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A study of the organic fraction of some British Columbia soils Cook, Fred Delmer 1947

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L t 3 /by  c ny fl* Cb 5?  A Study of the Organic Fraction of Some B r i t i s h Columbia Soils by Fred Delmer Cook -o 0 o-  A Thesis submitted i n P a r t i a l Fulfilment of The Requirements f o r the Degree of MASTER OF SCIENCE IN AGRICULTURE i n the Department of AGRONOMY (SOILS) -o 0 o-  The University of B r i t i s h Columbia  ACKNOWLEDGEMENTS  The author wishes to express h i s sincere appreciation t o Dr. D.G. L a i r d under whose guidance the work was conducted, and to Dr. C. Rowles f o r h i s h e l p f u l c r i t i c i s m s and suggestions.  TABLE OF CONTENTS. PART A.  Proximate Analysis of Organic Matter, of some B.C. S o i l s . Page  Review of L i t e r a t u r e  3 - 6  Description of S o i l s  6 -10  Experimental  11 -14  Discussion of Fractions  15 -16  Results and Discussion of Results  17 -25  Conclusions  25 -26  PART B.  Study of Lignin i n Organic Matter.  Review of. L i t e r a t u r e  27 -35  Experimental  35 -39  Discussion on Experimental  39 -4-3  Data and Discussion  43 -46  Hypoiodite Oxidation  46 -  5  0  Conclusions PART C.  Determination of S o i l Pigment i n some B.C. S o i l s .  Review of L i t e r a t u r e  52-54  Experimental  54-55  Data and Discussion  55-59  Conclusions Summary Bibliography  6  9. 61-62 6 3  "  6 8  A Study of the Organic F r a c t i o n of Some B r i t i s h Columbia Soils by Fred Delmer Cook*  ABSTRACT PART A.Carbon content, carbon-nitrogen r a t i o and a proximate analysis were determined on the organic matter of some representative B r i t i s h Columbia and Alberta zonal s o i l s .  Comparing s o i l zones carbon content and  hence percentage of organic matter was higher i n the A  Q  horizons of the Grey Wooded s o i l s while that i n the  A i horizons i s higher i n the Shallow Black and Transitional soils.  The carbon-nitrogen r a t i o was narrower i n  the grassland s o i l s .  Although proximate  analysis  did not show s t a r t l i n g differences between zones, certain differences seem to be s i g n i f i c a n t : (a) Higher " l i g n i n " nitrogen complex and l i p i d content i n P a c i f i c Coast and Grey Wooded s o i l s . (b) Percentages of "hemicellulose" and " c e l l u l o s e " decrease i n passing from the A  0  to the A^ horizon.  (o) "Lignin" and nitrogenous complexes concentrate i n the A^ horizons.  PART B.Nitrobenzene oxidation of s o i l organic matter from various sources yielded no c h a r a c t e r i s t i c oxidation products although excellent y i e l d s of v a n i l l i n and syringaldehyde were obtained from oxidation of spruce wood, f i r wood and rye straw.  I t i s suggested  that the groups involved i n the nitrobenzene  oxid-  ation reaction are destroyed during decomposition of plant materials, or that, some shortcomings i n techniqu were responsible for the i n a b i l i t y to i s o l a t e c h a r a c t e r i s t i c compounds. Hypoiodite oxidation of zonal s o i l s and t h e i r l i g n i n residues showed no consistant differences i n the nature of the l i g n i n .  Oxidation by hypoiodite i s  questioned as a means of detecting differences i n the constitution of the organic f r a c t i o n of B.C. s o i l s . PART C Relative humus colour i s shown to be higher i n the Shallow Black and T r a n s i t i o n a l s o i l s .  This  difference may be used as a c r i t e r i o n of s o i l type, Also the A^ horizons of a l l s o i l s examined show a higher humus colour value than the corresponding A  Q  horizon.  (1) INTRODUCTION. The c l a s s i f i c a t i o n of s o i l s i s based on a study of parent material, p r o f i l e development and t e x t u r a l grouping i n the f i e l d , and substantiated by chemical and physical analysis i n the laboratory. The chemical determinations f o r the most part, embrace a study of such phenomena as movement of sesquioxides, accumulation of s a l t s , base exchange and hydrogen ion concentration. The amount of organic matter i s also determined but no attempt i s made to determine the chemical nature of i t and r e l a t e the same to parent m a t e r i a l , climate, topography and s o i l forming processes. A detailed study of the organic f r a c t i o n of a s o i l should m a t e r i a l l y a i d the pedologist,since processes of s o i l formation and characterization are intimately t i e d i n with the chemical and physioal character of organic matter.  E x i s t i n g methods are admittedly inadequate but  despite t h i s , s p e c i f i c and interesting Information may be obtained from the application of a v a i l a b l e methods to a ciaemioal study of s o i l organic matter. The study herein reported was undertaken  i n order  to focus attention on the need f o r further work on the biochemistry of organic matter, to demonstrate differences i n the organic f r a c t i o n of zonal s o i l s as w e l l as of s o i l s  (2) within an association and to contribute something to the understanding of, or perfecting methods f o r f r a c t i o n a t i n g organic  residues.  The s o i l s studied are, f o r the most part, from the Central I n t e r i o r area of B r i t i s h Columbia and represent  s o i l s from the Shallow Black, Grey Wooded,  Black-Grey T r a n s i t i o n and P a c i f i c Coast s o i l zones. Typical Grey Wooded and T r a n s i t i o n a l s o i l s from Alberta are also included i n the study f o r purposes of comparison.  (3) PART A  PROXIMATE ANALYSIS Review of L i t e r a t u r e  L i t e r a t u r e r e l a t i n g to the physical properties and general chemical nature of organic matter i s very extensive while that pertaining to differences i n the chemical nature of the organic f r a c t i o n i n d i f f e r e n t s o i l s i s rather l i m i t e d .  