3 (0.01 M CaCl 2) 19 Horizon Depth(cm) P r o f i l e Description Bm 20-33 Dark brown (10YR 4/3 m, 10YR 5/4 d) gravelly sandy loam; medium subangular blocky breaking to weak, fine granular; f r i a b l e ; p l e n t i f u l fine and few medium roots; thin brown coating on the rocks; 20 percent coarse fragments; abrupt boundary; pH 4.4 (0.01 M CaCl 2) Cgj 33-61 Yellowish brown (10YR 5/4 m, 2.5Y 5/4) loamy sandy; common, fine d i s t i n c t mottles; strong, medium angular blocky; hard when dry; very few large roots; thin clay f i l m around pebbles; 15 percent coarse fragments; diffuse boundary; pH 4.4 (0.01 M CaCl 2) C 61-104 Brown (10YR 5/3 m, 5Y 6/3 d) gravelly sandy loam; few, f i n e , f a i n t mottles; strong medium angular blocky; hard when dry; very few large roots; thin clay f i l m around pebbles plus some clean mineral grains; 20 percent coarse fragments, abrupt boundary; - pH 4.4 (0.01 M CaCl 2) R 104 + Black, fine grained volcanic bedrock. Site 5 This s i t e was located very close to s i t e 1 under Garry oak vegetation. Parent materials and bedrock are the same as s i t e 1. The vegetation consists mainly of Garry oak 7-10 meters i n height with some small aspen (Populus tremuloides). The understory i s dense snow berry {Symphoricarpos albus). Also present was wild rose [Rosa spp.), honeysuckle (Lonicera ciliosa) and some grasses (Figures 6a and 6b). Earthworm a c t i v i t y was observed. Horizon Depth (cm) P r o f i l e Description Ah 1 0-18 Black (7.5YR 2/0 m, 10YR 3/1 d) loam weak, fine granular; very f r i a b l e ; abundant fine and medium roots; dark organic coating on pebbles; scattered clean quartz grains; 15 percent coarse fragments; diffuse boundary; pH 4.8 (0.01 M CaCl 2) Ah 2 18-36 Very dark gray (7.5YR 3/0 m, 10YR 3/1 d) gravelly sandy loam; weak medium and fi n e granular; very f r i a b l e ; abundant fine and medium roots; dark organic coating on pebbles but not as thick as in horizon above; scattered clean, quartz grains; 25 percent coarse fragments; clear boundary; pH 4.6 (0.01 M CaCl 2) 20 i Figure 6a Vegetation at s i t e 5 21 Figure 6b Soil p r o f i l e of s i t e 5 22 Horizon Depth (cm) P r o f i l e Description Bm 35-51 Brown (10YR 4/3 m, 10YR 6/2 d) gravelly loamy sand; weak medium subangular blocky breaking to weak, coarse granular; very f r i a b l e ; few fine and medium roots; pebbles are r e l a t i v e l y clean; 20 percent coarse fragments; clear boundary; pH 4.8 (0.01 M CaCl 2) IIC 1 36-99 Gray (5Y 5/1 m, 10YR 6/4 d) s i l t y clay; many, fine prominent yellowish brown mottles, moderate, coarse angular blocky; firm; very few fine and few medium roots; thin clay films on cleavage planes less than 1 percent coarse fragments; gradual boundary; pH 4.7 (0.01 M CaCl 2) IIC 2 99 + Gray (5Y 5/1 m, 2.5Y 6/2 d) s i l t y clay; common, f i n e , f a i n t yellowish brown mottles; moderately coarse angular blocky breaking to strong fine angular blocky, f r i a b l e ; no roots; thin clay films on cleavage faces but no manganese sta i n i n g ; no coarse fragments; pH 5.0 (0.01 M CaCl 2). Site 6 This s i t e was located at Beaconhill Park Lookout, approximately 50 meters north-east of the f l a g pole, in V i c t o r i a . The area i s strongly sloping and about 70 meters above sea l e v e l . The parent material consists of over a meter and a half of marine sands and gravels over a bedrock of Metchosin volcanics. The s i t e was located i n a dense stand of Garry oak 7-10 meters in height. The understory consisted of snow-berry about 2 meters i n height. Broom surrounded the stand. The s o i l i s rapidly drained with very rapid permeability. Earth worms were abundant at this s i t e . Horizon Depth (cm) P r o f i l e Description Ah 1 0-10 Black (10YR 2/1 m, 10YR 2/2 d) loam; strong, medium granular; f r i a b l e ; abundant fine and medium roots; dark brown organic coating on rocks; less than 5 percent coarse fragments; gradual boundary; pH 4.3 (0.01 M CaCl 2) Ah 2 10-23 Very dark brown (10YR 2/2 m, 10YR 3/2 d) sandy loam; strong, fine granular; f r i a b l e ; common fine and abundant medium roots; fine concretions; dark brown organic coating on the rocks; less than 5 percent coarse fragments; gradual boundary; pH 4.2 (0.01 M CaCl 2) 23 Horizon Depth (cm) P r o f i l e Description Ah 3 23-33 Dark brown (10YR 3/3 m, 10YR 3/3 d) loam; moderate medium granular; very f r i a b l e ; common fine and abundant medium roots; fine concretions; thin organic coating on the rocks; 5 percent coarse fragments; clear boundary; pH 4.4 (0.01 M CaCl 2) Bm 33-58 Dark yellowish brown (10YR 3/4 m, 10YR 5/4 d) gravelly sandy loam; weak, medium subangular blocky breaking to fine weak granular; very f r i a b l e ; p l e n t i f u l medium roots; thin brown mineral coating on pebbles; 20 percent coarse fragments; clear boundary; pH 4.5 (0.01 M CaCl 2) BC 58-91 Dark yellowish brown (10YR 4/4 m, 10YR 5/3 d) gravelly sand; single grain; loose; few medium roots; thin brown mineral coating on pebbles; 40 percent coarse fragments; abrupt boundary; pH 4.7 (0.01 M CaCl 2) C 91 Grayish brown (10YR 5/2 m, 5Y 6/2 d) gravelly sand; single grain; loose; clean sand grains; more than 40 percent coarse fragments; pH 5.0 (0.01 M CaCl 2). Site 7 This s i t e was located on the south side of Mount Douglas Park, V i c t o r i a . The area i s steeply sloping with an east aspect about 90 meters above sea l e v e l . The parent material consists of about 65 cm of sandy loamy t i l l over bedrock consisting of Metchosin volcanics. The vegetation consisted mainly of Douglas f i r , 30-40 meters high. Broadleaf maple {Acer macrophyllum) was present. The understory consisted of a low sparse shrub of Oregon grape (Berberis aquifolium), huckleberry [Vaccinium ovatwn) bracken fern {Ptendium aquilinwn pubescens) and sword fern [Polystichwn munition) (Figure 7a and 7b). Horizon Depth (cm) P r o f i l e Description Ah 0-10 Very dark grayish brown (10YR 3/2 m, 10YR 4/2 d) loam; strong, medium and coarse granular; f r i a b l e ; abundant fine and medium roots; very s l i g h t organic coating on pebbles; less than 5 percent coarse frag-ments; abrupt boundary; pH 4.3 (0.01 M CaCl 2) Figure 7a Vegetation at s i t e 7 2 5 Figure 7b S o i l p r o f i l e of s i t e 7 26 Hori zon Depth (cm) P r o f i l e Description Bf 10-38 Brown to dark brown (7.5YR 4/4 m, 10YR 5/5 d) sandy loam; weak coarse subangular blocky breaking to weak medium and fine granular; very f r i a b l e ; p l e n t i f u l fine and medium roots; thin brown mineral coating on pebbles; 10 percent coarse fragments; gradual boundary; pH 4.8 (0.01 M CaCl 2) Bm 38-66 Dark yellowish brown (10YR 4/4 m, 10YR 5/4 d) sandy loam; weak fine granular; very f r i a b l e ; p l e n t i f u l f i n e and medium roots; thin brown mineral coating on pebbles; 15 percent coarse fragments; abrupt boundary; pH 4.6 (0.01 M CaCl 2) R 66 + Igneous bedrock. RESULTS AND DISCUSSION Elucidation of the morphology of these s o i l s requires evaluation of the overall p h y s i c a l , chemical and b i o l o g i c a l properties that make up the whole s o i l . These properties that make up the whole s o i l are expressed d i f f e r e n t l y i n each s o i l , as well as, i n each s o i l horizon. These characterizations can be obtained from the observations and measurements of properties such as horizons, depth of horizon, colour, texture, structure, consistence and pH. The morphology expressed by these s o i l s at each s i t e can be compared and contrasted i n order to study the genesis of these s o i l s . The comparing and contrasting was done on a very general basis of three d i s t i n c t i v e type of s i t e s . Sites 1 to 4 were considered as the grass and grass-Garry oak s o i l s , s i t e s 5 and 6 as the Garry oak forested s o i l s and s i t e 7 was considered as the Douglas f i r forested s o i l . 27 So i l colour i s probably the most s t r i k i n g feature of these s o i l s . The dark brown to black colours of the surface horizons are in d i c a t i v e of the high amounts of organic matter present i n these s o i l s . F i e l d observations show that there i s a s l i g h t browning of the surface horizon as one proceeds from grass to Garry oak to Douglas f i r . The s l i g h t colour differences could be attributed to the d i f f e r e n t humic substances present at these s i t e s . This could be the r e s u l t of the two d i f f e r e n t organic acids observed by Springer i n d i f f e r e n t s o i l environ-ments [Kononova, 1961]. The f i r s t type i s the f u l v i c acid or "brown humic acids" which i s c h a r a c t e r i s t i c of podzolic type of s o i l s . The second type i s the humic acid or "gray humic acids" which i s characteris-t i c of the chernozemic s o i l s . This trend can be observed in Table 2 where i t can be seen that the s i t e s 1, 2, and 4 are much higher in humic acid than f u l v i c acids as i s indicated by the high humic acid to f u l v i c acid ratios of 3 and over. S i t e 7 has the lowest r a t i o of 1.4 while s i t e 5 and 6 have ratios of 2 to 3 indicating intermediate humic acid to f u l v i c acid r a t i o s . The depth of the surface horizon i s di f f e r e n t f o r each of the three d i s t i n c t i v e s i t e s . The grass s i t e s have a moderately deep surface horizon of about 25 cm, while the Garry oak sites have a deep surface horizon of about 30 cm. The deeper surface horizon of the Garry oak s i t e can be attributed to a greater t o t a l l i t t e r f a l l , rapid decomposition due to substantial organism a c t i v i t y because of the less severe drought conditions to a s s i s t decomposition. The Douglas f i r s i t e has a very shallow surface horizon due to the nature of the forest f l o o r composition and slow decomposition. The Douglas f i r material with i t s wide C/N 28 r a t i o (50 or more) decomposes much more slowly than the organic materials from Garry oak with a C/N r a t i o of 20-50, and the grasses with a C/N r a t i o of 10-20 [Cruickshank, 1972]. The colour of the B horizon i s important for the observation of translocated and transformed materials such as oxides of aluminum and i r o n , organic matter, clays and s a l t s . The chromas observed in the Douglas f i r s i t e were higher than those of the other s i t e s . Also observed at nearly a l l s i t e s was a brown staining of the coarser fragments in the B horizon which was due to organic matter and sesquioxides. The structure and consistence of the s o i l s at the Garry oak and Douglas f i r s i t e s was much better than i n the grass s i t e s . The well developed structure associated with Garry oak could be due to some degree by the earth worm a c t i v i t y which was observed at both Garry oak s i t e s . S i t e 6 especially had many earth warm casts on the s o i l surface. The structure i n the Douglas f i r s i t e on the other hand, could be an inherent structure from previous s o i l forming factors such as a Garry oak vegetation and i t s associated fauna. I t i s d i f f i c u l t to compare the d i f f e r e n t s i t e s on a basis of texture because of var i a t i o n i n the parent material. A l l s o i l pedons show an increase in the percentage of coarse fragment with depth. The coarse fragments make up a considerable portion of the s o i l ' s t o t a l volume. The texture of the surface horizon becomes progressively f i n e r from the grass-Garry oak, to the Garry oak, to the Douglas f i r s i t e . The pH of a l l the s o i l s f a l l between 4 and 5 (0.01 M CaCl 2). This indicates that there i s some degree of leaching since the s o i l s are strongly a c i d i c . The cause of t h i s a c i d i t y i s due to a large TABLE 2 Organic Matter, Pyrophosphate and Oxalate Extractable Fe and A l , and Humic-Fulvic Acid Ratios Horizon Depth O.M. Na Pyrophosphate NH4 Oxalate Ch Cf Ch/Cf cm % Fe % Al % Fe % Al % % % SITE 1 Ah 1. Ah 2 Bm C 1 C 2 IIC 1 IIC 2 0-15 15-28 28-38 38-64 64-76 76-94 94-120 12.2 7.5 2.3 0.4 0.2 0.6 0.3 0.20 0.17 0.15 0.04 0.05 0.07 0.04 0.47 0.49 0.39 0.09 . 