Since the l i t e r a t u r e on  organic matter having general a p p l i c a t i o n has been f u l l y reviewed by Waksman (1938) the present  review  w i l l be confined to those references tnat concern d i r e c t l y or i n d i r e c t l y chemical differences between organic fractions of s o i l types. Schriener and Shorey (1910) using 2 per cent sodium hydroxide, alcohol and other solvents evolved a f r a c t i o n a t i o n procedure whereby they demonstrated differences i n carbon content between fresh and decomposing organic residues.  Shorey (1930) i n a review of methods  outlined a number of tests based upon the i s o l a t i o n of w e l l defined chemical compounds that could be applied to s o i l s i n order to bring out differences i n the organic f r a c t i o n . Pursulhlgs the question of differences between fresh and decomposed materials further, Bouyoucog  in  1934 described an ingenious method f o r determining the degree of decomposition  of organic matter.  H i s method i s  (4) based upon the r e l a t i v e v o l a t i l i t y of f r e s h and decomposed material i n a sealed bomb at 300° C. The amount of uronic carbon i n organic matter was  studied by Norman and Bartholomew (194-3) and they  found that the proportion of uronic a c i d increased with depth i n podsol s o i l s where a marked accumulation o f uronic carbon i s found i n the B. horizon. In recognizing t h i s observation they say, "Perhaps uronic acids are the *acids* often postulated but never proven to be the agents of cation t r a n s f e r i n the podsolization process."  Previously the o r i g i n  of uronic acids i n s o i l s has been discussed i n a highly t h e o r e t i c a l papat* by Waksman and Reuzer. ( 1 9 3 2 ) . A detailed study of the chemical nature of ammonium hydroxide extracts which involved acetylation, methylation was  and determination  of pQtentiometric  undertaken by Gillam ( 1 9 4 0 ) .  curves,  He i s l e d to the  conclusion that the humic acid f r a c t i o n o f every s o i l i s about the same chemically and appears to be oomposed o h i e f l y of l i g n i n . C r i t i c a l reviews on the methods o f determination of organio matter, organic oarbon and carbonates ane presented  by a number o f workers including Alexander and  Byers (1932),  Waksman and Stevens (1930),Schroer ( 1944•  The s o - c a l l e d proximate analysis proposed by the Russians and l a t e r modified and adapted t o American s o i l s  (5) by Waksman and Stevens (1930a) has been used extensively during the past decade f o r characterization of organic matter.  In f a c t , Waksman. (194-2) states that he  has  l i s t e d 87 d i f f e r e n t reports from workers that have used h i s modification of the proximate a n a l y s i s . t h i s method determines from 85% - 100% matter as " l i p i d s " , water soluble,  organic  "hemicellulose",  " c e l l u l o s e " , " l i g n i n s " and "protein." of Waksman*s procedure was  of the  In b r i e f ,  A modification  described by Vandecaveye and  Katznelson (194-0) i n which the percentage carbon removed by each f r a c t i o n a t i o n procedure was  determined.  This  modification has merit i n that no a r b i t r a r y factors or empirical determinations are involved. Recently the proximate analysis modified by Shewan (1938) has been used by Salisbury and De I» ng (194-0) 0  to compare organic matter i n v i r g i n and c u l t i v a t e d Quebec podsol s o i l s .  These workers found that "protein"  resistant to hydrolysis forms a s l i g h t l y l a r g e r proportion of the organic matter i n c u l t i v a t e d and pastured s o i l s , and that the "hemicellulose" content of the v i r g i n s o i l s i s higher than that of the c u l t i v a t e d and pastured s o i l s . Also, the " l i g n i n " content was  lower i n the l a t t e r s o i l s .  More recently, Gross (194-6) studied and characterized the forest f l o o r layers i n Northern Saskatchewan Grey Wooded soils.  Gross reports that no consistent differences were  (b) noted between, d i f f e r e n t forest f l o o r types i n regards to amount of " l i p i d s " and water soluble organic substances.  However i n granular mor.  types hemicelluloses  increase with decomposition of the l e a f l i t t e r whereas t h i s f r a c t i o n decreases with decomposition of the l i t t e r of other mor types.  For a l l forested types he found  a rapid decrease i n " c e l l u l o s e " content and a steady increase i n l i g n i n content with decomposition of the leaf l i t t e r . Description of the S o i l s A description of the s o i l associations and the horizon samples taken f o r analysis are presented i n Tables I and I I . Further information about these s o i l s , the general description of the area and the type of agriculture f o r the Central I n t e r i o r may be found i n Farstad and L a i r d (1945).  TABLE I  GENERAL INFORMATION ABOUT THE SOILS UNDER STUDY.  Association Name  Texture  Zone (Tentative)  Location  Topography  Native Vegetation.  Dawson  Clay  Shallow Black  Dawson Creek  Sloping 2-10%  Grasses and Poplar  ti  n  S.W. of Vanderhoof  Undulating  n  Bulkley Valley  R o l l i n g to h i l l y  n  Pinohi Lake  Undulating to rolling  Grasses  Holling to h i l l y  Coniferous forest  Nulki Driftwood  Loam  n  Pinchi  Clay  n  Barret  Loam  Vanderhoof  Grey Wooded  n  n  n  n  Vanderhoof  nr. Eaglesham Gently r o l l i n g to r o l l i n g Alta.  