0.05 0.08 0.06 SITE 2 0.44 0.44 0.44 0.24 0.36 0.31 0.31 0.50 0.50 0.70 0.26 0.17 0.26 0.24 1.85 1.60 0.28 0.45 0.65 0.48 4.11 2.46 0.58 Ah 1 R 0-20 16.6 0.20 1.33 0.50 1.44 6.45 1.28 5.03 SITE 3 Ah 1 Ah 2 Bm Bh R 0-10 10-15 15-30 30*36 11.7 11.4 3.4 7.0 0.23 0.27 0.10 0.19 1.28 1.42 0.66 1.19 0.45 0.42 0.24 0.33 1.40 1.56 1.04 1.36 2.85 2.05 0.45 1.02 1.28 0.65 2.87 1.71 0.69 SITE 4 Ah 1 Ah 2 Bm BC C R 0-10 10-20 20-33 33-60 60-105 17.4 11.1 4.9 2.1 0.7 0.27 • 0.22 0.14 0.09 0.03 1.14 1.13 0.78 0.49 0.25 0.48 0.46 0.31 0.25 0.18 0.92 1.96 1.64 1.04 0.57 5.65 2.05 0.53 1.51 1.33 0.98 3.74 1.54 0.54 ro to TABLE 2 (continued) Horizon Depth O.M Na Pyrophosphate NH. Oxalate Ch Cf Ch/Cf cm % Fe % Al % Fe % Al % % % SITE 5 Ah 1 0-18 14.1 0.24 0.46 0.46 0.58 2.40 1.12 2.14 Ah 2 18-36 6.6 0.20 0.55 0.48 0.52 1.45 0.64 2.27 Bm 36-50 0.9 0.09 0.13 0.33 0.18 0.10 0.16 0.63 IIC 1 50-100 0.8 0.08 0.09 0.41 0.31 IIC 2 100 + 0.5 0.06 0.09 0.28 0.24 SITE 6 Ah 1 0-10 16.4 0.18 0.49 0.43 0.84 3.15 1.20 2.63 Ah 2 10-23 12.0 0.18 0.52 0.42 0.76 1.50 0.73 2.05 Ah 3 23-33 6.3 0.21 0.83 0.44 1.24 1.25 1.03 1.21 Bm 33-58 4.2 0.13 0.64 0.37 1.44 0.28 0.47 0.60 BC 58-91 1.3 0.06 0.29 0.28 0.61 C 91 + 0.4 0.02 0.08 0.18 0.24 SITE 7 Ah 1 0-10 13.9 0.27 0.65 0.54 0.79 T.55 1.09 1.42 Bf 10-38 3.2 0.07 0.36 0.53 1.20 0.35 0.55 0.64 Bm R 38-66 3.0 0.13 0.46 0.47 1.04 0.40 0.56 0.71 31 degree to the high content of organic matter with i t s many organic functional groups as well as due to some hydroxy aluminum. Due to the climate and vegetation, the s o i l s are not leached extensively. Oak forests are known to draw much larger quantities of ash elements, including bases, into the bi o l o g i c a l cycle than do coniferous forests and this tends to prevent rapid leaching [Rozhnova and Kasatkina, 1970; Yakushevskaya, 1964]. The s o i l s are c l a s s i f i e d into both the Canadian and the American. System of Soi l C l a s s i f i c a t i o n at the Great Group l e v e l s . The surface horizons are c l a s s i f i e d as sombric i n the Canadian system [C.S.S.C., 1970] and umbric epipedons i n the American system [S.S.S., 1960, 1967] on the basis of the high organic matter content and low base saturation (< 50%). The c r i t e r i a used to c l a s s i f y these s o i l s depended mostly on the morphology of these s o i l s since the s o i l s were s t r a t i f i e d due to the nature of deposition making i t d i f f i c u l t to compare the B and C horizon on chemical c r i t e r i a as required for Podzols. Horizons such as an Ah high in extractable iron and aluminum (Ah f ) , Bfh or Bm are a l l very s i m i l a r in nature except for the dominant expressing c r i t e r i a such as the humic, podzolic or modified nature of the horizon on the basis of the morphology expressed pites 1 to 6 are c l a s s i f i e d as Sombric Brunisols according to the Canadian So i l C l a s s i f i c a t i o n System (C.S.S.C., 1970) or Umbric Inceptisols according to the American System [S.S.S., 1960, 1967] while s i t e 7 has the morphology of a Sombric Podzols according to Canadian system or a Spodosol according to the American system because of the high chroma and the presence of amorphous coatings and free sesquioxides. S o i l development has occurred to a greater extent at s i t e 7 than i n any of the other s i t e s . That can be seen by the development TABLE 3 C l a s s i f i c a t i o n of the Soils into the Canadian and American Systems of S o i l C l a s s i f i c a t i o n Site Canadian C l a s s i f i c a t i o n (CSSC, 1970) American C l a s s i f i c a t i o n (Soil Survey Staff, 1960, 1967) 1 Orthic Sombric Brum'sol Umbric Distrochrept 2 L i t h i c Sombric Brum"sol Umbric L i t h i c Distrochrept 3 Orthic Sombric Brunisol Umbric Distrochrept 4 L i t h i c Sombric Brunisol Umbric L i t h i c Distrochrept 5 Orthic Sombric Brunisol Umbric Distrochrept 6 Orthic Sombric Brunisol Umbric Distrochrept 7 Sombric Ferro-Humic Podzol Umbric Humic Haplorthod 33 of a Podzol B horizon (spodic). This i s p a r t i a l l y the r e s u l t of the micro-climatic differences between the sit e s with i t s associated vegetation. The other s i t e s are less developed due to a more intensive base cycling associated with grass and Garry oak than the coniferous vegetation of s i t e 7 [Rozhnova and Kasathina, 1970; Yakushevskaya, 1964]. The c l i m a t i c factor i s very important i n the formation of these s o i l s since i t controls the vegetation which i n turn has an e f f e c t upon the development of the s o i l . Organic matter in the s o i l may profoundly a f f e c t i t s development, but this influence must be d i f f e r e n t i a t e d from that of vegetation as a soil-forming factor [Cruickshank, 1972]. The climate of t h i s area has been e s s e n t i a l l y the same since g l a c i a t i o n as shown by pollen analysis of bogs at Langford Lake, V i c t o r i a . No d r a s t i c differences were observed that could not be accounted for by normal succession [Hansen, 1953]. Garry oak and arbutus which r e f l e c t the comparatively dry climate were present at a nearly constant amount throughout the bogs formation indicating that s i m i l a r processes i n s o i l formation have been i n operation since r e l a t i v e l y soon after g l a c i a t i o n . The build-up of the high amounts of organic matter in the surface horizon of these s o i l s i s due mainly to the climate and vegetation. The'vegetation of grass and Garry oak results i n a large l i t t e r f a l l annually. This l i t t e r has a r e l a t i v e l y low C/N r a t i o that i s favourable for rapid decomposition i f conditions are suitable. The climate with i t s large summer water d e f i c i t and cool winter temperatures results i n a prolonged period annually during which decomposition i s very slow. Only during the spring and f a l l are moisture and temperature conditions favourable f o r b i o l o g i c a l a c t i v i t y to decompose the organic matter. The summer drought i s thought to be responsible also for the organic matter to become clos e l y associated to the inorganic f r a c t i o n through annual desiccation. The desiccation results i n the organic matter drying upon 34 the mineral surface and thus becoming even more resi s t a n t to the bio l o g i c a l a c t i v i t y of the decomposers. The summer drought i s most severe i n the grass and grass-Garry oak s i t e s . The establishment of Garry oak and Douglas f i r forests results i n the amelioration of the climatic extremes upon the s o i l ' s surface and thus allows the processes of s o i l formation, to continue for longer periods of time. The d i f f e r e n t type of organic matter corresponding to the di f f e r e n t s i t e s i s an important factor i n the kind of s o i l formation at each s i t e . The r a t i o of humic acid to f u l v i c acid has been used as an indication of the degree of mineral destruction [Sukachev and Dy l i s , 1968].This r a t i o decreases from grass to Garry oak to Douglas f i r (Table 2). This, therefore, can be used as an indication of weathering occurring in certain s o i l s since f u l v i c acid i s more mobile and destructive than humic acids and thus accounting for podzolization i n s i t e 7. The successional pattern observed here, as i n Oregon, i s possibly the re s u l t of the amelioration effects of the vegetation upon the climate. Each succession changes the microclimate enough to make i t favourable for other species to establish and develop. This succession i s possible as long as i t i s not affected by other agents which oppose i t , such as f i r e or pestilence. The changes i n the succession r e s u l t in changes in the s o i l morphology due to di f f e r e n t processes of s o i l formation associated with each vegetational succession. CONCLUSIONS The s o i l s studied i n th i s paper show that there i s a r e l a t i o n -ship between the s o i l morphology and the vegetation. There i s a change 35 i n the organic matter with each successional change causing the factors of s o i l formation to change. The biosequence of grass and Garry oak, to Garry oak, to Douglas f i r showed an increase in s o i l formation. The grass and Garry oak, and the Garry oak forested s o i l s were associated with Sombric Brunisols. The Douglas f i r forested s o i l was associated with a Sombric Podzol. The biosequence grass and Garry oak, to Garry oak forested, to Douglas f i r forested showed that there was increased weathering with each successive vegetational change. 36 LITERATURE CITED 1. ATMOSPHERIC ENVIRONMENTAL SERVICE. 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J. of S o i l Science, Vol. 48, pp. 27-36. 18. NEWCOMBE, C.F., 1914. Pleistocene Raised Beaches at V i c t o r i a , B.C. The Ottawa Na t u r a l i s t , pp. 107-110. 19. OWEN, H.E., 1953. Certain Factors Affecting the Establishment of the Douglas-Fir {Psuedosuga taxifolia) Seedlings, M. Sc. Thesis, Oreg. State Univ., C o r v a l l i s . 20. ROEMER, H.L., 1972. The Natural Forest Succession of the Saanichton Peninsula, Vancouver Island, B.C., Ph.D. Thesis, University of V i c t o r i a . 21. ROWE, J.S., 1959. Forest Regions of Canada, Dept. of Northern A f f a i r s and National Resources, Forestry Branch, Ottawa, Bui. 123. 22. ROZHNOVA, T.A. and T.V. KASATKINA, 1970. Soi l s Forming Under Oak Forests i n the Northwest. Soviet S o i l Science 1970, No. 9, pp. 10-19. 23. RYDER, J.M. 1972. Pleistocene Chronology and Glacial Geomor-phology: Studies in Southwestern B.C. from Mountain Geomorphology, ed. 0. Slaymaker and H.J. McPherson, Tantalus Research Ltd., Vancouver. 24. SIMONSON, R.E. and S. RIEGER, 1967. S o i l s of the Andept Sub-order i n Alaska. So i l S c i . Amer. P r o c , Vol. 31, pp/ 692-699. 25. SOIL SURVEY STAFF, 1951. So i l Survey Manual, U.S.D.A. Agr. Hand-book, No. 18. 26. SOIL SURVEY STAFF, 1960, 1967. S o i l C l a s s i f i c a t i o n . Seventh Approximation, U.S.D.A., SCS, U.S. Government Printing O f f i c e , Washington, D.C. 27. SPRAGUE, F.L. and H.P. HANSEN., 1946. Forest Succession i n the McDonald Forest, Williamette Valley, Oregon. Northwest Science, Vol. XX, No. 4, pp. 89-98. 28. SUKACHEV, V. and N. DYLIS., 1968. Fundamentals of Forest Bio-geocenology, (trans, by J.M. MacLennan), Oliver and Boyd, London. 37a 29. THILENIUS, J.F., 1964. Synecology of the White-Oak Woodlands of the Willamette Valley, Oregon. Ph.D. Thesis, Oregon State University. 30. THILENIUS, J.F., 1968. The Quercus Gavryana Forest of the Williamette Valley, Oregon, Ecology 49, pp. 1124-1133. 31. UGOLINI, F.C. and A.K. SCHLICHTE, 1973. The Effect of the Holocene Environmental Changes on Selected Western Washington S o i l s , S o i l Science, Vol. 116, pp. 218-227. 32. YAKUSHEVSKAY, I.V., 1964. Novgorod "Oak Forest S o i l s , " Soviet S o i l Science, 1964, No. 12, pp. 893-901. 38 I I . PHYSICAL, CHEMICAL, MINERALOGICAL PROPERTIES AND GENESIS ABSTRACT The results of selected physical, chemical and mineralogical analysis of seven Sombric s o i l s of south-eastern Vancouver Island are presented and discussed i n r e l a t i o n to t h e i r genesis. These s o i l s are thought to be part of a biosequence of grass and Garry oak, Garry oak, and Douglas f i r successions. These s o i l s have developed.on r e l -a t i v e l y coarse parent materials that are gravelly and have sandy loam and loamy sand textures. Most of the s i l t and clay has accumulated in the surface horizon. The high amounts of organic matter associated with these s o i l s have an important a f f e c t upon the properties of these s o i l s . The d i f f e r e n t kinds of organic matter associated with each vegetational succession cause differences i n the s o i l development. I t was found that the Sombric Brunisols develop under the grass and Garry oak vegetation while Sombric Podzols develop under Douglas f i r vegetation i n this area. 39 INTRODUCTION This paper presents some of the physical, chemical and mineralogical properties of the s o i l s described previously [Broersma, 1973a]. This i s necessary i n order to allow a more precise characterization of these s o i l s . In modern s o i l c l a s s i f i c a t i o n a great deal of reliance i s placed on the quantitative composition of s o i l s [Buol et a]_. 1972]. The morphology of s o i l s should correlate closely with the overall physical, chemical and mineralogical properties and this should enable one to obtain a better understanding of the genesis of these s o i l s . MATERIALS AND METHODS Sample Preparation Samples were obtained from the s i t e s described in the paper re l a t i n g to the morphology, environment and genesis of these s o i l s [Broersma, 1973a]. Each horizon described was c a r e f u l l y sampled. S o i l samples were dried at room temperature and crushed l i g h t l y with a wooden r o l l i n g pin to pass a 2 mm sieve. Coarse fragments were weighed and discarded. A small amount of sample was ground to pass 60, mesh and 100 mesh sieves for the requirements of certain analyses. The remaining sample was stored i n cardboard food containers. Physical Analysis P a r t i c l e size d i s t r i b u t i o n was determined by the hydrometer method [Day, 1950]. The organic matter was destroyed by H 20 2(30%) and iron was not removed. Hydroscopic water was determined as outlined by Gardner [1965]. Chemical Analysis S o i l pH was determined according to two methods. On a 1:2 s o i l to 0.01 M CaCl 2 suspension and on a 1:1, s o i l to water suspension using a glass electrode and pH meter. The exchangeable a c i d i t y was determined according to the method described by Peech.[1965]. Total carbon was determined using a Leco Gasometric Carbon Analyzer [LECO, 1959]. Cation exchange capacity and exchangeable cations were determined according to the procedure outlined by Chapman [1965] using IN NH^OAc pH 7. The NH^ absorbed by the s o i l , which i s the measure of cation exchange capacity, was determined by semi-microKjeldahl pro-cedures. The exchangeable cations were determined by atomic absorption spectrophotometry. The pH dependent cation exchange capacity was determined according to the method of Clark [1965]. Total nitrogen was determined by semi-microKjeldahl methods as outlined by Bremner [1965]. Total s u l f u r was determined by a Leco Combustion Sulfur Analysis Apparatus [LECO, 1959]. Available phosphorus was determined using 0.03 N NH^F i n 0.025N HC1 as an extract and determined col o u r i m e t r i c a l l y using molyldate and stannous chloride [Jackson, 1958]. Iron and aluminum were determined according to three methods. Acid ammonium oxalate extractable Fe and Al was determined on samples ground to pass a 60 mesh sieve according to the procedure of McKeague and Day [1966]. Citrate-Bicarbonate-Dithionite extractions were done for free Fe and A l . [Weaver et al_. 1968; Mehra and Jackson, I960]. Sodium pyrophosphate extractions were determined as outlined by Bascomb [1968]. Soluble, exchangeable and e a s i l y reducible manganese was determined according to the method described by Jackson [1958]. Total elemental analysis was determined by acid digestion using HC1, HF and HCIO^ following i g n i t i o n of the sample to 900°C for about two hours. Elements were determined by atomic absorption spectrophotometry. Mineralogical Analysis S o i l s were prepared for X-ray analysis according to Jackson [1956] except that iron was removed using acid ammonium oxalate (pH 3.0). Organic matter was destroyed by hydrogen peroxide ( ^ 2 ) 30%. The separation of sand was accomplished by wet sieving using a 270 mesh sieve (53 u). The clay and s i l t were separated using the Sharpies continuous flow supercentrifuge. The centrifuge was set at a flow rate of 1850 ml/min and a speed of 5000 rpm. The s i l t f r a c t i o n was retained on the l i n e r while the clay remained in suspension. The clay was flocculated using CaCl 9. The s i l t s were washed with IN KC1 four times and then made into a s l u r r y with water in preparation for X-ray d i f f r a c t i o n . The clay f r a c t i o n was saturated with K, Mg and Mg-glycerol separately as outlined by Jackson [1956]. Oriented s l i d e s were pre-pared of each saturation. The K saturated s l i d e s upon X-ray analysis were subjected to heat treatments of 300°C and 550°C to determine i f vermiculite, montmorillonite or k a o l i n i t e were present. A Norelco X-ray diffractometer was used for analysis of the s i l t s and clays. The X-ray unit was set at 40 kilowatts and 20 milliampers and employed CuK^ radiation with a nickel f i l t e r . RESULTS AND DISCUSSION Physical Analysis The p a r t i c l e size d i s t r i b u t i o n (Table 1) gave a range in texture from gravelly sand to s i l t y clay. Most of the s o i l s , expecially the A and B horizons, had textures ranging from gravelly loam to gravelly sandy loam. There i s evidence of s t r a t i f i c a t i o n especially at s i t e s 1, 5 and 6 where l i t h o l o g i c a l d i s c o n t i n u i t i e s are readily observable. The parent materials of s i t e s 1 and 5 are the same, only the depth of the strata are d i f f e r e n t at each s i t e . These s o i l s have r e l a t i v e l y high contents of sand through-out the pedon. The surface horizons have the greatest content of fines ( s i l t and c l a y ) . The amounts of clay and s i l t decreases with depth except for s i t e s 1 and 5 where the solum i s underlain by marine s i l t s and clays. 43 TABLE 1 Selected Physical Properties of the Soils Horizon Depth(cm) Sand % S i l t . % Clay 9 % Coarse'3 Fragments %• Texture Class Hygroscopic Water % SITE 1 Ah 1 Ah 2 Bm C 1 C 2 IIC 1 IIC 2 0-15 15-28 2 8 - 3 8 38-64 64-76 76-94 94-120 7 0 . 0 7 3 . 4 7 9 . 2 9 5 . 2 8 3 . 2 2 0 . 8 1 .7 17.4 1 6 . 0 1 9 . 3 4 . 3 5 . 0 4 5 . 0 5 6 . 2 11.6 1 0 . 6 1 . 5 0 . 5 1 1 . 8 3 4 . 2 4 2 . 1 SITE 2 21 39 49 37 36 43 6 g SL g SL g L S g s g L S g CL Si C 3 . 4 2 . 4 1 . 9 0 . 6 0 . 7 3 . 8 4 . 6 Ah R 0 - 2 0 4 0 . 4 4 4 . 9 14.7 35 g L 6 . 4 SITE 3 Ah 1 Ah 2 Bm . Bh R . 0-10 10-15 15-30 3 0 - 3 6 4 7 . 7 5 3 . 5 6 6 . 7 3 8 . 9 4 0 . 4 2 9 . 7 1 3 . 5 6.1 3 . 6 SITE 4 27 23 25 46 g L g S L g S L 4 . 8 4 . 9 2 . 9 3 . 7 Ah 1 Ah 2 Bm BC C R 0-10 10-20 2 0 - 3 3 3 3 - 6 0 6 0 - 1 0 5 4 5 . 8 53.1 6 2 . 0 8 3 . 9 8 5 . 3 3 6 . 4 4 0 . 6 3 5 . 7 1 4 . 8 13.7 1 7 . 8 6 . 3 2 . 3 1 . 3 1 . 0 SITE 5 33 37 41 62 70 g L g S L g S L g L S g L S 5 . 6 6 . 1 4 . 3 2 . 6 1 . 5 Ah 1 Ah 2 Bm IIC 1 IIC 2 0 - 1 8 18-36 3 6 - 5 0 50-100 100 + 6 4 . 3 70.1 6 4 . 5 7 . 3 11 .4 1 8 . 2 2 0 . 9 2 6 . 8 4 7 . 0 5 4 . 2 1 7 . 5 9 . 0 8 . 7 4 5 . 7 3 4 . 4 31 45 37 8 • 5 g SL g S L g S L Si C Si CL 6 . 0 2 . 6 1 . 3 5.1 4 . 4 a % by weight of the <2 mm fr a c t i o n b p a r t i c l e s >2 mm based on the whole s o i l , % by weight 44 TABLE 1 (continued) Horizon Depth(cm) Sand % S i l t % Clay a % Coarse^ Fragments Texture Class Hygroscopic Water V 10 S ITE 6 Ah 1 0-10 6 2 . 8 2 3 . 5 13.7 7 S L 5 . 5 Ah 2 10-23 71 .6 2 0 . 3 8.1 15 S L 3 . 4 Ah 3 2 3 - 3 3 7 2 . 8 2 2 . 9 4 . 3 21 g L S 3 . 6 Bm 3 3 - 5 8 8 7 . 0 1 2 . 8 0 . 2 58 g s 3 . 4 B C 58-91 9 2 . 8 6 . 5 0 . 7 55 g s 0 . 6 C 91 + 9 3 . 8 6.1 0.1 47 9 S 0 . 6 SITE 7 Ah 0-10 4 7 . 8 3 9 . 0 1 3 . 2 3 L 6 . 0 Bf 10-38 5 2 . 0 3 1 . 7 1 6 . 3 37 g S L 3.1 Bm R 3 8 - 6 6 6 8 . 3 2 8 . 2 3 . 5 46 g S L 3.1 a b % by weight of the <2 mm fra c t i o n p a r t i c l e s >2 mm based on the whole s o i l , % by weight The amount of coarse fragments increase, based on the whole s o i l , with depth. The coarse fragments amount to a considerable portion of the t o t a l s o i l . The amount of coarse fragments range from about 20 percent to over 50 percent for the d i f f e r e n t s i t e s except for the marine deposits at s i t e 1 and 5. The d i s t r i b u t i o n of clay indicates that there has been l i t t l e clay translocation. A l l the s i t e s indicate a maximum amount of clay i n the surface horizons indicating that maximum weathering occurs i n the surface horizon. The hygroscopic water contents of these s o i l s seem to be highly correlated with the amount of organic matter present (Table 3) as well as clay content. Amorphous materials could also account f o r some of the hygroscopic water. Chemical Analysis The results of the chemical analysis are given i n Tables 2 to 6. Table 2 gives the results for pH, exchange a c i d i t y , exchange-able cations, cation exchange capacity and base saturation. The pH of these s o i l s show that the s o i l s are medium to strongly acid. The values are i n general lower at the surface and increase with depth, although differences between the surface and lower horizons are not s t r i k i n g . The pH values using 0.01M CaCl 2 are about 0.3-1.0 units lower than i n water. Site 1 and 5 are nearly neutral probably the r e s u l t of the influence of the marine materials. TABLE 2 Reaction and Exchange Properties of the Soils PH Exchange Acidity Exchangeable Cations CEC B.S. Horizon H20 (1:1) 0.01M CaCl 2 (1:2) Total meq/1 Al meq/1 H meq/1 Ca meq/1 Mg meq/1 K meq/1 Na meq/1 meq/100 g % SITE 1 Ah 1 Ah 2 Bm C 2 C 2 IIC 1 IIC 2 5.7 5.8 6.0 5.9 6.2 5.9 6.2 5.2 5.0 5.2 5.0 5.2 5.6 5.9' 25.0 22.0 11.5 8.0 4.0 7.5 7.5 4.2 5.2 1.9 0.9 0.1 0.1 0 20.8 16.8 9.6 7.1 3.9 7.4 7.5 12.0 8.0 3.5 1.3 3.3 13.3 17.0 2.6 1.4 0.7 0.3 0.6 4.4 7.6 0.3 0.2 0.4 0.1 0.1 0.4 0.6 0.3 1.0 0.1 0.2 0.3 0.5 0.5 34.0 23.2 12.7 4.9 6.5 25.1 29.8 44.7 45.7 37.0 38.8 66.2 74.1 86.2 SITE 2 Ah R 4.9 4.3 27.0 4.6 < 22.4 SITE 3 1.5 0.2 0.3 0.1 41.9 5.0 Ah 1 Ah 2 Bm Bh R 5.2 5.2 5.2 4.9 4.4 4.3 4.4 4.5 51.0 46.0 19.5 18.0 4.5 5.1 2.5 5.7 46.5 40.9 17.0 12.3 2.1 1.4 0.8 0.6 • 0.3 0.2 0.1 0.1 0.2 0.1 0.2 0.5 1.4 0.1 0.1 0.1 34.8 35.6 18.6 28.9 11.5 5.1 6.5 4.5 Ah 1 Ah 2 Bm B C C R 4.8 4.9 5.2 5.0 5.0 4.1 4.3 4.5 4.4 4.4 27.0 • 24.0 13.5 8.0 5.0 c 5.2 4.8 2.6 2.0 1.4 ilTE 4 21.8 19.2 10.9 6.0 3.6 2.3 1.2 0.7 0.6 0.4 0.3 0.1 0.1 0.1 0.1 0.2 0.1 0.6 0.3 0.3 0.2 0.1 0.1 0.1 0.1 47.7 37.7 24.9 19.4 13.8 6.3 6.0 5.7 6.5 TABLE 2 (continued) pH Exchange Acidity Exchangeable Cations CEC B.S. Horizon H20 (1:1) D.01 M CaCl 2 (1:2) Total meq/1 Al meq/1 H Meq/1 Ca meq/1 Mg meq/1 K meq/1 Na meq/1 meq/100 g % • SITE 5 Ah 1 Ah 2 Bm IIC 1 IIC 2 5.9 6.0 6.0 5.8 5.9 5.2 5.1 5.0 5.2 5.7 24.0 20.0 6.0 13.0 6.0 3.2 5.6 0.3 0.1 0 20.8 14.4 5.7 12.9 6.0 16.5 8.0 5.3 14.5 15.0 3.6 1.6 1.6 7.8 8.9 0.3 0.2 0.1 0.4 0.4 0.5 0.2 0.2 0.5 0.5 44.3 25.5 19.1 43.3 29.4 47.2 39.2 37.7 53.6 84.4 SITE 6 Ah 1 Ah 2 Ah 3 Bm B C C 5.3 5.3 5.3 5.6 5.6 5.5 4.7 4.7 4.9 4.8 4.8 4.7 20.0 16.0 12.0 9.5 3.5 2.0 3.2 4.3 4.4 2.0 1.5 0.8 16.8 11.7 7.6 7.5 2.0 1.2 SITE 7 15.5 10.0 6.5 2.8 1.2 0.7 3.3 1.9 0.9 0.4 0.2 0.2 0.6 0.3 0.2 0.3 0.9 0.5 0.3 0.5 0.2 0.1 0.1 0.1 48.8 33.1 25.3 19.8 10.3 5.2 40.4 38.7 30.8 18.2 23.3 28.8 Ah 1 Bf Bm R 5.3 6.0 5.9 5.0 5.4 5.3 18.0 7.0 10.0 3.0 1.3 2.2 15.0 5.7 7.8 13.0 5.5 4.3 2.8 1.1 0.6 0.6 0.6 0.6 0.3 0.2 0.2 47.2 21.2 21.2 35.4 34.9 26.9 48 The exchange a c i d i t y or exchangeable hydrogen for these s o i l s shows that there i s a decrease i n t o t a l exchange a c i d i t y with increasing depth. The surface or Ah horizons are considerably higher i n total exchange a c i d i t y than the B and C horizons. The higher values obtained for the surface horizons can be accounted f o r by the high amounts of organic matter presenf i n these horizons. The organic matter i s a source of hydrogen which i s associated with organic oxygen. The hydrogen i s probably in the nature of hydroxyls which are released i n the presence of a proton acceptor. The aluminum i n acid s o i l s constitutes a large part of the to t a l exchange a c i d i t y through hydrolysis [Jackson, 1958]. The aluminum content of the exchange a c i d i t y on the surface horizons amounts to only a small part, while in the lower horizons t h i s amounts to a con-siderable portion. These s o i l s are not extremely a c i d i c therefore account-ing f o r the low amounts of active or exchangeable aluminum. The exchangeable cations in order of dominance are Ca, Mg, K and Na. The cations a l l decrease with depth except for at the l i t h o l o g i c discontin-u i t i e s of s i t e s 1 and 5 where the to t a l exchangeable cations increase considerably. The content of exchangeable cations are very much lower f o r the grass s i t e s 2, 3, and 4. Grass s i t e 1 i s much higher than the others due to the probable influence of marine materials i n the C horizon and di f f e r e n t vegetation which consisted mostly of dry land sedges [Carix spp.) and narrow leaf plantain [Plantago maritima). The exchangeable cations f o r the Garry oak s i t e s are some-what higher than for the Douglas f i r s i t e . This i s probably the r e s u l t of higher base cycling at the Garry oak s i t e as well as more intensive 49 leaching at the Douglas f i r site [Yakushevskay, 1964; Rozhnova and Kasatkina, 1970]. The total cation exchange capacity decreases with depth at all sites. This is probably the result of the decrease in organic matter with depth (Table 3). The increase for the Bh horizon at site 3 is probably the result of the bedrock contact forming an impermeable layer causing the accumulation of organic matter and clay. The high clay and s i l t content of the marine parent material of site 1 and 5 also causes a considerable increase in the cation exchange capacity. The percent base saturation for these soils are all less than 50 percent for the A and B horizons. Sites 2, 3 and 4 have base saturation values that are very low, less than 12 percent. At site 3 the Bh horizon has an increase in the base saturation probably due to downward leaching of bases. The other remaining sites have values that are considerably higher. The values for these sites decrease to a low in the B horizon and then increase again in the C horizon. The base saturation of the Garry oak sites compared to the Douglas f i r site is somewhat higher due to a more intense base cycling. The Douglas f i r site has a lower base cycling and an increased amount of leaching. The values for organic carbon, organic matter, nitrogen, sulfur, phosphorus and the relationship between carbon and nitrogen, and carbon, nitrogen and sulfur are given in Table 3. The total carbon (C x 1.724 = organic matter) decreases with depth at all sites. The amounts of organic matter in the surface TABLE 3 Selected Chemical Properties of the Soi l Horizon Total Carbon % O.M. (%Cxl.724) % Nitrogen Sulfur C/N C/N/S • ppm-H20 Soluble Manganese NH40Ac IN pH7 ppm-IN NHd0Ac(a)j hydro-quinone Ah 1 Ah 2 Bm C 1 C 2 IIC 1 IIC 2 Ah R Ah 1 Ah 2 Bm Bh R Ah 1 Ah 2 Bm B C C R 7.06 4.36 1.34 0.25 0.11 0.33 0.19 9.61 6.83 6.59 1.94 4.07 10.08 6.45 2.82 1.23 0.42 12.17 7.52 2.31 0.43 0.20 0.57 0.33 16.58 11.70 11.36 3.35 7.02 17.39 11.13 4.86 2.12 0.72 0.57 0.37 0.17 0.06 0.01 0.03 0.02 0.76 0.55 0.43 0.15 0.32 0.89 0.51 0.23 0.12 0.03 SITE 1 0.070 0.059 0.033 0.003 0.001 0.001 0.003 0.063 0.049 0.049 0.023 0.046 0.072 0.068 0.032 0.017 0.008 12.4 11.8 7.9 4.2 11.0 11.0 9.5 SITE 2 12.6 SITE 3 12. 15. 12. 12. SITE 4 11.3 12.6 12.3 10.3 14.0 101:8:1 74:6:1 41:5:1 84:20:1 110:10:1 330:30:1 63:7:1 152:12:1 139:11:1 134:9:1 84:7:1 88:7:1 140:12:1 95:8:1 88:7:1 73:7:1 53:4:1 14 17 45 28 6 3 2 89 62 58 67 74 54 94 41 24 30 0.2 0.5 0.2 0.2 0.05 0.8 0.3 0.1 1.5 0.2 3.0 0.7 0.6 5.0 7.3 19.1 6.7 6.2 2.8 0.1 10.6 3.6 0.5 2.9 4.0 TABLE 3 (continued) Manganese Horizon Total Carbon % O.M. (%Cxl.724) % Nitrogen % Sulfur % C/N C/N/S nnm P H20 Soluble NH40Ac IN pH7 nnm IN NH40Ac(a) + hydro-quinone 1- r 1 1 1 I T " 1 SITE J Ah 1 Ah 2 Bm IIC 1 IIC 2 8.15 3.85 0.51 0.46 0.29 14.05 6.64 0.89 0.79 0.50 0.56 0.20 0.05 0.04 0.02 0.086 0.057 0.021 0.016 0.011 14.6 19.3 10.2 11.5 14.5 95:7:1 68:4:1 24:2:1 29:3:1 26:2:1 15 15 3 0 3 -1.1 0.1 0.2 0.3 6.4 1.1 1.1 9.3 14.8 SITE 6 Ah 1 Ah 2 Ah 3 Bm B C C 9.52 6.97 3.63 2.45 0.75 0.22 16.42 12.02 6.26 4.22 1.29 0.38 0.69 0.40 0.28 0.19 0.08 0.02 0.073 0.043 0.040 0.027 0.006 0.003 SITE 7 13.8 17.4 13.0 12.9 9.4 11.0 r 130:9:1 162:9:1 91:7:1 91:7:1 125:13:1 73:7:1 39 30 50 35 28 27 0.1 0.1 4.7 2.5 0.3 0.1 0.1 22.6 14.7 5.0 4.0 6.1 7.8 Ah Bf Bm R 8.05 1.83 1.72 13.87 3.16 2.97 0.40 0.12 0.12 0.051 0.014 0.023 20.1 15.3 14.3 158:8:1 131:9:1 75:5:1 40 33 49 0.2 5.9 0.3 0.2 46.5 7.6 3.6 ^ e a s i l y reducible manganese horizons are considerably higher than the B horizons. Quantities of organic matter such as found i n the surface horizons of these s o i l s are commonly associated with melanic, sombric or chernozemic s o i l s . These surface horizons are sombric because of the low base saturation (<50%) [C.S.S.C., 1968]. In the American s o i l c l a s s i f i c a -tion system these surface horizons would be umbric epipedons for the same reasons [S.S.S., 1967, 1968]. The organic matter accumulation results from quite high inputs of l i t t e r that i s not decomposed readily due to unfavourable microbial conditions in the grass and Garry oak s i t e s and fungi in the Douglas f i r s i t e [Broerma, 1973a]. The summer has severe drought conditions during the summer, while winters are cool leaving only limited time for decomposition by microbes. The t o t a l nitrogen content i s the greatest in the surface horizons at a l l s i t e s and decreases with depth. The t o t a l nitrogen values show the same general trend that i s observed for organic matter. This indicates that most of the nitrogen i s in organic combination. The tot a l s u l f u r content i s also the greatest at the surface and decreases with depth. Sulfur i s probably also closely associated with organic matter. The C/N r a t i o i n general decreases with depth indicating greater humification with increasing depth. A trend can be observed for the C/N r a t i o s of the three d i s t