Poplar Poplar and conifers  Undulating  Alberta Grey-* Wooded  Clay Loam  ti  Fort St.James  Clay  ti  Fort.St.James Undulating to hilly  Doughty  n  n  nr. Smithers  Telkwa  it  Alberta Transition  n  Lakelse  n  Black-Grey Transition n P a c i f i c Coast  n  ooniferous forest  Telkwa  R o l l i n g to h i l l y  Grasses,popl a r & conifers  nr. Codessa Alta.  Undulating  Poplar and grasses  Terrace,B.C.  Undulating  Conifers and Bracken. 1  ** S o i l s not supplied with association names.  (8) TABLE I I Zone  PROFILE DESCRIPTIONS OF SOILS UNDER STUDY Association  Horizon  Dawson  A  n  AjUpper  Depth  Description  0-2"  B l a c k i s h , highly fibrous, tough layer formed from grass roots.  2"-7"  Black granular, f r i a b l e clay loam.  0-1"  Dark brown p a r t i a l l y decomposed remains of leaves, grasses & herbs.  AjLower l " - 6 "  Shallow Black Pinehi  Driftwood  Dark grey to almost black clay, upper two inches granular i n structure. Lower three inches dark grey granular with tendency towards platiness. The whole i s often so underwoven with grass roots that compact sod i s formed.  0-2"  BlaCk f i n e l y granular clay with an extremely tough mat of grass roots.  Al  2 - 5"  Dark grey to black highly granular clay.  Ao  0-2  P a r t i a l l y decomposed r e mains of leaves, grasses, herbs, etc.  n  <  M  Dark brown t o black, granu l a r loam, numerous grass roots and small stones present. Barret  GreyWooded  AQ  l"-2»  Dark brown p a r t i a l l y decomposed remains of masses and coniferous forest debris.  Al  2"-4  Brown f r i a b l e loam, moderately supplied with organic matter. Weak granular structure, numerous roots and stones  w  (9) TABLE II Zone  (continued) Association  Horizon  Depth  Description  Vanderhoof  A.  2"  Raw undecomposed mass of needles & twigs. The whole i s extremely f i b r o u s and contains many roots.  An  0-2"  Dark grey to brown grey clay containing considerable mere-decomposed organic material mixed with the mineral s o i l . S t r u c t ure i s granular with a s l i g h t i n d i c a t i o n of platiness i n the lower part of the horizon.  AQ  0-2"  P a r t i a l l y decomposed debris from poplar and grasses.  2"  Highly granular c l a y loam, black to grey brown.  2"  P a r t i a l l y decomposed remains of poplar leaves, grasses and coniferous tree debris.  0-2*  Dark grey to brown f i n e granular d a y .  -  Variable depth of accumulated remains of p a r t i a l l y decomposed needles, twigs and mosses.  0-2"  Grey c l a y with brownish colouring, p l a t y structure with small amount of granulation.  Grey Wooded  Alberta Grey Wooded  Fort St. James  Doughty  Ao  AQ  A^  *•  (10) TABLE I I Zone  (continued) Assooiation Horizon Depth 0-i"  Telkwa  Blaok Grey Transit* ion  Al  Alberta Transition  A  £ -4 U  Black, rooty and fibrous p a r t i a l l y decomposed remains of acornes and poplar debris. W  Lakelse  A,  A  Dark brown to black, f r i a b l e granular c l a y . This horizon varies up to 8" i n depth.  Decomposed remains of acornes and poplar leaves.  r  Ai Pacific Coast  Description  Black, granular, clay loam. 0-2"  n  ^jc Horizons not analysed i n t h i s  A dark brown fibrous mat of organic a c c u l u l a t i o n consisting of mosses, bracken and coniferous debris. Nil  study.  (11) Experimental The previously described s o i l s were analysed following i n general the method outlined by Shewan (1938).  A f t e r a number of preliminary determinations,  a number of minor changes i n the teohnique were introduced to give increased accuracy and  convenience.  These changes are as follows: (a) T h e ^ l i p i d ^ f r a c t i o n was determined by extracting the s o i l i n a Soxhlet with 50:50 alcohol-benzene f o r 48 hours instead of extracting with both ether and alcohol. Preliminary work showed that t h i s treatment  simplified  the technique without a l t e r i n g the produots removed. The extracted " l i p i d s " a f t e r removal of the solvent was dried over ^anhydrous calcium chloride to constant weight since Salisbury and De Long (1940) have reported the presence of a product which i s v o l a t i l e at 1 0 5 ° C (b) After each extraction process, with exceptions i n determination of l i g n i n t h e t o t a l residue was used f o r }  the next operation instead of taking a weighed portion of the previously extracted residues. (c) Determination,of reducing sugars was carried out by the procedure of ©tilfg,Peterson and Fred 41926) (d) Amide nitrogen was determined by d i s t i l l i n g aliquots of the 2% hydrochloric acid extract with sodium hydroxide.  (12)  (e) L i g n i n was  determined by the method of  R i t t e r et a l (19J2) f o r reasons explained i n Part B. Page 28 • The method f i n a l l y adopted f o r the analysis of the 19 s o i l s i s given as follows i n d e t a i l : a l l samples was  Carbon i n  determined by wet combustion and  nitrogen  by the standard Kjeldahl procedure. Twenty grams of s o i l from the AQ horizons, 40 grams from the A i horizons, ground to pass 40 mesh, were extracted for 48 hours i n a Soxhlet. apparatus with 50:50 alcohol-benzene.  The material soluble i n  alcohol-benzene a f t e r removal of tne solvent  was  dried over calcium chloride ~ to constant weight i n a desiccator and reported as " l i p i d ? . The residue was transferred to a l i t r e florence f l a s k refluxed with 200 o.c. of water f o r 4 hours and f i l t e r e d by suction i n a Bu&hner. The f i l t r a t e on cooling was made up to 500 Total nitrogen was  determined a f t e r  concentration  of one aliquot by the Kjeldahl method. portion of the extract was  o.c.  Another  concentrated and evaporated  down to dryness on\ a steam bath, dried i n the oven f o r 1/2 hour and weighed, then ashed and weighed again. The t o t a l ash free organic matter and t o t a l water soluble nitrogen was sample.  calculated for the whole  (13)  The residue from the Buchner funnel was transferred to the b o i l i n g f l a s k and 300 o.c. of 2% hydroohlorio acid added.  This mixture was boiled under r e f l u x  f o r 5 hours.  After cooling the f i l t r a t e was made up  to a known volume*  25 c.c. of t h i s solution was  withdrawn and neutralized with 3% sodium hydroxide to the bromg thymol blue end point.  The precipitated  iron and aluminum hydroxides were f i l t e r e d o f f and the solution made up to 50 c.c.  Reducing sugars were det-  ermined on neutral iron and aluminum free extracts by the method of S t i l e s et a l (1928).  The weight  of reducing sugar calculated as glucose i s reported as "hemioellulose'V  Amide nitrogen was determined by  d i s t i l l i n g another aliquot with sodium hydroxide.  Total  nitrogen was determined on a t h i r d aliquot of the HCL extract. The residue a f t e r Mcl hydrolysis was dried i n the oven and weighed.  Ten grams of residue from A^  horizons and 3 grams from AQ horizons were transferred to a 100 c.c. glass stoppered conical f l a s k , 25 c.c. of 72%H2SK>4 were added and allowed to stand f o r 2 hours at 20°0. as recommended by K i t t e r et a l (1932).  The  contents were transferred to a l i t r e f l a s k and d i l u t e d to make 3% H2SO4. under r e f l u x .  The solution was boiled f o r 5 hours  On oooling and f i l t e r i n g reducing  sugars were determined as before and reported  as c e l l u l o s e  (14) on the basis of the whole sample. The residue from the f i l t e r was transferred to ta?ed  ;  dish and weighed and carbon (wet combustion)  nitrogen (Kjeldahl) were determined. Using Waksman* (1930) formula the " l i g n i n - p r o t e i n " complexes were calculated f o r the o r i g i n a l sample*  (15.) DISCUSSION OF THE VARIOUS FRACTIONS 1.  Alcohol-benzene soluble f r a c t i o n * Treatment of s o i l with alcohol-benzene removes the f a t s , waxes and resinous  2.  mixture substances.  Water soluble f r a c t i o n . The nature of organic oompounds dissolved by hot water i a quite i n d e f i n i t e .  Shorey (1930) points  out that such material may be  predominately  organo-aluminum compounds from the c o l l o i d a l complex.  He further points out that the quantity of  water soluble materials increases a f t e r treatment of the s o i l with solvents. 3«  Hemicellulose. I t i s recognized that no single determination can give a complete estimation of hemicellulose present i n organic matter.  The hydrolysis method  involving the use of 2% hydrochloric acid i s used i n t h i s work, i t being expressly understood that t h i s determines those hemicellous whose sugar produots on hydrolysis are not destroyed by the acid treatment.  How t a r such a treatment i s a true  estimate of the hemicellulose present i s impossible to say.  (16) 4.  Cellulose, Where both c e l l u l o s e and l i g n i n are being determined  on the same sample conditions favourable f o r both determinations are not w e l l defined.  The hydrolysis  method according to Shewan (1938) gives lower r e s u l t s than the Cross and Bevan Method (A.O.A.C. 1945) 5.  Lignin-protein complex. The separation o f c e l l u l o s e and l i g n i n through  the use of 72% sulphuric acid probably strongly a f f e c t s the l i g n i n . Xylose  Norman and Jenkins (1934) point out that  cjind fructose w i l l polymerize into insoluble  compounds i n the presence of concentrated sulphuric acid thereby increasing the figure f o r l i g n i n .  Direct methods  for determination of c e l l u l o s e and l i g n i n i n plants and composts are suggested by .Norman and Jenkins 11933.) Since gashes are involved, the methods do not seem p r a c t i c a l f o r routine laboratory analysis.  A complete review of  the methods of determination of hemicelluloses, c e l l u l o s e s and l i g n i n s i s given by Norman U937).  (17) RESULTS AND DISCUSSION OF RESULTS The a n a l y t i c a l r e s u l t s f o r percentages of carbon and nitrogen and f o r the carbon-nitrogen r a t i o of the s o i l s examined are given i n Table I I I .  Examination  of t h i s data reveals that the percentage carbon i n the AQ horizons of the ^rey Wooded and P a c i f i c Coast s o i l s i s higher than the percentage carbon i n the A  0  horizons of the Shallow Black and Transition s o i l s .  On  the other hand, the percentages of organic carbon i n the horizons of the Forest s o i l s i s lower than the percentage carbon i n the A^ of the Shallow Black and Transition s o i l s .  I t appears that mineralization of  the organic matter has been more complete i n the grassland soils.  This conclusion i s supported by data that has shown  the surface layers of p r a i r i e s o i l s to have a higher microbiological a c t i v i t y than the surface layers of Forest s o i l s . (Vandecaveye and Katznelson 1940-Cook,194$). .Examination of Table I I I demonstrates the well recognized differences between the C:N of forest and grassland soils.  The s o i l s of the shallow black zone have a narrow  C:N ranging between 6.05 and 29.7  f  s o i l s of the t r a n s i t i o n  zone also have a narrow C:N ranging between 8.3 and 24.6, and s o i l s of the Wooded and P a c i f i c Coast zones have a wide C:N ranging between 17.6 and 58.  (18) TABLE I I I Zone  PERCENTAGE CARBON, NITROGEN AND C:N of the SOILS UNDER STUDY Association  Horizon  Depth  % Organic %Total C N  Dawson  Al  2-7"  15.6  1.01  15.4  Shal low  Nulki  AjUpper  0-1"  12.5  0.777  16.1  Blac k  Nulki  A^Lower  1-6"  15.6  0.980  15.9  Pinchl  A  0-2"  25.0  0.842  29.7  Pinchi  Al  2-5"  11.3  0.977  11.6  A  l  2-5"  A  0  1-2"  Barret  A  l  2-4"  Grej  Vanderhoof  A  o  2"  Woodled  Vanderhoof  A  l  o-e»  Driftwood Barret  0  5.20 41.8 3.48  58.3 3.44  0.797  C:N  6.05  1.19  35.1  O.136  32.9  1.46  39.9  0.156  22.0  I.036  20.4  Alberta, GreyWooded  A  0  0-2"  21.6  Alberta, Brey Wooded Port St.James Doughty  Al  2-4"  4.15  0.233  17.8  A  l  0-2"  6.15  0.349  17.6  A  o  1.21  38.6  2.24  8.3  0.463  17.4  1.24  24.6  0.477  10.5  1.04  58.1  Telkwa  A  Telkwa  Al  Trar isitioE Alberta Transition Alberta Transition  0  variable i 41.6  0-|2 i-4»  A  o  2"  A  l  2-4"  A^  0-2"  18.8 8.10 30.4 5.00  Pacific Coast  [t'akelse-'  58.2  (19) The relationship of vegetative types to C:N i s i l l u s t r a t e d by these examples:  Driftwood under a gross  vegetation with few poplar and no conifers has a 0:N of 6, Fort S t . James under poplar with some grass has a C:N of 17.6 and Lakelse under coniferous forest only has a 0:N of 5 8 . 1 . The r e s u l t s of the proximate analysis f o r the 19 s o i l s studies are recorded i n Table IV.  The figures f o r each  f r a c t i o n are averaged on the zonal basis f o r both the AQ and A± horizons of each association i n order t o make comparison somewhat easier.  I t i s strongly emphasized  that the values i n terms of " l i p i d s " , "hemicellulose", " c e l l ulose", " l i g n i n " and "protein" have significance only as accorded them i n other studies of t h i s nature.  The use of  these terms does not imply either that the fractions so designated consist s o l e l y of the chemical substances of these classes or that the recovery of chemical compounds of these classes has been quantitative. Examination of Table IV shows differences i n the constituents recovered from s o i l associations within a zone and from the horizons within the s o i l associations. Although none of these differences are s t r i k i n g at f i r s t glance they may be s i g n i f i c a n t .  The " l i p i d " ' f r a c t i o n i s  highest i n the wooded s o i l s as might be expected considering the amount of resins i n coniferous debris.  The appearance  of the alcohol-benzene soluble materials from the various  TABLE VT  Zone  PROXIMATE ANALYSIS OF SOILS UNDER STUDY  Association  Horizo  4  Dawson  Percentage Based on Organic Matter (Oxl»724) Nitrogen Organic L i p i d Water Hemicell- C e l l u - L l g n i n Complex Matter Soluble ulose lose (Nx6.25)  Recovery  2£.9  1*67  2.85  15.8  7.034  37.9  12.4  77.7  12.7  4.70  33.1  20.6  81.2  2.86  48.9  17.7  82.9  Nulki  AjUpper  21,6  4.32  3.80  Shallow  Nulki  AjLower  26.9  2.32  4.12  Black  Pinchi  42.8  3.21  3.23  21.0  13.1  36.2  Pinchi  19.5  2.97  3.78  17.7  11.8  39.4  16.8  92.5  8.9  3.90  2.56  28.9  20.7  30.8  10.3  97.1  3.76  5.51  16.8  34.6  14.5  2.76  3.32  17.1  39.2  14.3  Driftwood  Average  Ao  it  6.13  8.90 10.5  8.41  87.05  91.6  Barret  Ao  71.8 -  5.72  4.20  26.2  6.98  42.7  Barret  -A,  6.0 -  6.34  8.50  10.4  Trace  38.6  14.5  78.3  Grey  Vanderhoof  A.  4.90  3.22  10.1  3.28  43.2  13.8  78.5  Wooded  Vanderhoof  A-,  2.36  8.00  8.29  29.5  23.5  79.6  „  3.23  3.44  11.4  7.14  53.4  7.13^  2.69  6.20  10.7  10.6 ^  2.52  3.92  100,0 5.92*  8.021  5.77  Alberta Grey Wooded  Ao  n Fort St.James  71.9  Uoughty  Average  37.1  A,  n  6.15  10.7 1.71  9.41  48.1  11.1  82.6  52.9  13.5  8O.7  103.0  7.23  4.28  18.3  5.027  60.5  7.i4  5.34  3.78  16.5  5.60  50.0  9.09  3.67  6.65  5.17  42.2  15.6  8.80  87.8  Grey Black Telkwa  32,2 '  1.72  6.17  16.8  4.00  38.3  11.3  48.3  Transition  14.0 /  1.40  3.32  15.7  1.041  43.3  12.6  77.4  $2.3  2.94  2.84  20.01  2.28  51.1  7.50  86.5  3.08  6.50  17.6  5.34  50.8  7.15  90.4  2.33  4.50  18.4  3.14  44.7  9.40  2.24  5.41  16.6  3.19  47.0  9.87  7.00  ?1.H  Alberta Transition A,  8.62  Average A-, Pacific Coast  Lakelse  100.0  1.01  8.19  27.?  80.0  (21) s o i l zones shows some i n t e r e s t i n g differences.  These  extracted materials were a reddish brown and/acid to litmus i n the forest soils,and a canary yellow and neutral to litmus i n the Shallow Black and T r a n s i t i o n soils.  The s i g n i f i c a n c e of these observations i s not  f u l l y appreciated at the present time.  Perhaps a f t e r  further i n v e s t i g a t i o n a l work organic matter may characterized by the chemical nature of the  be  "lipids".  Water soluble constituents are higher i n the A-^ horizons of a l l s o i l s regardless of zone, but the i n d e f i n i t e nature of the substances involved reduces the significance of t h i s observation.  Attention i s drawn to  the extremely low water soluble oontent of Lakelse  A  Q #  This s o i l i s formed under an annual p r e c i p i t a t i o n of 70 inches.  In a proximate analysis of Western Washington  p r a i r i e s o i l s , (Fower and Wheeting 1941)  found a  c o r r e l a t i o n between r a i n f a l l and water soluble c o n s t i t uents. There i s no apparent differences between the "hemicellulose" and " c e l l u l o s e " contents within the 4 s o i l zones.  Results of both these fra'ctions are, i n  f a c t , very inconsistent.  However, the decrease i n both  "hemicellulose" and " c e l l u l o s e " from the AQ to the A^ horizon of a l l s o i l s regardless of zone seems to be significant.. I t w i l l be noted that the c e l l u l o s e oontent  (22) i n most cases i s lower than the hemicellulose.  Cellulose  being one of the main energy sources f o r micro-organisms, i s broken down rapidly during decomposition of plant remains.  