i n c t l y d i f f e r e n t s i t e s . The grass s i t e s have the lowest C/N r a t i o with an average of about 12.6, the Garry oak s i t e s have an average C/N r a t i o of 15.6, while the Douglas f i r s i t e has an C/N r a t i o of 20.1. The difference i n the C/N ratios for the d i f f e r e n t s i t e s indicates that the organic matter, the rate of decomposition and the degree of decomposition i s di f f e r e n t for each s i t e . The i n i t i a l C/N r a t i o according to Cruickshank [1971] for grass i s <20, for oak 30-50, while for Douglas f i r >50. The C/N/S r a t i o also decreases with depth. Only at l i t h o -l o g i c d i s c o n t i n u i t i e s does the r a t i o not follow the normal trend. The high C/S ratios (>50:1) r e s u l t in immobilization and unfavourable conditions for organic matter decomposition [Barrow, 1958]. The available phosphorus of these s o i l s show no d e f i n i t e relationship with depth or between the di f f e r e n t s i t e s . Site 1 and 5 which are developed from the same parent material have the lowest amount of available phosphorus. Site 2 consisting of a shallow Ah horizon over bedrock had the highest content of available phosphorus. The a v a i l a b i l i t y of phosphorus in acid s o i l s i s hindered by f i x a t i o n by Fe, A l , Mn, other hydrous oxides and s i l i c a t e clays [Buckman and Brady, 1969]. The available phosphorus in these s o i l s i s probably largely from organic origins. The manganese status of these s o i l s showed some interesting trends. Three dif f e r e n t types of manganese were determined, water soluble, exchangeable and e a s i l y reducible [Jackson, 1958]. Water soluble manganese was v i r t u a l l y non existent in most horizons except for a trace i n the C material of s i t e s 1 and 6 and the surface horizon of s i t e 7. The exchangeable manganese values were also very low, i n general, with numberous B and C horizons having non-detectable amounts. The surface horizons contained the greatest amount of exchangeable manganese. The e a s i l y reducible manganese 54 accounted for the greatest amount of manganese. The amounts were the greatest in the surface horizons. The Douglas f i r s i t e had the largest amount of e a s i l y reducible manganese in i t s surface horizon. The pH dependent cation exchange capacity using 0.01 M CaCl 2 was much lower (Table 4) than values obtained by IN NH^OAc pH7.0. The NH^OAc was buffered while the CaCl 2 solution was unbuffered and took on the pH of the s o i l which ranged from 4.1 to 4.9 after e q u i l i b r a -t i o n . The cation exchange capacity of the marine clay and s i l t s of s i t e 1 and 5 were about the same for both methods. The pH dependent cation exchange capacity decreased with depth. That trend i s closely related to the amount of organic matter. The difference in cation exchange capacities i s due mainly to organic matter and other amorphous materials. The exchange s i t e s of the organic matter, which are mostly functional groups such as carboxyls (R-C00H), phenolic (Ar-OH and enolic (C = C-OH), are blocked by the abundance of H ions at low pH. The organic matter cation exchange values according to Pratt and Bair [1962] changed from pH 3 to 8 by about 370 me/100 g for organic matter and 15.8 me/100 g for clay. A s i m i l a r investigation by Helling et al_. [1964] showed that cation exchange capacities varied from pH 3.5 to 8.0 by about 140 me/100 g for organic matter and 18 me/100 g for clay. The base saturation for s i t e 1, 5, 6 and 7 was about a 100% while for s i t e s 2, 3 and 4 the values were much lower and ranged from 63.5 to 87.3%. The exchangeable aluminum at these 3 s i t e s are much higher than the other 4 s i t e s . The extractable aluminum (Table 5) 55 TABLE 4 pH Dependent Cation Exchange Capacity -Horizon pH 0.01 MCaCl 2 Ca Mg Al C.E.C. (Ca+Mg+Al) %B. S. Al +Mqxl00 . Ca+Mg+Al meq/100 q SITE 1 1 Ah 1 . Ah 2 Bm C 1 C 2 IIC 1 IIC 2 4.56 4.57 4.63' 4.70 4.69 4.72 4.89 11.79 9.29 4.91 2.10 3.98 20.85 24.60 0.64 0.44 0 16 0.06 0.14 2.87 4.46 SITE 2 0.03 0.03 0.00 0.00 0.06 0.03 0.06 12.46 9.76 5.07 2.16 4.18 23.75 29.12 . 99.8 99.7 100.0 100.0 98.6 99.9 99.8 Ah R 4.17 2.41 0.04 SITE 3 1.39 3.84 . 63.8 Ah Ah Bm Bh 4.24 4.23 4.29 4.22 3.66 1.79 0.85 1.16 0.12 0.03 0.02 0.02 SITE 4 0.97 0.95 0.50 0.83 4.75 2.77 1.37 2.01 79.6 65.7 63.5 58.7 Ah 1 Ah 2 Bm BC C 4.12 4.22 4.32 4.35 4.31 3.98 1.48 2.10 0.85 0.85 0.08 0.03 0.03 0.03 0.03 SITE 5 1.58 0.83 0.31 0.36 0.44 5.64 2.34 2.44 1.24 1.32 72.0 64.5 87.3 71.0 66.7 Ah 1 Ah 2 Bm IIC 1 IIC 2 4.80 4.62 4.76 4.67 4.74 22.41 11.16 8.35 21.48 23.04 0.59 0.64 4.62 5.39 2.09 0.14 0.06 0.03 0.06 0.03 23.14 11.86 13.00 26.93 25.16 99.4 99.5 99.8 99.8 99.9 TABLE 4 (continued) Horizon PH 0.01 MCaCl, Ah 1 Ah 2 Ah 3 Bm BC C Ah Bf Bm R Ca Mg Al C.E.C. (Ca+Mg+Al) meq/100 g SITE 6 4.63 18.66 1.58 0.06 20.30 4.54 11.16 0.65 0.06 11.87 4.64 8.04 0.24 0.03 8.31 4.56 3.04 0.08 0.08 3.20 4.62 2.41 0.07 0.03 2.51 4.53 0.85 0.03 0.00 0.88 SITE 7 4.74 13.98 1 .01 0.08 15.07 4.86 6.48 0.21 0.00 6.69 4.68 4.91 0.11 0.03 5.05 %B. S. AT+MgxlOO Ca+Mg+Al 99.7 99.5 99.6 97.5 98.8 100.0 99.5 100.0 99.4 57 for s i t e s 3, 4 and 5 i s also much higher than the other s i t e s . In Table 5 the results from pyrophosphate, oxalate and di t h i o n i t e extractions for Fe and Al are presented. The pyro-phosphate extraction, which i s an indication of organically bound Fe [McKeague, 1967; Bascomb, 1968], showed a decrease i n Fe and Al with depth at a l l s i t e s . This trend i s the same as for the organic matter observed previously. The oxalate extraction which extracts t o t a l amorphous Fe [McKeague, 1967] showed a s l i g h t decrease with depth. The Al extracted by t h i s method showed a maximum in the Ah2, Bm or Bf horizon. The d i t h i o n i t e extractable Al and Fe showed a decrease with depth except for s i t e 1 and 5 at the l i t h o l o g i c discontinuity and in s i t e 3 at the rock contact. The marine materials of s i t e 1 and 5 are much higher i n Al and Fe accounting for the greater extraction. The increase in extractable Fe and Al at s i t e 3 at the bedrock contact horizon (Bh) i s due to accumulation of mobile weathering products being precipitated. ... According to McKeague et al_. [1971] an approximate difference can be made for organic complexed Fe, amorphous inorganic Fe, and the c r y s t a l l i n e Fe oxides by selective extraction of s o i l s by pyrophosphate, oxalate and d i t h i o n i t e . In Table 5 the results of these selective extractions are given. The inorganic amorphous Fe, which i s a difference between the oxalate and pyrophosphate extractable, contents decrease with depth except f o r s i t e 7 where i t increases in the Bf horizon. The extractable c r y s t a l l i n e Fe, which i s obtained by the difference of d i t h i o n i t e and oxalate extractable, indicates a s i m i l a r trend but not as pronounced. The extractable inorganic Fe which TABLE 5 Extractable Iron and Aluminum and Calculated Values for Free Iron Oxides Horizon Na-Pyropho-sphate NH4 Oxa' f ate Cit-Bicarb-Dithionite Amorphous9 Inorganic Fe Extractable^ Crystal 1 ine Fe Extractable 0 Inorganic Fe Al Fe Al Fe Al Fe Ah 1 Ah 2 Bm C 1 C 2 IIC 1 IIC 2 Ah R Ah 1 Ah 2 Bm Bh R 0.47 0.49 0.39 0.09 0.05 0.08 0.06 1.33 1.28 1.42 0.66 1.19 0.20 0.17 0.15 0.04 0.05 0.07 0.04 0.20 0.23 0.27 0.10 0.19 0.50 0.50 0.70 0.26 0.17 0.26 0.24 1.44 1.40 1.56 1.04 1.36 0.44 0.44 0.44 0.24 0.36 0.31 0.31 0.50 0.45 0.42 0.24 0.33 0.53 0.53 0.45 0.13 0.10 0.25 0.15 1.28 1.35 1.35 0.75 1.13 SITE 0.73 0.70 0.72 0.37 0.58 1.33 1.05 SITE 1.12 SITE 1.23 1.23 0.71 0.77 1 0.24 0.27 0.29 0.20 0.31 0.24 0.27 2 0.30 3 0.22 0.22 0.14 0.14 0.29 0.26 0.26 0.13 0.22 1.02 0.74 0.62 0.78 0.78 0.47 0.44 0.53 0.53 0.55 0.33 0.53 1.26 1.01 0.92 1.00 1.00 0.61 0.58 aAmorphous inorganic Fe = oxalate Fe - pyrophosphate Fe bExtractable c r y s t a l ! i n e Fe = d i t h i o n i t e Fe - Oxalate Fe Extractable inorganic Fe = d i t h i o n i t e Fe - pyrophosphate TABLE 5 (continued) Na-Pyropho- NH4 C i t - Bicarb- Amorphous3 Extractable' 3 Extractable 0 sphate Oxalate Dithionite Inorganic Crystal!ine Inorganic Horizon Al Fe Al Fe Al Fe Fe Fe Fe SITE 4 Ah 1 1.14 0.27 0.92 0.48 1.23 1.19 0.21 0.71 0.92 Ah 2 1.13 0.22 1.96 0.46 1.35 1.02 0.24 0.56 0.80 Bm 0.78 0.14 1.64 0.31 0.93 0.69 0.17 0.38 0.55 B C 0.49 0.09 1.04 0.25 0.60 0.67 0.16 0.42 0.58 C R 0.25 0.03 0.57 0.18 0.28 0.62 0.15 0.44 0.59 SITE 5 Ah 1 0.46 0.24 0.58 0.46 0.50 0.82 0.22 0.36 0.58 Ah 2 0.55 0.20 0.52 0.48 0.55 0.81 0.28 0.33 0.61 Bm 0.13 0.09 0.18 0.33 0.13 0.67 0.24 0.34 0.58 IIC 1 0.09 0.08 0.31 0.41 0.28 1.64 0.33 1.23 1.56 IIC 2 0.09 0.06 0.24 0.28 0.13 0.99 0.22 0.71 0.93 SITE 6 Ah 1 0.49 0.18 0.84 0.43 0.60 0.80 0.25 0.37 0.62 Ah 2 0.52 0.18 0.76 0.42 0.58 0.77 0.24 0.35 0.59 Ah 3 0.83 0.21 1.24 0.44 0.93 0.92 0.23 0.48 0.71 Bm 0.64 0.13 1.44 0.37 0.78 0.79 0.24 0.42 0.66 B C 0.29 0.06 0.61 0.28 0.33 0.54 0.22 0.26 .0.48 C 0.08 0.02 0.24 0.18 0.10 0.27 0.16 0.09 0.25 TABLE 5 (continued) Horizon Na-Pyropho-,sphate NH4-Oxalate Cit-Bicarb-Dithionite Amorphous3 Inorganic Fe Extractable' 3 Crystal 1ine Fe Extractable 0 Inorganic Fe .Al Fe Al Fe Al Fe Ah Bf Bm R 0.65 0.36 0.46 0.27 0.07 0.13 0.79 1.20 1.04 0.54 0.53 0.47 0.85 0.72 0.63 SITE 1.12 1.17 0.81 7 0.27 0.46 0.34 0.58 0.64 0.34 0.85 1.10 0.68 i s obtained by the difference of d i t h i o n i t e and pyrophosphate Fe does not show a regular trend. In s i t e 7 the Bf stands out using the extractable inorganic Fe as the horizon of iron oxide accumulation. The data shows that s i t e 7 only has the d i s t r i b u t i o n of Fe typical of a Podzol. The Al extractable by oxalate also shows a maximum accumulation in the Bf horizon of s i t e 7. A l l the other si t e s show a maximum accumulation in the A horizon. This data support the morphological findings that the s o i l s are a l l Sombric Brunisols except for s i t e 7 or the Douglas f i r s i t e which i s a Sombric Podzol. The elemental analysis of the s o i l s are given in Table 6. Similar horizons within a pedon were combined on a weighted average basis. No d e f i n i t e trends are observed from the data because the materials deposited were not very homogeneous and s t r a t i f i c a t i o n can be observed at most s i t e s . The S i 0 2 to P^O^ and the A l t o TiC^ ratios have been used as indexes of weathering. The A^O^ to TiC^ r a t i o decreases as the amount of A^Og i s l o s t as a r e s u l t of weathering. The SiC^ to PwjOg r a t i o increases as the degree of weathering increases. Although i t i s d i f f i c u l t to observe trends of weathering because of s t r a t i f i c a t i o n i n general both weathering indexes go hand in hand. At the contact of d i f f e r e n t textures accumulation of weathered products are observed by increases i n the AlgQg to Tio2 ratios and decreases in the S i 0 2 to R202 ratios as in s i t e 1, 3, 5 and 6. At a l l s i t e s the greatest amount of weathering seems to have occurred in the A horizon, except TABLE 6 Elemental Analysis of the <2 mm Soil Horizon A1 20 3 F e2°3 T i 0 2 S i 0 2 Na20 01 K 20 MgO CaO - Mn02 A1 20 3 T i 0 2 S i 0 2  R2°3 Loss on Ignition % 10 /o SITE 1 Ah Bm C I IC 13.44 9.96 10.19 14.91 4.26 3.90 3.17 6.86 1.02 1.24 0.97 1.44 75.26 80.34 80.83 70.77 2.40 1.64 2.01 2.09 0.96 0.73 0.80 1.24 SITE 2 1.34 1.05 0.93 1.68 1.18 1.06 1.04 0.88 0.14 0.08 0.06 0.13 13.18 8.03 10.51 10.35 4.25 5.80 6.05 3.25 13.50 5.65 . 2.64 6.33 Ah R 14.21 5.28 1.15 74.64 1.88 1.07 SITE 3 1.06 0.50 0.21 12.36 3.83 24.16 Ah Bm Bh 11.02 10.26 11.94 3.98 3.05 3.55 0.97 0.98 0.95 80.22 82.34 79.64 1.57 1.51 1.76 0.88 0.79 0.89 SITE 4 0.80 0.65 0.73 0.42 0.36 0.46 0.14 0.06 0.08 11.36 10.47 12.57 5.35 6.19 5.14 27.78 9.65 14.29 Ah Bm C 13.59 7.24 7.13 5.15 4.71 4.48 1.05 1.03 1.02 75.34 84.94 81.74 1.90 1.03 2.47 0.94 0.52 1.31 1.15 0.53 1.05 0.69 0.25 0.69 0.19 8.05 0.11 12.94 7.03 6.99 4.02 7.10 7.04 21.23 11.42 6.74 TABLE 6 (continued) Horizon A 1 2 0 3 F e2°3 T i0 2 , S i 0 2 Na20 K20 MgO CaO Mn02 A1 2 0 3 T i0 2 S i0 2  R2°3 Loss on Ignition % to SITE 5 Ah 11.96 4.15 0.90 77.53 2.17 0.89 1.11 1.16 0.13 13.29 4.81 17.25 Bm 15.01 5.41 1.20 72.10 2.61 1.12 1.41 1.03 0.11 12.51 3.53 5.74 IIC 17.35 6.94 1.57 68.85 2.00 1.26 1.44 0.48 0.11 11.05 2.83 7.03 SITE 6 Ah 9.54 3.89 1.22 80.50 1.70 0.76 1.21 1.04 0.14 7.82 4.54 10.85 Ah 2 11.74 5.08 1.44 76.40 1.92 0.76 1.39 1.11 0.16 8.15 4.54 10.85 Bm 8.75 3.63 1.30 81.88 1.49 0.60 1.15 1.12 0.08 6.73 6.13 6.60 C 13.04 3.95 0.92 75.01 2.86 1.13 1.28 1.67 0.14 14.17 4.41 1.71 SITE 7 Ah 12.13 4.26 1.00 77.11 2.11 1.01 0.90 1.08 0.04 12.13 4.70 19.40 Bf 11.94 3.32 1.10 77.61 2.59 1.19 1.05 1.09 0.11 10.85 5.09 8.38 cn co 64 at s i t e 4 where the amount of sesquioxides decreases with depth into the C. Mineralogical Analysis 0 The results of the mineralogical analysis are presented in Table 7. The mineralogy of these s o i l s are a l l very s i m i l a r . Kaolinite and c h l o r i t e were found in each horizon. The clay f r a c t i o n was dominated by k a o l i n i t e , c h l o r i t e , quartz and feldspar (plagioclose) with vermiculite being common. I l l i t e was found i n the marine clays and s i l t s as well as at s i t e 6 and 7. Occasionally amphibole was detected. In the s i l t f r a c t i o n greater quantities of quartz, plagio-clase, feldspar were found. Kaolinite and c h l o r i t e were also present while i l l i t e , vermiculite and amphibole were detected occasionally. More primary minerals were observed to be present i n the s i l t f r a c t i o n . No movement of one mineral r e l a t i v e to another was detected. Clay translocation was not evident. The clay minerals appear to be inherited from the parent materials. The c h l o r i t e was found to be the Fe-Mg type. The Fe-Mg r i c h specimens give an intense second order peak and a weak f i r s t order peak [ C a r r o l l , 1970; Jackson, 1964]. It appears that the i l l i t e and vermiculite are being weathered to k a o l i n i t e and especially c h l o r i t e in the surface horizons since i l l i t e and vermiculite are found only at depth. The formation of TABLE 7 Mineralogy of the Clay and Silt Fractions of the Soils Clay Fraction ^ Si lt Fraction Horizon i d Qe F f A 9 Ka C b V c . jd Q e F f A 9 S] [TE 1 Ah 1 + + + + + + + Ah 2 + + + + + + + + Bm + + + + + + + + + + C 1 + + + + + + + + + C 2 + + + + + . + + + + + + + IIC 1 + + + + + + + + + + + IIC 2 + + + + + + + + + + + + Sl TE 2 Ah + + + + + + + + + + R SI TE 3 Ah 1 + + + + + + + + + + Ah 2 + + + + + + + + + Bm + + + + + + + + Bh + + + + + + + + + R cn cn TABLE 7 (continued) Clay Fraction S i l t Fraction Horizon Ah 1 Ah 2 Bm B C C R Ah 1 Ah 2 Bm IIC 1 IIC 2 Ah 1 Ah 2 Ah 3 Bm B C C + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + r + + + + + + + + + + + + + + + + + + + + + + + + + +: SITE 4 + + + + + + + + + + SITE 5 SITE 6 + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + TABLE 7 (continued) Clay Fraction S i l t Fraction Horizon V c i d Q E F f A 9 I d Q E F f Q G Ah 1 Bf Bm + + + + + + + + + + + + s n + + + "E 7 + + + + + + + + + + + + + a k a o l i n i t e equartz + present b c h l o r i t e cvermiculite d i l l i t e ^feldspar (plagioclase) 9amphibole c h l o r i t e i s due to the p r e c i p i t a t i o n of aluminum liberated from s i l i c a t e minerals between the units of expanding-layer p h y l l o s i l i c a t e s [Clark et al_. 