The hemicelluloses, on the other hand, are made  up c h i e f l y of pentosans, hexosans andpolyuronldes that are quite resistent to decomposition (Waksman and Diehm 1931a 1931b).Polyuronides* increase on decomposition of plant remains because of extensive synthesis by micro-organisms (Norman 1941). For these reasons, the "hemicelluloses" are usually higher than " c e l l u l o s e s " • And according to (Waksman et a l 1928) comparison of the decomposed l i t t e r with a variety of f r e s h plant materials shows a marked accumulation of "hemicelluloses". The " l i g n i n " content on the average, i s higher i n the Grey Wooded s o i l s .  Vandecaveye and Katznelson (1940)  found t h i s tendency i n an examination of Washington zonal s o i l s by the proximate analysis.  The  "lignin"  content i n the AQ horizons of the Shallow Black s o i l s i s somewhat lower than the " l i g n i n " i n the corresponding A-j_ horizon.  In the wooded s o i l s the s i t u a t i o n i s the reverse.  The differences between A  Q  and A^ i n Shallow Black s o i l s may  due to increased decomposition as was pointed out previously. Results f o r nitrogenous complexes are rather inconsistent but a general trend f o r a higher value i n the A± horizons i s demonstrated. The recovery of constituents varied between 77% and 102% of the t o t a l organic matter with a mean recovery of 85%.  be  (23), This recovery agrees c l o s e l y with those reported by Gross (1947) and DeLong and Salisbury (1940) but i s r e l a t i v e l y low.  This may be due to solution of " l i g n i n " i n the  acids used f o r hydrolysing the "hemicellulose" and  "cell-  ulose". Waksman and Hutchings (1935) have previously reported such a l o s s i n the f r a c t i o n a t i o n of organic matter of podsol s o i l s .  They attempt to make a correction  f o r the amount of " l i g n i n " dissolved by analysing the acid f i l t r a t e s f o r t o t a l carbon, subtracting the carbon equivalents of the amounts of "hemicellulose", " c e l l u l o s e " and hydrolysed "protein" found present i n the hydrolyzates, and c a l c u l a t i n g the remainder of carbon to " l i g n i n " . Even then, the assumption that a l l of the r e s i d u a l carbon i s l i g n i n derived i s scarcely j u s t i f i a b l e .  The f a c t o r 1.724  2.20  i s for organic matter i s a r b i t r a r y and may vary between and 1.79  x C  x c f o r high carbon s o i l s i s shown by Lunt (1936).  In table V the nitrogen d i s t r i b u t i o n of the various s o i l s are expressed  as per cent of the t o t a l nitrogen  i n the whole s o i l .  Nitrogen soluble i n 72% sulphuric a c i d  was not determined because of the low recovery on several extracts taken at random.  This nitrogen f r a c t i o n i s  included i n the f r a c t i o n , "nitrogen unaccounted f o r . " r e s u l t s f o r water soluble nitrogen i n Barret A  Q  and A l b e r t a  Grey Wooded s o i l A^^ are rather s u r p r i s i n g since 24.9% 2017%  The  of the t o t a l nitrogen present i s water soluble.  and No  explanation can be offered f o r t h i s f a c t . "Protein" nitrogen  (24)  TABLE 7  NITROGEN DISTRIBUTION IN THE SOILS STUDIED (Expressed as % Total Nitrogen)  IT  Association  Horizon Water Protein Nitrogen Soluble' Hcl Non .'Soluble Nitrogen UnaccounN. ted f o r Amide Amide N. JL  Dawson  Al  6.30  14.7  15.7  64.4  -1.1  Nulki  AjUpper 9.80  25.2  10.6  46.2  7.2  Shallow  Nulki  AiLowex|13.1  8.52 17.1  58.3  14.8  Black  Pinchi  Zone  o  10.3  21.1  23.3  47.5  -2.3  Pinchi  Al  10.0  9.7  21.4  51.5  7.4  Driftwood  Al  a  8.15 48.0  7.6  35.8  43.5  -5.5  14.2  53.6  10.7  8.53 32.8  45.2  2.8  12.01 15.5  64.5  2.3  17.3  14.5  34.0  8.9  3.10  1.87 25.2  70.1  -0.27  8.25  8.33 30.4  53.7  -0.68  15.4  57.6  -0.35  8.16| 13.5  67.4  0.64  Barret  A  0  Barret  A  l  8.55  17.7  A  0  4.80  16.7  Vanderhoof Grey  Vanderhoof  Wooded  Alfrerta Grey Wooded  Al  A  o  A  l  A  Telkwa  A  10.7  5.71 20.3  Fort St .James Doughty  24.9  0  10.3  Black-Grejf Telkwa Transitioi  Alberta Transition  A Al  5.25 10.3  22.1  Pacific Coast I  Lakelse  12.5  12.1  9.50 63.4  2.5  (2$) or nitrogen insoluble i n 72% sulphuric a c i d accounts f o r 34-70% of the t o t a l nitrogen of the s o i l s examined. Although there are no apparent differences between zones, as i n " l i g n i n " (Table I Y ) there i s a marked tendency f o r accumulation of protein nitrogen i n the A-L horizons. CONCLUSIONS Although the r e s u l t s of the proximate analysis do not show s t r i k i n g differences between the zonal s o i l s studied some i n t e r e s t i n g r e s u l t s have been demonstrated.  From a study of percentage organic  matter i t appears that the s o i l s of the Shallow* Black and Transition zones are more  completely  mineralized than the s o i l s of the Grey Wooded and P a c i f i c Coast zones.  In demonstrating increased mineralization  and hence increased intermixing of mineral and organic f r a c t i o n s , the organic matter of the grassland s o i l s may be c l a s s i f i e d as a mull type while that of the Wooded s o i l may be c l a s s i f i e d as a mor type. There was no s i g n i f i c a n t differences i n "hemicellulose" and " c e l l u l o s e " between the s o i l s of the 4 zonal groups, but the " l i g n i n " content of the Grey Wooded s o i l s i s higher than that i n the Grassland  soils.  A comparison of differences between the AQ and Ai_ horizons of a l l s o i l s indicate rather c l e a r l y :  decreased  "hemicellulose and " c e l l u l o s e " and increased " l i g n i n " and  (26)  nitrogen complex i n passing from the AQ to the A^ horizon. Fractionation of nitrogenous compounds gave r e s u l t s too inconsistent to be s i g n i f i c a n t . The proximate analysis of the Driftwood s o i l suggests that t h i s s o i l should not be c l a s s i f i e d as Shallow Black but should perhaps be included i n the Black-Grey Transition group. The value of the proximate analysis f o r the study herein described i s questionable.  There i s need f o r the  adoption of methods l e s s empirical than those used i n the proximate  analysis.  (27) PART B.  STUDY OF LIGNIN IN ORGANIC MATTER OF BRITISH COLUMBIA SOILS. Review  of L i t e r a t u r e  L i g n i n i s found mainly i n the secondary wall and pargly i n the middle lamella of the plant.  There has been  much speculation as to the o r i g i n of l i g n i n and the mechanism of l i g n i f i c a t i o n but the scope of t h i s work does not provide f o r a d e t a i l e d discussion of these t h e o r i e s . However i t may be mentioned, that two of the recent theori e s on l i g n i n formation are given i n d e t a i l by Freudenberg (1939) and Hibbert  (1942).  Methods of Determination and I s o l a t i o n of L i g n i n . Since l i g n i n has a very r e s t r i c t e d s o l u b i l i t y the methods adopted for i t s i s o l a t i o n are more or l e s s d r a s t i c , and may bring about changes, the nature of which, are not known.  Through the a c t i o n of concentrated acids i n the  cold, c e l l u l o s e , hemicellulose, and other polysacchorides pass into solution.  The l i g n i n remains behind and i s  f i l t e r e d o f f , dried at 105°C and weighed.  A correction  f o r ash and protein i s u s u a l l y applied to the weighed product.  Varying strengths of sulphuric acid from 65%  to 80% have been used from time to time.  But 72% sulphuric  acid has been found to give most s a t i s f a c t o r y r e s u l t s and i s recommended by the A.O.A.C. (1945).  The conditions under  which the determination i s c a r r i e d out has been the subject of much research and those set down by H i t t e r et a l (1932) are generally followed.  They stress 3 important points i n  (28) making the l i g n i n determination: contact time of 2 hours, constant temperature of 20°C and f i n a l hydrolysis of s o l uble constituents i n 37» sulphurio acid f o r 4 hours. Norman and Jenkins (1934) emphasize the necessity f o r s t r i c t adherence to these conditions since,as they point out, c e r t a i n sugars, p a r t i c u l a r l y xylose and fructose and sucrose by reason of i t s fructose content give an insoluble residue on standing i n 72% sulphuric a c i d ,  i'he  disturbance caused by these sugars increases i f the time of contact with the acid i s prolonged but i s not serious i f l i m i t e d to 2 hours at 20°C.  The nature of the condensat-  ion products i s discussed at length by the authors. Another method i n which a l l other constituents are dissolved out with 42-43°% fuming hydrochloric acid has been described by W i l l s t a t t e r and Kaeb (1922) and the product so obtained from t h i s treatment i s c a l l e d "Willstatter" lignin.  Since the action^fuming hydrochloric  acid i s about the same as concentrated sulphuric acid no p a r t i c u l a r advantage i s gained tnrougji i t s use. A l i g n i n residue c a l l e d "Freudenberg l i g n i n " has been obtained through the d i s s o l v i n g of the c e l l u l o s e and hemicellulose of l i g n i f i e d tissue i n cuprammonium s o l u t i o n . As the name suggests the metnod was  devised by Freudenberg  et a l (1928). A number of methods based on the solution of the l i g n i n by solvents and the weight of the dissolved portion  (29) calculated as l i g n i n have been described.  The  commercial  preparation of c e l l u l o s e from wood depends upon the f a c t that on heating the wood with sulphites d e l i g n i f i c a t i o n occurs through the formation of soluble acids.  ligno-sulphonic  The method of l i g n i n determination based on the  sulphurous acid reaction i s not generally used since some of the c e l l u l o s i c compounds are dissolved.  Mild a l k a l i n e  conditions have also been used for the extraction of l i g n i n . In such cases, the material i s treated with a l c o h o l i c sodium hydroxide under pressure and the dissolved l i g n i n i s precipitated by n e u t r a l i z a t i o n .  This method i s extremely  e f f e c t i v e i n removal of l i g n i n f o r obtaining a l i g n i n free c e l l u l o s i c residue, but f o r the determination of l i g n i n degradation of polyuronides adds to the error and f o r t h i s reason i s not recommended ( P h i l l i p s 1927). L i g n i n i n S o i l Organic Matter. The occurrence of l i g n i n i n organic matter can be demonstrated through the application of the well known q u a l i t a t i v e t e s t s f o r native l i g n i n .  Shorey and Lathrop  (1911) show that me/tfctasyl i s present i n organic matter. Some of the microtests f o r native l i g n i n such as the phlorglucinal test and r e s o r c i n a l test have been successfully applied to the l i g n i n s i n the s o i l (Shorey 1930).  The  presence of a complex insoluble i n sulphuric acid, has  already  been shown i n part A of t h i s paper and Norman and Moody(1940) using a number of d e l i g n i f i c a t i o n procedures, have demonstrated  (30) the presence of l i g n i n i n the organic f r a c t i o n horizons A Q and A Biological  1  of s o i l  #  Decomposition of L i g n i n  Many c o n f l i c t i n g  and contradictory statements have been  made i n regard to the a v a i l a b i l i t y o f l i g n i n to microbial attack and the general consensus of opinion i s that isolated  l i g n i n at least i s unavailable. (Norman 1937.PP.177).  But since a l l methods of l i g n i n i s o l a t i o n involve the use of drastic reagents the U n a v a i l a b i l i t y of i s o l a t e d  lignin  cannot be taken as a c r i t e r i o n for ( i n a v a i l a b i l i t y of l i g n i n Infeitu* > Certain s p e c i f i c fungi are capable of decomposing l i g n i n i n the plant, as, f o r example wood destroying fungi (Norman 1937* pp.179, the edible mushroom, P s a l l i a t a camnestris Waksman and Nissen (1931) and species of Coprinus,Waksman (1931). Boruff and Buswell (1934) show that "Klason" added to an a c t i v e l y  lignin  fermenting glucose media stops the  gas production instantly  and further additions of glucose  w i l l not revive the process.  