1962; Clark and Brydon, 1963]. The drying of the s o i l , which i s c h a r a c t e r i s t i c of s o i l s in t h i s area [Broersma, 1973a], appears to be necessary for the formation of well-ordered c h l o r i t e . Genesis of the Sombric S o i l s The s o i l s studied have developed on r e l a t i v e l y young parent materials from the Pleistocene epoch.The parent materials are not homogeneous. The high amounts of sand and s i l t and low amounts of clay in these s o i l s indicate that weathering has not been severe. This i s also apparent by the high percentage of coarse materials in these s o i l s . The maximum accumulation of fines was found within the surface horizons which indicates that weathering occurs mostly within these horizons. That i s because the greatest fluctuation in climate and biolo g i c a l a c t i v i t y occurs at the surface of the s o i l s . A s a l t and pepper appearance was observed i n the Ah horizon of s i t e 5 which may be from eolian materials from the nearby beaches. This could be an important factor in causing the increase of the s i l t content of these s o i l s since most are found within reasonable distance from the beaches. Chemical weathering also plays are important role in the genesis of these s o i l s as was evidenced by the morphological expression of the p r o f i l e [Broersma, 1973a]. The high summer temperatures and the associated drought and the cool winter temperature cause only limited weathering in these s o i l s . These same conditions cause the buildup of organic matter as a resu l t of the slow rates of decomposition by biological agents associated with these condition. The organic matter has an important role in both the physical and chemical properties of these s o i l s as was shown by the analysis. Effec t i v e leaching in these Sombric s o i l s depends upon the vegetation and micro-climate of the di f f e r e n t s i t e s . The grass and grass-Garry oak si t e s do not have extensive leaching due to the rapid base cycling of t h i s kind of vegetation [Russel, 1952]. The Garry oak si t e s also have rapid base cycling [Yakushevskaya, 1964; Rozhnova and Kasatkina, 1970] which r e s u l t in limited leaching of these s o i l s . Douglas f i r sit e s are more extensively leached due to a very li m i t e d base cycle, the slow decomposition rate of the organic matter with i t s high C/N r a t i o and the production of high amounts of f u l v i c acid. The f u l v i c acid i s one of the most destruc-t i v e organic acids found in the s o i l and i s important in the move-ment of cations in s o i l s [Sukachev, 1964; Mortensen, 1963]. Where leaching i s ef f e c t i v e as in the Douglas f i r s i t e s the s o i l s became podzolic in nature and sesquioxides are mobilized a f t e r the bases become depleted. The s o i l s associated with t h i s study are thought to be part of a biosequence of grass, grass and Garry oak, Garry oak to Douglas f i r . The s o i l s develop with the vegetation changes from Sombric Brunisols to Sombric Podzols. The climate, vegetation, weathering processes and biol o g i c a l factors are recognized being s i g n i f i c a n t factors in the formation of these s o i l s . 70a CONCLUSIONS The physical and chemical properties of these s o i l s are closel y related to the organic matter d i s t r i b u t i o n in these s o i l s . The c l a s s i f i c a t i o n of these s o i l s on the basis of chemical c r i t e r i a i s d i f f i c u l t due to the lack of true 1C horizons due to the v a r i a b i l i t y of the s u r f i c i a l deposits and also due to the high amounts of Fe and Al present i n the surface horizons. Some of the high sesquioxide content of the surface horizons could be due to pre-weathering of the s u r f i c i a l deposits p r i o r to present day s o i l forming processes. The s o i l s were c l a s s i f i e d as Orthic Sombric or L i t h i c Sombric Brunisols and Humo Ferric Podzols on the basis of weathering, Ch/Cf ratios and colour. C l a s s i f i c a t i o n depended mostly on the morphology expressed by these s o i l s . Shallow Sombric horizons over bedrock (Site 2) were very d i f f i c u l t to c l a s s i f y and did not r e a l l y f i t i n any s o i l order d i s t i n c t l y . The Sombric surface horizon was the main c r i t e r i a for the c l a s s i f y i n g of these s o i l s into the Brunisolic Order. 71 LITERATURE CITED 1. ALEXANDER, M., 1967. Introduction to S o i l Microbiology, , John Wiley and Sons, Inc., New York. 2. BARROW, N.J., 1958. Effect of the Nitrogen and Sulfur Content of Organic Matter on the Production of Ammonia and Sulfate. Nature, Vol. 101, pp. 1806-1807. 3. BASCOMB, C.L., 1968. D i s t r i b u t i o n of pyrophosphate extractable iron and organic carbon i n s o i l s of various groups, J. S o i l S c i . 19, pp. 251-268. 4. BREMNER, J.M., 1965. Total Nitrogen. In C.A. Black et al_. (ed.) Methods of So i l Analysis, Part 2, Chemical and Microbiological Properties. Agronomy 9, pp. 1149-1178. 5. BROERSMA, K., 1973. Dark S o i l s of the V i c t o r i a Area, Vancouver Island, B.C. Environment, Morphology and Genesis, Master Thesis, U.B.C. 6. BUCKMAN, H.O. and N.C. BRANDY, 1969. The Nature and Properties of S o i l s , Collier-MacMillan Ltd., London. 7. CARROLL, D., 1970. Clay Minerals: A Guide to Their X-Ray I d e n t i f i c a t i o n , The Geological Society of America, Special Paper 126. 8. CHAPMAN, H.D., 1965. Cation-exchange Capacity. In C.A. Black, et aK (ed.), Methods of S o i l Analysis-. Part 2, Chemical and Microbiological Properties. Agronomy 9, pp. 891-901. 9. CLARK, J.S. and J.E. BRYD0N, 1963. Characteristics and Genesis of Concretionary Brown S o i l s of B.C., So i l Science 96, pp. 410-417. 10. CLARK, J.S., J.E. BRYD0N and L. FARSTAD, 1962. Chemical and Clay Mineralogy Properties of the Concretionary Brown So i l s of B.C., Canada, S o i l Science 95, pp. 344-352. 11. J.S. CLARK, J.A. McKEAGUE, and W . E . NICH0L, 1965. The Use of pH-Dependent Cation Exchange Capacity for Characterizing the B Horizons of Brum'solic and Podzolic S o i l s , Can. J . of So i l S c i . , Vol. 46, pp. 161-166. 12. CRUICKSHANK, 1971. S o i l Geography, David and Charles Publishers, Ltd. 13. C.S.S.C., 1968. The System of S o i l C l a s s i f i c a t i o n for Canada. Canada, Dept. of Agr., Ottawa. 72 14. DAY, R., 1950. Physical Basis of P a r t i c l e Size Analysis by the Hydrometer Method, S o i l Science, Vol. 70, pp. 363-374. 15. GARDNER, W.H., 1965. Water Content. In CA. Black et al_. (ed.), Methods of Soil Analysis. Part 1, Physical and Mineral-ogical Properties, Agronomy 9, pp. 82-127. 16. HELLING, C.S., G. CHESTERS, and R.B. COREY, 1964. Contribution of Organic Matter and Clay to S o i l Cation-Exchange Capacity as Affected by pH of the Saturating Solution, S o i l S c i . Soc. Amer. Proc. 28, pp. 517-520. 17. JACKSON, M.L., 1956. Soil Chemical Analysis, Advanced Course, Pub. by author, University of Wisconsin, Madison, 991 pp. 18. JACKSON, M.L., 1958. S o i l Chemical Analysis, Prentice H a l l , Inc., Englewood C l i f f s , N.J., 498 pp. 19. JACKSON, M.L., 1969. S o i l Clay Mineralogical Analysis (ed.), Rich, C.I. and G.W. Kunze i n S o i l Clay Mineralogy, The University of North Carolina Press, Chapel H i l l . 20. LECO, 1959. Instruction Manual for Operation of Leco Carbon and Sulfur Analyzers. Laboratory Equipment Corp., St. Joseph, Mich. 21. MEHRA, O.P. and M.L. JACKSON, 1960. Iron Oxide Removal from Soi l s and Clays by a D i t h i o n i t e - C i t r a t e System Buffered with Sodium Bicarbonate, Clay and Clay Minerals, Vol. 5, pp. 317-22. McKEAGUE, J.A., 1967. An Evaluation of 0.1 M Pyrophosphate and Pyro-phosphate^" thionite in Comparison with Oxalate as Extractants of the Accumulation Products in Podzols and Some Other S o i l s , Can. J . of S o i l S c i . , Vol. 47, pp. 95-99. 23. McKEAGUE, J.A., J.E. BRYD0N and N.M. Miles, 1971. D i f f e r e n t i a t i o n of Forms of Extractable Iron and Aluminum i n S o i l s , S o i l S c i . Soc. Amer. P r o c , Vol. 35, pp. 33-42. 24. McKEAGUE, J.A. and J.H. DAY, 1966. Dithionite and Oxalate Extractable Iron and Aluminum as Aids i n D i f f e r e n t i a t i n g Various Classes of S o i l s , Can. J. S o i l S c i . , Vol. 46, pp. 13-22. 25. M0RTENSEN, J.L., 1963. Complexing of Metals by S o i l Organic Matter, S o i l S c i . Amer. P r o c , Vol. 27, pp. 179-185. 26. PEECH, M., 1965. Exchange A c i d i t y . In CA. Black et al_. (ed.), Methods of S o i l Analysis, Part 2, Chemical and Microbiological Properties, Agronomy 9, pp. 905-912. 73 PRATT, P.F. and F.L. BAIR, 1962. Cation-Exchange Properties of Some Acid S o i l s of C a l i f o r n i a , Hilgardia 33, pp. 689-706. ROZHNOVA, T.A. and T.V. KARATKINA, 1970. So i l s Forming Under Oak Forest i n the Northv/est, Soviet S o i l Science, 1970, No. 9, pp. 10-19. RUSSEL, E.W., 1952. Soi l Conditions and Plant Growth, Longmans, Green and Co., Toronto. SOIL SURVEY STAFF, 1967, 1968. S o i l C l a s s i f i c a t i o n . 7th Approx-imation and Supplements. U.S.D.A., S.C.S., U.S. Government Pri n t i n g O f f i c e , Washington, D.C. SUKACHEV, V. and N. DYLIS, 1964. Fundamentals of Forest Bio-geocenology, Oliver and Boyd, Edinburg. WEAVER, R.M., J.K. SYERS and M.L. JACKSON, 1968. Determination of S i l i c a i n Citrate-Bicarbonate-Dithionite Extracts of S o i l , S o i l S c i . Soc. Amer. Proc. 32, pp. 497-501. YAKUSHEVSKAYA, I.V., 1964. Novgord "Oak Forest S o i l s , " Soviet S o i l Science, 1964, No. 12, pp. 893-901. 74 I I I . NATURAL ORGANO-MINERAL COMPLEXES IN SOME SOMBRIC SOILS OF THE VICTORIA AREA, VANCOUVER ISLAND ABSTRACT The natural organo-mineral complexes i n the surface horizons (Ah) of s i x d i f f e r e n t s i t e s of Sombric s o i l s of the V i c t o r i a Area, Vancouver Island were studied. Three s i t e s were associated with grass and grass and Garry oak {Quercus gavvyana), two sites with Garry oak forested, and one s i t e Douglas f i r [Psuedostuga menziesii) forested. The s o i l s were dispersed u l t r a s o n i c a l l y and then separated into fractions consisting of coarse s i l t , fine s i l t , coarse clay and fine clay. The separates were freeze dried and used to study the organo-mineral d i s t r i b u t i o n , the di s t r i b u t i o n of organic matter i n rela t i o n to the whole s o i l and surface area, the nature of the organic matter and the bridging or binding cation of the complexes. 75 INTRODUCTION The purpose of this study was to elucidate the organo-mineral complexes that occur i n the Sombric s o i l s of the V i c t o r i a Area, Vancouver Island. The morphology and chemical characterization of these s o i l s [Broersma, 1973a and b] has shown that the organic matter and inorganic matter are closely associated or complexed. The term "organo-mineral complex" denotes this i n t r i c a t e association or union of the organic and inorganic f r a c t i o n s . The importance of the union of organic matter and mineral matter in s o i l s to form organo-mineral complexes has only been realized for a r e l a t i v e l y short period. The investigations of s o i l s are usually oriented towards either the inorganic or organic f r a c t i o n . An investigator interested in the inorganic f r a c t i o n usually destroys the organic matter by oxidation and studies the inorganic fraction as a separate i d e n t i t y . The organic s o i l s c i e n t i s t extracts the organic portion for detailed studies but neglects the inorganic part. Although this s t i l l occurs the importance of organo-mineral complex has been recognized. Jacks [1963] states that the organo-mineral complex formation i s a synthesis as v i t a l to the continuance of l i f e as, and less under-stood, than photosynthesis. Scharpenseel [1967] agrees on the importance of organo-mineral complexes when he states that the formation of organo-mineral complexes in s o i l i s one of Nature's most outstanding features i n sustaining organic l i f e on earth. Now that the importance of these complexes has been realized t h e i r study i s s t i l l limited by the techniques available. Numerous studies have been carried out on a r t i f i c i a l l y pre-pared organo-clay complexes [Greenland, 1965a]. These studies were necessary to obtain information about the mechanism of interaction and the nature of the resu l t i n g complexes. Very few studies have been conducted on the study of natural organo-mineral complexes [Dudas and Pawluk, 1968; Kyama et al_., 1969; Arshad and Lowe, 1966]. Organo-mineral complexes are produced i n the s o i l s because of the pedogenic processes which occur i n s o i l and cause the organic substances to enter into a complex relationship with the inorganic f r a c t i o n . Different relationships e x i s t i n d i f f e r e n t s o i l s due to the numerous events that take place simultaneously or i n a sequence to mutually reinforce or contradict each other [Rode, 1962; Simonson, 1959]. Volobuyev [1970] states that the variety i n the composition and nature of the organo-mineral part of the s o i l i s largely a manifestation of some c h a r a c t e r i s t i c reactions among the organo-mineral compounds, the s o i l solution and the gaseous phase which are also s p e c i f i c to the corresponding s o i l groups. The purpose of th i s paper was to study Sombric s o i l s from southern Vancouver Island to determine: 1. the d i s t r i b u t i o n of the organic matter i n r e l a t i o n to the inorganic components, 2. the nature of the organic matter involved, and 3. the importance of cations involved i n the complexes. 77 MATERIALS AND METHODS Surface horizons (Ah) of a number of s o i l s described in an e a r l i e r paper [Broersma, 1973a] were chosen for this study. Site 3 and the Ah 2 horizon of s i t e 4 were eliminated from this study to decrease the number of samples since these s o i l s were si m i l a r to s i t e 1 and 2. Description of Sites Site 1 The s o i l i s a Sombric Brunisol which developed from two to three feet of marine sand and gravel on g l a c i a l marine clay and s i l t . The s o i l was vegetated with grass and some dryland sedges {Cavix spp.) and narrow leaf plantain {Plantogo mavitima). The s i t e i s surrounded by Broom {Cytisus scopavius) and scattered Garry oak [Quercus gavvyana). S i t e 2 The s o i l i s a L i t h i c Sombric Brunisol developed from a shallow sandy loom t i l l over bedrock. The s i t e i s vegetated by grasses, vetch and mosses. Site 4 This s o i l i s a well developed Sombric Brunisol. The parent material consisted of coarse textured marine materials over sandy loam g l a c i a l t i l l . The vegetation consisted mainly of grasses and Broom with Garry oak i n the immediate v i c i n i t y . Site 5 This s o i l i s a well developed Sombric Brunisol. The parent material consisted of two feet of marine sand and gravel over g l a c i a l marine clay and s i l t . The vegetation consisted mainly of Garry oak wi some small aspen (Populus tremuloides) . The understory was dense, consisting of snowberry {Symphoricarpus albus) and some grasses and wild rose [Rosa gynmocarpa). Site 6 This s o i l i s a well developed Sombric Brunisol. The parent material consisted of greater than four feet of marine sand and gravel over bedrock. The vegetation consisted of Garry oak with a dense understory of snowberry. Broom occurred around the edge of the oakstand. Site 7 This s o i l i s a Sombric Podzol developed i n shallow sandy loam t i l l over bedrock. The vegetation consisted of Douglas f i r (Psuedotsuga menziesii) and few braodleaf maple (Acer macrophyllum). The unjerstory consisted of Oregon grape (Berberis aquifolium), huckleberry (Vaccinium parvifolium), ocean spray spirea (Holodiscus discolor) and ferns. Also some Garry oak was observed on rocky or xeric s i t e s . Methods In an attempt to avoid destruction of the organic matter in i t s relationship with the inorganic matter as much as possible, u l t r a -sonic techniques were used to disperse the s o i l p r i or to p a r t i c l e size separation. Edwards and Bremner [1964] have reported that ultrasonic vibration gives good dispersion i n the absence of other dispersing agents. A Bronwill Biosonik I I I probe type unit was used to produce ultrasonic vibrations. Samples consisting of 20 grams of s o i l and 100 grams of water were subjected to 20 minutes of ultrasonic vi b r a t i o n at an i n t e n s i t y of 80 on the control. The samples were cooled i n a water bath. The temperature was kept below 30°C. This method was found to be optimum for dispersion of the complexes [personal communication, A. Hinds, Ph.D. student, U.B.C.]. The samples upon dispersion were wet sieved to pass a 270 mesh sieve (<53u). The remaining suspension was subjected to centrifugat with a Sharpies Supercentrifuge {continuous flow) at a flow rate of 1850 ml/min and a speed of 5000 rpm. The s i l t (50-2y) f r a c t i o n was retained upon the l i n e r while the clay remained i n suspension. The s i l t was separated i n t o f i n e (20-2y) and coarse (50-20u) s i l t by gravity sedimen-tation [Jackson, 1956]. The clay suspension was again subjected to the Sharpies Supercentrifuge at a flow rate of 200 ml/min and a speed of 17,000 rpm i n order to separate the f i n e (<0.2u) and coarse (2-0.2u) clays. The coarse clay was collected from the l i n e r while the f i n e clay was flocculated with CaCl,,. A l l samples were subjected to centrifugation to concentrate the sample and then freeze dried for storage and subsequent use. 2000 LL 50>L 20LI 5)i 2ju 0.2M 0.08M SAND iCOARSt SILT MED. SILT f. SILT COARSE CLAY MED. CLAY FINE CLAY U.S.D.A. SIZE FRACTIONS FOR PHYSICAL ANALYSIS 2 0 0 0 M 200M COARSE SAND 20 LL FINE SAND SILT 0.2 >i C O A R S E C L A Y FINE C L A Y I N T E R N A T I O N A L ( A T T E R B E R G ) S I Z E F R A C T I O N S 2000LL S A N D 50ju C O A R S 2pM S I L T E F I N E 2.M — T K " 0 . 2 M C L A Y C O A R S E F I N E S I Z E F R A C T I O N S U S E D F O R O R G A N O - M I N E R A L S T U D Y Figure 1 Comparison of U.S.D.A. and International size fractions to those used for the organo-mineral study 81 The clay and s i l t fractions were separated at the above l i m i t s i n order to obtain r e l a t i v e l y broad classes of separates. Finer separa-tions would have been d i f f i c u l t since p a r t i c l e densities d i f f e r in rel a t i o n to the amounts of organic matter adsorped unto the p a r t i c l e s . The separation into these s p e c i f i c size l i m i t s allows extrapolation between the U.S.D.A. and the International (Atterberg) l i m i t s f o r p a r t i c l e s i z e (Figure 1). The p a r t i c l e s i z e d i s t r i b u t i o n was determined gravimetrically after each f r a c t i o n was separated and freeze dried. The sand f r a c t i o n was determined by difference. The surface area of the mineral f r a c t i o n was determined using the ethylene glycol monoethyl ether (E.G.M.E.) adsorption method [Heilmon et a1_., 1965]. The organic matter for this procedure was destroyed by sodium hypochlorite (NaOCl) at pH 9.5 [Anderson, 1963; Lavkulich and Weins, 1970] using four successive treatments. Determination of t o t a l carbon for s o i l s and complexes was carried out by dry combustion using a high temperature induction furnace [ A l l i s o n et al_., 1965]. The percent organic matter was estimated by use of the m u l t i p l i c a t i o n factor of 1.724. Total nitrogen was determined by semi-micro-Kjeldahl digestion and the ammonium nitrogen r e s u l t i n g from t h i s digestion was determined colo u r i m e t r i c a l l y according to the method of Beecher and Witten [1970]. Exchangeable cations were determined by displacement with ammonium acetate (IN NH^OAc) at pH 7.0 and centrifugation to separate the supernatant l i q u i d from the s o l i d sample. 82 The binding or bridging cations were determined by f i r s t saturating the complexes with ammonium acetate to displace the exchangeable cations at pH 7.0. Samples were then subjected to four successive sodium hypochlorite treatments (pH 9.5) saving the extracts. Samples were then washed twice with IN amononium acetate pH 7.0 to displace the remaining cations from sample. Cations were determined by atomic absorption spectroscopy. Sodium pyrophosphate (0.1 M Na^Oy, pH 10.0) was used to extract the organically bonded Fe and Al [McKeague, 1967; Bascomb, 1968]. Ca, Mg and Mn were also determined on th i s extract. RESULTS AND DISCUSSION The investigation of the d i s t r i b u t i o n of the organic substances i n r e l a t i o n to s o i l separates aids in understanding the relationship between the organic and inorganic fractions in s o i l s . Looking at the d i s t r i b u t i o n of the s o i l separates without destroying the organic matter one sees a somewhat distorted p a r t i c l e size d i s t r i b u t i o n . Compared to the "normal p a r t i c l e s i z e " d i s t r i b u t i o n [Broerma, 1973b] the amount of < 2u material has increased considerably. This i s largely the resul t of the high amounts of organic matter associated with each p a r t i c l e causing a decrease i n the "natural" p a r t i c l e density. A l l separates were determined by using a p a r t i c l e density of 2.65 grams per cubic centimeter. Thus the overall p a r t i c l e density i s lower because of the associated organic matter with the mineral grains. The whole d i s t r i b u t i o n of the separates i s shifted towards the f i n e r fractions due to t h e i r close association with the organic matter. The granulometric composition of these s o i l s i s typical for the coarse textures that were observed (Table 1). The t o t a l sand fra c t i o n amounts to over 40 percent of the to t a l s o i l (<2 mm) except for s i t e 2 and 4 which are 35.9 and 34.0 percent sand, respectively. At s i t e s 2 and 4 the content of coarse s i l t i s considerably higher than at any other s i t e . The bulk of the separates of the clay and s i l t fractions i s found i n the fine s i l t . The total fine clay amounts to less than 1.8 percent of the t o t a l separates. The d i s t r i b u t i o n of the organic matter on a whole s o i l shows some inter e s t i n g trends (Table 1). The f i n e s i l t f r a c t i o n accounts for 40-60 percent of the t o t a l organic matter while i t constitutes about 20-30 percent of the s o i l separates, except for s i t e 7, where the fi n e s i l t f r a c t i o n accounts for only 25 percent of the t o t a l organic matter and i s associated with 18 percent of the to t a l separates. The coarse clay which constitutes 5-15 percent of the t o t a l s o i l separates accounts for about 20-40 percent of t o t a l organic matter. The fine clay which amounts to less than 1.8 percent of the s o i l accounts for 4-8 percent of the to t a l organic matter. I t can be seen from t h i s d i s t r i b u t i o n that the bulk of the organic matter i n most of these surface horizons i s associated with the fine s i l t and coarse clay, but that appreciable amounts of organic matter are also associated with the other fr a c t i o n s . The organic matter i n the sand fractions are in most cases p a r t i c l e s of organic matter rather than coatings or fi l m s . . TABLE 1 Dis t r i b u t i o n of Organo-Minerals Complexes and Organic Matter 9 2000 - 50 \i 50 - 20 y 20 - 2 u 2 - 0.2 y <0.2 u Horizon Depth(cm) O.M. O.M. % C.Si.' % O.M. f .Si O.M. % cc. % O.M. % Ah 1 Ah 2 Ah Ah Ah 1 Ah 2 0-15 15-28 0-20 0-10 0-18 18-36 SITE 1 4.6 2.9 58.0 63.7 1.9 7.2 7.4 8.2 SITE 2 3.6 35.9 8.6 20.0 SITE 4 0.5 34.0 25.0 25.2 SITE 5 1.0 2.7 49.2 61.2 4.4 3.9 8.5 8.4 based on whole s o i l (<2 mm) d F i n e S i l t 'Sand 'Coarse Clay 61.3 54.6 49.9 38.7 49.5 57.6 25.5 20.7 28.1 27.9 8.1 6.2 29.5 32.7 12.9 24.9 31.5 14.0 27.3 21.6 39.6 28.7 13.2 7.4 Coarse S i l t fFine Clay 4.1 7.5 5.9 4.4 5.4 7.2 1.0 1.2 1.8 1.6 1.7 1.4 TABLE 1 (continued) 2000 - 50 y 50 - 20 y 20 - 2 y 0.2 y <0.2 y Horizon Ah 1 Ah 2 Ah 3 Ah Depth(cm) 0-10 10-23 23-33 0-10 9.1 11.4 4.7 7.3 O . M . 62.1 64.1 70.0 43.5 C.Si. SITE 6 8.9 15.8 9.4 4.5 10.0 7.6 SITE 7 32.4 23.3 O . M . 56.0 44.3 52.8 24.7 f.Si 23.6 19.3 16.4 17.6 O . M . 29.9 24.1 26.6 32.1 CC. 8.3 6.3 5 . 0 14.3 O . M . % 5.3 4.6 6.4 3.6 f. c. % 1.4 1.1 1.0 1.3 based on whole s o i l (<2 mm) JFine S i l t Sand 'Coarse Clay Coarse S i l t f Fine Clay CD c n In Table 2 data i s presented on the relationship between the amount of organic matter and the surface area of the separates, expressed in grams of organic matter per centimeter squares of surface. I t i s interesting to note that the amount of organic matter 2 associated with one cm i s rather constant. In the fine clay f r a c t i o n -7 2 this ranges between 3.2 and 7.5 x 10 grams ofO.M. /cm for the extremes. In the coarse clay f r a c t i o n the range, is from 3.6 to 9.6 x 10"^ grams o of O.M./cm , while in the fine s i l t f r a c t i o n the range i s 3.8 to 16.6 x -7 2 10 grams of 0.M/cm and i n the coarse s i l t f r a c t i o n the range i s -7 2 from 6.1 to 14.8 x 10 grams of O.M. /cm , except for s i t e 7 coarse -7 2 s i l t which has a value of 30.6 x 10 grams of O.M./cm . The averages for f i n e c l a y , coarse clay, f i n e s i l t and coarse s i l t are 5.0, 5.7, -7 2 8.8 and 9.7 x 10 grams of O.M./cm, respectively. I t can be seen that the to t a l amount of organic matter per centimeter square increases as the surface area decreases. The high amount of organic matter associated with the coarse s i l t of s i t e 7 could be explained in that some of the organic matter i s present as discrete p a r t i c l e s rather than as films or coatings. Low power optical microscopic observations of the d i f f e r e n t fractions showed(Figure 2a) that the coarse and fine s i l t had many pa r t i c l e s of organic matter as well as coatings. This was especially apparent in the coarse s i l t of s i t e 7. The coarse clay showed a more even d i s t r i b u t i o n of organic matter on surfaces. The fine clay showed a very fine granular structure (Figure 2b)that had to be crushed before single grains could be observed. Upon crushing the fine clay showed the organic matter as evenly distributed upon the p a r t i c l e s . T A B L E 2 2 Surface Area of Inorganic Separates and the Quantity of Organic Matter Distributed per cm of Surface Area 50 - 20ya 20 -2p b 2 - 0.2uc <0.2u Horizon Depth(cm) Surface Area cmz/g x 104 g O.M./cm x 10"7 Surface Area cn^ /g x 10* g O.M./cmZ x 10"7 Surface Area . cm2/g x 10* g O.M./cm2 x IO7 Surface Area . cn)2/g x 10* g O.M./off x 10"7 S I T E 1 Ah 1 Ah 2 0-15 15-28 5.3 8.1 6.1 7.9 59.8 59.9 S I T E 2 7.0 3.8 116.9 110.2 6.4 4.1 205.7 143.8 4.8 5.2 Ah 0-20 7.9 8.8 41.5 S I T E 4 8.2 115.8 4.0 182.4 5.4 Ah 0-10 15.4 14.2 24.0 S I T E 5 16.2 81.2 8.4 186.3 5.2 Ah 1 Ah 2 0-18 18-36 6.8 4.3 11.7 7.8 31.0 41.7 S I T E 6 11.2 5.6 130.2 105.4 5.7 3.6 216.2 151.3 3.2 3.8 Ah 1 Ah 2 Ah 3 0-10 ' 10-23 23-33 26.6 23.3 13.0 14.8 9.4 6.5 31.0 39.5 47.9 S I T E 7 16.6 9.1 5.3 152.7 81.8 116.8 7.0 9.6 4.3 177.2 124.6 144.2 6.6 7.5 4.7 Ah 1 0-10 7.8 30.6 46.6 ) 5.2 123.2 3.6 167.3 3.7 aCoarse si lt Fine si lt cCoarse clay Fine Clay 88 Figure 2a Presence of free organic matter in the fine s i l t of s i t e 7 89 Figure 2b Granulation of the fine clay as a result of freeze drying 90 The data and trends observed in Table 2 are very s i m i l a r to those found by Alexandrova e_t al_. [1964]. The d i s t r i b u t i o n of organic matter in the mineral fraction i s in the form of coatings or films with the quantity of organic matter being determined by the amount of surface area except for particles in the coarser fra c t i o n s . In Table 3 the relationship between tota l carbon and total nitrogen i s expressed on a whole s o i l basis and the four separates under study: coarse s i l t , fine s i l t , coarse clay and fine clay. The tot a l carbon and nitrogen of the four separates are considerably higher than the whole s o i l . This i s especially apparent f o r the clay-complexes which are from 3 to 7 times as high. The C/N r a t i o increases as the p a r t i c l e size increases. An increase of the C/N r a t i o can also be observed as one progresses from s i t e 1 to s i t e 7. This trend i s more apparent in the s i l t fractions and the whole s o i l than i t is i n the clay f r a c t i o n s . This increase in the C/N r a t i o i s the re s u l t of the d i f f e r e n t types of organic matter found at the di f f e r e n t s i t e s , as well as, the di f f e r e n t rates of decomposition of these d i f f e r e n t types of organic matter. The C/N r a t i o of the Douglas f i r organic matter i s much higher (<50) than that of Garry oak (20-50) or that of grasses (10-20) [Cruickshank, 1972]. The increase of the C/N r a t i o of each set of separates i s the re s u l t of the degree of decomposition associated with each f r a c t i o n . The coarse s i l t i s associated with organic matter that has not decomposed to any s i g n i f i c a n t degree as can be seen from the wide C/N r a t i o . The f i n e r the fr a c t i o n the narrower the C/N r a t i o due to a more complete decomposition of the organic tissues. Also the organic matter associated with the f i n e r 91 TABLE 3 Total Carbon, Total Nitrogen and the C/N Ratios for Complexes and Whole Soi l Horizon Depth(cm) Fraction %C %N C/N SITE 1 Ah 1 0-6 W.S.a 7.0 0.57 12.35 f . c . D 28.7 3.58 8.02 c c . , 24.7 2.19 11.28 f . s i . d 17.1 1.20 14.25 Ah 2 c . s i . 1.8 0.12 15.00 6-11 W.S. 4.3 0.37 11.76 f.c. 24.7 2.94 8.40 C.C 17.9 1.94 9.23 f . s i . 10.5 1.08 9.72 c . s i . 3.5 0.28 12.50 SITE 2 Ah 1 0-8 W.S. 9.6 0.76 12.65 f.c. 28.7 3.10 9.26 C.C 22.3 1.77 . 12.60 f .so. 14.7 0.72 20.42 c . s i . 3.8 0.25 15.20 SITE 4 Ah 1 0-4 W.S. 10.1 0.89 11.29 f.c. 28.5 3.43 8.31 C.C. 23.6 2.41 9.79 f . s i . 16.3 1.55 10.52 c . s i . 10.4 1.04 10.00 SITE 5 Ah 1 0-7 W.S. 8.1 0.56 14.96 f.c. 26.2 2.59 10.12 C.C. 24.7 1.99 12.41 f . s i . 14.9 1.24 12.02 Ah 2 c . s i . 4.3 0.34 12.65 7-14 W.S. 3.8 0.20 19.15 f.c. 21.1 2.92 7.23 c c . 16.0 1.71 9.36 f . s i . 11.0 0.95 11.58 c . s i . 1.9 0.16 11.88 92 TABLE 3 (continued) Horizon Depth(cm) Fraction %C %N C/N SITE 6 Ah. 1 0-4 W.S. 9.5 0.69 13.71 f .c. 31.2 2.45 12.73 c. c. 30.0 2.11 14.22 f . s i . 19.7 0.95 20.74 Ah 2 c . s i . 16.4 0.85 19.76 4-9 W.S. 6.9 0.40 17.25 f .c. 28.1 2.56 10.98 c c . 25.5 1.89 13.49 f . s i . 15.3 1.05 14.57 Ah 3 c . s i . 10.4 0.42 24.76 9-13 W.S. 3.6 0.28 12.80 f .c. 23.5 2.22 10.56 c c 19.4 1.51 12.85 f . s i . 11.8 0.83 14.22 c . s i . 4.5 0.25 18.00 SITE 7 Ah 1 0-4 W.S. 8.0 0.40 20.13 f . c 22.1 1.84 12.01 c c 18.1 0.90 20.11 f . s i . 11.3 0.54 20,93 c . s i . 11.2 0.44 25.45 aWhole s o i l <2 mm bFine clay <0.2y cCoarse clay 0.2-2y dFine s i l t 2-20y eCoarse s i l t 20-50y i s more stable. Once the organic matter i s associated with the inorganic f r a c t i o n ; the f i n e r the f r a c t i o n the less l i k e l y i t i s that the organic matter w i l l be released. Thus the clay fractions are associated with organic matter that i s more stable in that i t has decomposed to such a degree that the rate of release of C and N i s the same thus giving a r e l a t i v e l y constant C/N r a t i o of 8 to 12 for the fine clay. In Tables 4 and 5 are given the exchangeable cations and the "binding cations" respectively. Among the proposed mechanisms f o r the formation of organo-mineral complexes the cation bridge model i s believed to best i l l u s t r a t e the bonding mechanism [Greenland, 1965a; Scharpenseel, 1967; Alexandrova, 1967]. The cation bridge i s necessary ' order to bind the negatively charged organic matter with the negatively charged inorganic f r a c t i o n . In chernozemic s o i l s the predominant binding or bridging cation i s calcium, while iron i s considered to be the important homologue in more highly weathered s o i l s [Scharpenseel, 1967]. I t was thought that the importance and d i s t r i b u t i o n of these binding cations could be studied by chemical displacement and extraction. In Table 4 are shown the results of the exchangeable cations being displaced from the complexes in order to prevent them from being considered with the binding or bridging cations. The cations were displaced by ammonium ions (Nrfjp using IN NH^OAc at pH 7.0.. Calcium could not be determined for the fine clay f r a c t i o n because this f r a c t i o n had been previously flocculated by calcium chloride (CaC^). The dominant exchangeable cation was found to be calcium which was present at l e a s t f i v e times magnesium. Potassium and sodium 94 TABLE 4 Exchangeable Cations of the Complexes and the Whole S o i l Site and Horizon Fraction of So i l Exchangeable Cations me/100 gr Ca Mg K Na SITE 1 Ah 1 W.S. 12.00 2.56 0.28 0.26 f.c. - 0.73 0.48 0.13 c. c. 37.77 7.48 0.45 0.33 f . s i . 33.24 6.85 0.26 0.08 Ah 2 c . s i . 3.88 0.53 0.08 0.09 W.S. 8.00 1.40 0.16 0.96 f.c. - 0.47 0.39 0.33 c. c. 36.12 5.44 0.38 0.17 f . s i . 21.44 3.43 0.24 0.10 c . s i . 8.44 1.21 0.11 0.14 SITE 2 Ah 1 W.S. 1.50 0.22 0.32 0.14 f.c. - 0.29 0.47 0.41 c c . 5.15 0.62 0.46 0.36 f . s i . 4.13 0.42 0.31 0.27 c . s i . 1.68 0.16 0.17 0.10 SITE 4 Ah 1 W.S. 2.26 0.32 0.20 0.20 f.c. - 0.21 0.28 0.23 c. c. 6.73 1.07 0.34 0.35 f . s i . 5.63 0.46 0.18 0.11 c . s i . 4.20 0.33 0.12 0.06 SITE 5 Ah 1 W.S. 16.50 3.60 0.34 0.46 f.c. - 0.66 0.42 0.16 c c 58.58 10.68 0.36 0.26 f . s i . 38.67 7.13 0.23 0.09 Ah 2 c . s i . 10.43 1.59 0.10 0.04 W.S. 8.00 1.60 0.18 0.16 f.c. 36.82 0.46 0.27 0.29 c c 6.17 0.37 0.19 f . s i . 23.32 3.92 0.22 0.13 c . s i . 4.10 0.64 0.10 0.25 95 TABLE 4 (continued) Site and Horizon Fraction of S o i l Exchangeable Cations me/100 gr Ca Mg K Na SITE 6 Ah 1 W.S. 15.50 3.26 0.56 0.30 f.c. - 0.28 0.38 0.26 C.C. 50.02 8.18 0.31 0.18 f . s i . 32.69 5.54 0.27 0.09 c . s i . 24.21 4.68 0.22 0.30 Ah 2 W.S. 10.00 1.86 0.34 0.50 f.c. - 0.28 0.28 0.23 C.C. 37.67 5.18 0.24 0.29 f . s i 23.32 3.45 0.26 0.32 c . s i . 14.24 2.00 0.17 0.13 Ah 3 W.S. 6.50 0.90 0.16 0.20 f.c. - 0.20 0.13 0.38 C.C. 27.58 3.21 0.29 0.25 f . s i . 19.94 2.01 0.24 0.23 c . s i . 7.28 0.77 0.12 0.18 SITE 7 Ah 1 W.S. 13.00 2.80 0.60 0.30 f.c. - 0.46 0.55 0.47 C.C. 32.53 5.20 0.66 0.23 f . s i . 24.95 3.66 0.31 0.20 c . s i . 17.77 2.74 0.24 0.13 were present i n roughly the same proportion but considerably lower than magnesium. This relationship also existed in the measurements of the whole s o i l . In general i t can be observed that with increasing p a r t i c l e size there i s a decrease in the to t a l exchangeable cations. This i s to be expected since coarser fractions have less surface area, as well as, considerably less organic matter. The coarser fractions have a much lower exchange capacity. The t o t a l exchangeable cations for the fine clay-organo complexes are much lower than expected, since they are considerably lower than observed for the coarse clay complexes. This could well be due to the methodology of preparing the organo-mineral complexes. Freeze drying seemed to cause a granulation especially of the f i n e clay (Figure 2b). The coarse clay complexes were only p a r t i a l l y granulated and only very weakly. The s i l t complexes were powdery a f t e r freeze drying. The granulation of the fine clay complexes could render them quite r e s i s t a n t to mild chemical action. The loss of exchangeable cations due to ultrasonic treatment is quite low. Conductivity measurements before and af t e r sonic tr e a t -ments were not very d i f f e r e n t . I t i s in t e r r e s t i n g to note that the calcium and magnesium content i s very much less in s i t e s 2 and 4 than i n any other s i t e . This i s especially apparent i n the clay-organo complexes. The determination of the "binding cations" was undertaken by destruction of organic matter by sodium hypochlorite (NaOCl) at pH 9.5 as outlined by Anderson [1963]. The use of NaOCl pH 9.5 has been shown to be more sel e c t i v e i n the destruction of organic matter while causing minimal destruction of the mineral constituents compared with hydrogen peroxide (F^G^) used conventionally [Lavkulich and Wiens, 1970]. Most cation bridging studies i n r e l a t i o n to organo-mineral complexes were determined s y n t h e t i c a l l y . The use of natural organo-mineral complexes makes these studies more d i f f i c u l t . I't was thought that by using NaOCl pH 9.5 as a selective extractant f o r organic matter a study of the binding cations in r e l a t i o n to t h e i r proportions and d i s t r i b u t i o n could be made more meaningfully. I t must be remembered that such an extraction also includes cations present i n the organic matter that are not d i r e c t l y involved i n bridging but they cause an overall decrease i n the negative charge of the organic matter. Sites 2 and 4 again show very low contents of calcium and magnesium. The calcium content only amounts to a trace amount. The Al content on the complexes of s i t e 2 and 4 are somewhat higher. The determination of iron according to th i s method could be i n error because of the high pH. The s o l u b i l i t y of iron above pH 9.0 i s very low [Loughnan, 1969] so that a l l the iron present might not be in solution. The use of 0.1 N sodium pyrophosphate (Na^Oy) pH 10.0 as an extractant for organo-irdn and organo-aluminum i s very common [Bascomb, 1968; McKeague, 1967; Kononova and Bel'chikova, 1970]. This extraction appears to be quite s p e c i f i c for organically bound iron and aluminum e s p e c i a l l y , but other cations are also complexed. [Kononova and Bel'chikova, 1970] Pyrophosphate does not extract appreciably the inorganic amorphous or c r y s t a l l i n e iron or aluminum [Schwertmann, 1973; McKeague, 1967]. Sodium pyrophosphate has been found to extract iron Amounts of TABLE 5 Binding and Bridging Cations Horizon S o i l Fraction Al Fe Ca Mg Mn Cu Zn % .— ppm SITE 1 Ah 1 f.c. 0.40 0.09 0.19 168 297 465 137 c. c. 0.24 0.06 0.31 181 227 232 64 f . s i . 0.30 0.07 0.10 63 90 78 40 c . s i . 0.05 0.01 0.01 18 23 18 16 Ah 2 f. c. 0.36 0.05 0.13 86 381 238 76 c. c. 0.34 0.04 0.10 65 149 189 40 f . s i . 0.23 0.03 0.06 44 110 55 17 c . s i . 0.06 0.02 0.01 22 43 30 15 SITE 2 Ah 1 f.c. 0.50 0.02 t r . * 34 339 356 51 c c . 0.48 0.05 t r . 33 329 258 56 f . s i . 0.43 0.03 t r . 31 123 196 43 c . s i . 0.12 0.01 t r . 24 0 49 31 SITE 4 Ah 1 f.c. 0.55 0.05 t r . 42 938 250 104 c c . ' 0.51 0.07 t r . 31 398 146 44 f . s i . 0.41 0.04 t r . 30 396 73 23 c . s i . 0.20 0.02 t r . 50 239 43 45 SITE 5 Ah 1 f.c. 0.33 0.09 0.23 226 0 491 94 c. c. 0.22 0-07 0.27 69 343 304 59 f . s i . 0.31 0.11 0.10 60 167 110 37 c . s i . 0.07 0.03 0.01 24 0 29 22 TABLE 5 (continued) Horizon S o i l Fraction Al Fe Ca Mg Mn Cu Zu % ppm SITE 5 (continu ed) Ah 2 f.c. 0.28 0.04 0.13 81 202 242 61 c c . 0.29 0.04 0.11 78 0 150 29 f . s i . 0.24 0.04 0.07 33 119 95 21 c . s i . 0.05 0.01 0.01 27 0 29 20 SITE 6 Ah 1 f.c. 0.43 0.08 0.19 59 198 238 99 c c . 0.47 0.22 0.14 73 585 268 68 f . s i . 0.38 0.08 0.06 49 486 70 33 c . s i . 0.27 0.06 0.08 43 1273 72 36 Ah 2 f.c. 0.38 0.06 0.18 48 385 250 77 c c . 0.51 0.09 0.08 65 700 215 70 f . s i . 0.41 0.06 0.05 54 1011 92 33 c . s i . 0.21 0.03 0.03 45 637 45 29 Ah 3 f.c. 0.14 0.01 0.15 33 165 159 27 c c 0.32 0.02 0.06 72 431 287 67 f . s i . 0.23 0.02 0.04 39 194 107 26 c . s i . 0.09 0.01 0.01 7 1129 42 9 SITE 7 Ah 1 f.c. 0.32 0.05 0.15 47 1495 215 103 c c 0.34 0.10 0.07 59 784 201 54 f . s i . 0.38 0.09 0.02 43 495 92 46 c . s i . 0.25 0.05 0.02 30 731 50 18 * t r . trace 100 and aluminum from the mineral s o i l i f montmorillonite i s present [Kononova and Bel'chikova, 1970]. In Table 6 the results of the pyrophosphate extractions are given. The results for calcium, magnesium and magnanese are given in addition to the normal iron and aluminum in order to compare the results to the exchangeable and binding cations previously determined. Table 5 gives the amounts of binding or bridging cations determined. Na and K could not be determined by t h i s method because of t h e i r presence i n the sodium hypochlorite reagent. The binding cations are present in the order of most to least as: Al > Ca > Fe > Mn > Cu > Zn = Mg. The amount of each cation generally increases with decreasing size of the organo-mineral f r a c t i o n s , except for some e r r a t i c trends with respect to manganese. The fine clay-organo complexes have about the same amount of binding cations as the coarse clay-organo complexes. This could be the re s u l t of the freeze drying forming hard granular p a r t i c l e s which are r e s i s t a n t to the chemical action of hypochlorite (Figure 2b). The f i n e clay organo-complexes contain the highest amount of extractable iron and aluminum. This f r a c t i o n contains roughly 3 to 4 times as much extractable iron and aluminum than the whole s o i l . Observing a l l the fractions i t can be seen that there i s a decrease in the amount of extractable iron and aluminum as the f r a c t i o n size increases. Sites 2 and 4 show very low amounts of calcium and magnesium. The iron and aluminum extractions, on the other hand, are somewhat higher than observed for the other s o i l s . Thus the bridging or binding TABLE 6 Sodium Pyrophosphate (Na 4P 20 7 0.1M pHlO.O) Extraction of A l , Fe, Ca, Mg, and Mn Horizon Soi l Fraction %A1 %Fe %Ca %Mg %Mn < SITE 1 Ah 1 W.S. 0.47 0.20 _ f.c. 1.93 1.42 a 0.070 0.009 C.C. 1.41 0.92 0.089 0.264 0.076 f . s i . 0.92 0.54 0.107 0.227 0.053 c . s i . 0.14 0.08 0.011 0.024 0.001 Ah 2 W.S 0.49 0.17 - - -f.c. 2.75 1.58 a 0.080 0.018 C.C. 2.20 1.18 0.028 0.086 0.026 f . s i . 1.34 0.66 0.031 0.073 0.015 c . s i . 0.23 0.13 0.027 0.034 0.010 c 5ITE 2 Ah 1 W.S. 1.33 0.20 _ f.c. 4.38 1.94 a; 0.044 0.157 c. c 2.90 0.70 <0.01 0.007 0.099 f . s i 2.13 0.38 <0.01 0.011 0.034 c . s i . 0.44 0.09 <0.01 0.003 0.007 >ITE 4 Ah 1 W.S. 1.14 0.27 _ f.c. 3.81 2.10 a 0.060 0.253 c c . 2.73 0.93 <0.01 0.018 0.201 f . s i . 1.51 0.39 <0.01 0.008 0.043 c . s i . 0.90 0.24 <0.01 0.006 0.046 S ITE 5 Ah 1 W.S. 0.46 0.24 _ _ f.c. 3.26 1.36 a 0.076 0.012 c c 0.78 0.52 0.083 0.199 0.033 f . s i . 0.72 0.48 0.153 0.234 0.052 c . s i . 0.09 0.09 0.041 0.045 0.007 Ah 2 W.S. 0.55 0.20 - _ f.c. 4.36 1.89 a 0.070 0.022 c c 2.62 1.37 0.036 0.116 0.030 f . s i . 1.09 0.52 0.027 0.069 0.014 c . s i . 0.14 0.08 0.017 0.021 0.003 1 102 TABLE 6 (continued) Horizon Soi l Fraction %A1 %Fe %Ca %Mg %Mn Ah 1 Ah 2 Ah 3 Ah 1 W.S. f.c. C.C. f . s i c.si W.S. f.c. C.C. f . s i c.si W.S. f.c. C.C. f . s i , c . s i , W.S. f.c. C.C. f . s i c.si SITE 6 0.49 1.83 1.46 0.77 0.70 0.52 2.39 2.13 1.08 0.74 0.83 3.89 3.05 1.71 0.69 0.65 2.38 1.66 0.86 0.58 0.18 1.20 1.05 0.35 0.34 0.18 69 10 0.45 0.33 0.21 1.67 1.08 0.58 0.22 SITE 7 0.27 1.71 1.14 0.43 0.28 a 0.068 0.095 0.088 a 0.026 0.028 0.026 a 0.010 0.010 <0.01 a 0.026 0.045 0.046 0.051 0.232 0.102 0.099 0.054 0.090 0.067 0.044 0.028 0.039 0.028 0.014 0.064 0.093 0.089 0.069 0.045 0.221 0.117 0.269 0.134 0.225 0.062 0.150 0.113 0.086 0.028 0.025 0.171 0.338 0.120 0.218 f . c l i s calcium chloride flocculated unavailable 103 cations of these two sites are dominated by Al and Fe. The extractions by pyrophosphate have resulted in much higher amounts of sesquioxides, than with hypochlorite. This i s especially apparent for Fe. The Ca, Mg, and Mn extracted by th i s method i s much lower even though the exchangeable cations had not been displaced. Pyrophosphate extraction i s not a good indicator of the amounts of other cations associated with the organic matter and i s therefore only an indicator for Al and Fe. CONCLUSIONS From the data on the d i s t r i b u t i o n of organic matter in r e l a t i o n to the inorganic f r a c t i o n (Tables 1 and 2) i t was found that a large amount of the organic matter was associated with the coarser fractions The f i n e silt-organo complexes accounted for 40 to 60 percent of the to t a l organic matter while i t constituted only about 20 to 30 percent of the to t a l separates. The coarse clay-organo complexes constitute 5 to 15 percent of the t o t a l s o i l separates and account for 20 to 40 percent of the t o t a l organic matter. This shows that a considerable portion of the complexed organic matter i s found within the coarser f r a c t i o n when amounts of clay materials are low. McKeague [1971] also observed t h i s when studying organic matter to inorganic matter relationships i n Ah horizons of a variety of s o i l s . Most previous studies have dealt only with organic matter associated with the clay fractions [Greenland, 1965; Dudas and Pawluk, 1969; Parasher and Lowe, 1970]. Studies of the combinations of organic matter 104 and inorganic s o i l constituents should include the coarser fractions as well as the clay. The importance of organic matter i n the coarser fractions i s also shown by the d i s t r i b u t i o n of organic matter in r e l a t i o n to surface area. I t was found that the weight of organic matter per unit of surface increased with increasing size of s o i l separates. This was also observed by Alexandrova et^ al_. [1964]. The coarser fractions were found to be associated with organic matter that had not been decomposed appreciably as was indicated by the higher C/N ratios for these fractions. Optical microscopic observations indicated that the organic matter associated with the coarser fractions was present as coatings as well as dark brown to black p a r t i c l e s . The f i n e r fractions with t h e i r Tower C/N r a t i o showed a more even d i s t r i b u t i o n of the organic matter as films or coatings. The binding or bridging of the organic matter to the inorganic matter appears to be mainly by A l , Fe and Ca i n these s o i l s . The bridgings are dominated by Al according to both the hypochlorite and pyrophosphate extractions. The Fe i s greater than Ca in the pyrophosphate extract while the reverse holds f o r the hypochlorite extract probably because of the pH which is too high to s o l u b i l i z e Fe. The dominance of Al and Fe as the bridging cations indicate that the processes of s o i l formation tend to be podzolic [Brydon and Sowden, 1959; Scharpenseel, 1967; Alexandrova et al_., 1964]. The r e l a t i v e l y high amounts of Ca found i n the bridging s i t e s i s probably 105 due to the base cycling of the vegetation associated with these s o i l s [Rozhnova and Kasatkina, 1970; Yakushevskay, 1964]. The climate and vegetation associated with these s o i l s [Broersma, 1973a] are thought to be important factors in the formation of the organo-mineral complexes. The summer droughts cause the drying of the organic matter upon the mineral f r a c t i o n and thus developing films or.coatings which are somewhat more resistant to decay. 106 LITERATURE CITED 1. ALEKSANDROVA, L.N., 1967. Organomineral Humic Acid, Derivatives and Methods of Studying Them, Soviet Soil Science No. 7, pp. 903-913. 2. ALEXANDROVA, L.N., O.V. YURLOVA, L.V. LOBITSKAYA, 1964. The Dis t r i b u t i o n and the Composition of the Humus Substances and Their Organo-Mineral Derivatives in the Granulometric Fractions in Some Types of S o i l s , Intern. Congress of Soil Science, Bucharest, Romania. 3. 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BR0ERMA, K., 1973b. Dark S o i l s of the V i c t o r i a Area, Vancouver Island, II Some of the Physical, Chemical and Mineralogical Properties and Genesis, Masters Thesis, U.B.C. 10. BRYDON, J.E. and SOWDEN, F.J., 1959. A Study of the Clay-Hunus Complexes of a Chernozemic and Podzol S o i l , Can. J. of Soil Science, Vol. 39, pp. 136-143. 11. CRUICKSHANK, J.G., 1972. Soi l Geography, David and Charles Publishers, L.T.D., 1972. 107 12. DAY, P.R., 1950. Physical Basis of P a r t i c l e Size Analysis by the Hydrometer Method, Soil Science, Vol. 70, pp. 363-374. 13. DUDAS, M.J. and PAWLUK, S., 1969. Chernozemic Soils of the Alberta Parklands, Geoderma, No. 3, pp. 19-36. 14. EDWARDS, A.P. and BREMNER, J.M., 1964. Use of Sonic Vibrations for Separation of S o i l P a r t i c l e s , Can. J. Soi l S c i . , 44, p. 366. 15. GREENLAND, D.J., 1965a, Interaction Between Clays and Organic Com-pounds i n S o i l s . Part 1. Mechanics of Interaction Between Clays and Defined Organic Compounds, Soils and Fert.,Vol. XXVIII, pp. 4.5-425. 16. GREENLAND, D.J., 1965b. Interaction Between Clays and Organic Compounds in S o i l s . Part 2. Adsorption of Soi l Organic Compounds and Its Effect on Soi l Properties, Soils and Fert., Vol. XXVIII, pp. 521-532. 17. HEILMON, M.D., D.L. CARTER and C L . GONZALES, 1965. The Ethylene Glycol Monoethyl Ether (E.G.M.E.) Technique for Determining Soil Surface Area, Soil Science 100, pp. 409-413. 18. JACKS, G.V., 1963. The Biological Nature of Soi l Productivity, S o i l s and Fert., Vol. XXVI, No. 3, pp. 147-150. 19. JACKSON, M.L,, 1956. Soil Chemical Analysis - Advanced Course. Pub. by the author, Dept. of S o i l s , University of Wis., Madison. 6, Wis. 20. K0N0N0VA, M.M. and BELCHIK0VA, V.V., 1970. Use of Sodium Pyrophosphate to Separate and Characterize Organoiron and Organoaluminum Compounds in S o i l , Soviet So i l Sc., 1970, No. 6, pp. 61-74. 21. KITTRICK, J.A. and E.L. HOPE, 1963. A Procedure for the P a r t i c l e -Size Separation of So i l s f o r X-ray D i f f r a c t i o n Analysis, Soil Science, Vol. 96, pp. 319-325. 22. KYUMA, K., A. HUSSAIN, and K. KAWAGUCHI, 1969. The Nature of Or-ganic Matter in Soil Organo-Mineral Complexes, S o i l Science and Plant N u t r i t i o n , Vol. 15, No. 4, pp. 149-155. 23. LAVKULICH, L., and J.H. Wiens, 1970. Comparison of Organic Matter Destruction by Hydrogen Peroxide and Sodium Hypochlorite and Its Effects on Selected Mineral Constituents, So i l S c i . Soc. Amer. P r o c , Vol. 34, pp. 755-758. 108 24. ' LOUGHNAN, F.C, 1969. Chemical Weathering of the S i l i c a t e Minerals, Elsevier Publishing Co., New York. 25. McKEAGUE, J.A., 1967. An Evaluation of 0.1 M Pyrophosphate and Pyrophosphate-Dithionite in Comparison with Oxalate as Extractants of the Accumulation Products in Podzols and Some Other S o i l s , Can. J. S o i l , Science, Vol. 47, pp. 95-99. 26. McKEAGUE, 1971. Organic Matter in Pa r t i c l e - S i z e and Specific Gravity Fractions of Some Ah Horizons, Can. J. Soi l Science, 51, pp. 499-505. 27. PARASHER, CD. and L.E. LOWE, 1970. Isolation of Clay-Size Organo-Mineral Complexes from Soils of the Lower Fraser Valley, Can. J. Soi l Science, Vol. 50, pp. 403-407. 28. RODE, A.A., 1962. Soil Science (Trans, by. A. Gourwich), Israel Prog, f o r S c i . Trans., Jerusalem. 29. ROZHNOVA, T.A. and T.V. KASATKINA, 1970. Soi l s Forming Under Oak Forest in the Northwest, Soviet Soil Science, 1970, No. 9, . pp. 10-19. 30. SCHARPENSEEL, H.W., 1967. Tracer Investigations on Synthesis and Radiometric Conbination of S o i l Organo-Mineral Complexes, So i l Chemistry and F e r t i l i t y (ed. G.V. Jacks), International Society of Soi l Science, pp. 41-52. 31. SIMONSON, R.W., 1959. Outline-o f a Generalized Theory o f S o i l Genesis, Soil S c i . Soc. Am. P r o c , 23, pp. 152-156. 32. VOLOBUYEV, V.R., 1970. A System of Types of Soil Organo-Mineral Reactions, Soviet So i l Science, 1970, No. 3, pp. 18-31. 33. YAKUSHEVSKAY, I.V., 1969. Novgorod Oak Forest S o i l s , Soviet S o i l Science, 1964, No. 12, pp. 893-901. 109 SUMMARY The r e s u l t of the unique environmental factors are very important i n the formation of the sombric s o i l s . The vegetation along with i t s climate i s the main influence i n that the vegetation results i n an addition of organic matter that i s incorporated into the surface of the s o i l but does not decompose rapidly because of unfavourable clim a t i c conditions. The climate results i n only li m i t e d time when temperature and moisture are favourable for organic matter decomposition. The cool winters and very dry summers are the main adverse conditions for decomposition. The v a r i a b i l i t y of the parent materials which are mostly marine worked deposits are very s t r a t i f i e d making c l a s s i f i c a t i o n and pedologic processes d i f f i c u l t to understand. Due to the s t r a t i f i c a t i o n and v a r i a b i l i t y of the parent materials of these s o i l s chemical c r i t e r i a could not be used as the basis f o r c l a s s i f y i n g these s o i l s because of the lack of an 1C horizon. Also the high amounts of Fe and Al i n the surface which may have resulted from pre-weathering of s u r f i c i a l deposits p r i o r to present dry s o i l formation make c l a s s i f i c a t i o n of the s o i l s d i f f i c u l t . Thus c l a s s i f i c a t i o n of theses s o i l s has been on the basis of morphology mostly. The colour, structure, high surface weathering and the Ch/Cf r a t i o s indicate that these s o i l s were more s i m i l a r to Sombric Brunisols (Inceptisols) for s i t e s 1 to 6 while s i t e 7 was c l a s s i f i e d as an Sombric Podzol (Spodosol). S i t e 2 was extremely d i f f i c u l t to no c l a s s i f y since i t consisted only of an Ah horizon over bedrock. The high organic matter contents and the annual dessication due to the climate r e s u l t in the formation of organo-mineral complexes in the s i l t f r a c t i o n as well as the clay f r a c t i o n . The bulk of the organic matter was found to be associated with the fine s i l t and coarse clay f r a c t i o n s . The binding cation of the cation are dominated by Al and Fe with smaller amounts of Ca and Mg. This indicates that these s o i l s are not that s i m i l a r to Chernozems ( M o l l i s o l s ) i n which the dominant cations are Ca and Mg although the morphology would suggest t h i s . These Sombric are probably a t r a n s i t i o n between true chernozems and podzolized s o i l s . Although the studies were r e s t r i c t e d to the southern-most portion of Vancouver Island near V i c t o r i a but the data can be extra-polated by reference to Day et al_. [1959], to other parts of Vancouver Island and the Gulf Islands, Ugolini and Schlichte [1973] to Washington and Thilenius [1964] to^ the Willamette Valley, Oregon. 

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