Similarly  a l k a l i l i g n i n has a  r e s t r i c t i v e action on microorganisms as was demonstrated by Levine et a l (1933).  Phenol l i g n i n has been shown,  s u r p r i s i n g l y enough, to be decomposed by a number of -bacteria and fungi. (Waksman and Hutchings 1936).  Bartlett  and Norman (1939) show a decrease i n methoxyl content as decomposition proceeds i n compost heaps and a t t r i b u t e t h i s fact to microorganisms. Synthesis of l i g n i n by Microorganisms. The presenoe of l i g n i n - l i k e complexes i n some s o i l fungi  (3D was  demonstrated f o r the f i r s t time by Thorn and P h i l l i p s  (1932) and l a t e r the a b i l i t y of fungi to these complexes was Cladisporium  synthesize  studied by Pinck et a l ( l 9 4 3 ) .  and Helmlnthosporium species were shown  to be capable of synthesizing a 72% sulphuric acid insoluble complex from glucose.  This complex comprised  from 16.6-23.9% of the t o t a l dry weight of the  mat.  Other genera including A s p e r g i l l u s , Gliocladium  and  A l t e r n a r i a also synthesized l i g n i n i n l e s s e r amounts. The l i g n i n synthesized by fungi d i f f e r e d chemically from native l i g n i n i n that i t contained l e s s methoxyl. P r a c t i c a l Significance of L i g n i n i n S o i l The base exchange capacity of organic matter layers was  studied by M i t c h e l l (1932) who  found that 40% -  70%  of the t o t a l exchange capacity of organic s o i l s could be attributed to the organic f r a c t i o n and i n t h i s l i g n i n plays a major r o l e .  M i l l e r et a l (1936), too,  concluded that the exchange capacity of organic  soils  i s s i g n i f i c a n t l y correlated with l i g n i n content and that the t o t a l exchange capacity increased with decomposition.  McGeorge (1934) v e r i f i e d t h i s  observation  and stressed the low t o t a l exchange capacity of fresh plant materials. Waksman and Hutohings(1935) while investigating the function of l i g n i n i n the preservation of nitrogen i n s o i l s suggested that the aldehydic groups of l i g n i n combine  (32) chemically with the amino groups i n protein forming a l i g n o protein complex of the nature of a S c h i f f s * base. complex i s stable i n the presence of 72%  This  sulphuric acid and  contains 30%-70% of the s o i l nitrogen as has already been shown by the proximate analysis. Since organic matter i s of paramount importance i n a s o i l , and since l i g n i n or l i g n i n - l i k e complexes  comprise  30-70% of the organic f r a c t i o n i n a s o i l , and since l i g n i n i s by no means f u l l y understood there i s a r e a l need f o r further study on the chemical nature and p r a c t i c a l s i g n i f icance of l i g n i n i n organic matter. Recent Advances i n L i g n i n Chemistry. Researches devoted to a study of the composition of plants during recent years have disclosed that aainarked difference exists between the l i g n i n s Isolated from gymnosperms or softwoods and those isolated from angiosperms or hardwoods. Hibbert and co-workers (1939) f o r instance have shown that i n the l i g n i n from angiosperms there are present both the 4 hydroxy-3-methoxyphenyl  and the 4  hydroxy-3-$-dimethoxyphenyl  n u c l e i ; whereas i n the l i g n i n from gymnosperms only the 4-hydroxy-3-methoxyphenyl  nucleus i s present.  Thus  employing an ethanolysis procedure attgiosperm l i g n i n s yielded a mixture of compounds I , I I , I I I , 17 and V while l i g n i n from gymnosperms obtained i n s i m i l a r manner gives i n addition the corresponding syringyl analogs VI, VTI, VIII and IX. The  oombined y i e l d s of pure products from angiosperms and  gymnosperms amounted to 9.7% and 3% respectively.  (33)  /  \  ? V  u  I -3-methoxyphenyl)-l-propanone  2 ethoxy - 1 - (4 hydroxy C  H  -^  Ho<  o ) - C f - 1C/ - C M H  3  II 1 ethoxy - 1 - (4 hydroxy - 3 - methoxyphenyl)-2-propanone CH < 3  o  ©  «  i/  C — C — CH  3  III l-(4-hydroxy-3-methoxyphenyl) 1-2 propandione CH Q  O  3  l - ( 3 hydroxy-4-methoxyphenyl) c  «3<\  V Vanillin  2-propanone  (34)  O II  H I  71 2-ethoxy - l(4-nydroxy -3,j>,-dimethonypnenyl) 1-propanone, /  y—~\  t ?  VII 1(4 hydroxy-3,5-dtmethoxyph.enyl) 1,2, propanedione.  VIII 1 (4 hydroxy-3.3 dimethoxyphenyl) 2 propanone. CH C{ 3  CH a 3  Syringaldehyde.  ix.  Freudenberg et a l (1940) employed a nitro-benzene oxidation technique that gave from spruce l i g n i n v a n i l l i n V only i n 20% y i e l d .  Maple l i g n i n gave a mixture of v a n i l l i n V  and syringaldehyde IX i n r a t i o 1:3 and i n y i e l d s as high as 33% of the i n i t i a l Klason  lignin.  With the foregoing data i n mind i t was considered worth while to Investigate the p o s s i b i l i t y of applying one of these l i g n i n techniques to s o i l organic matter.  Should such  a procedure be applicable i t might perhaps enable one to determine the character of vegetation from which the organic horizons of some of the degraded s o i l s have been derived and so provide another basis f o r d i f f e r e n t i a t i o n (  of s o i l s .  L i g n i n isolated.by means of 72% sulphuric a c i d . ) EXPERIMENTAL The Freudenberg oxidation technique as described  by Creighton et a l (1944) was used i n a study of the following s o i l organic residues and plant materials; Description of Samples Soils. Dawson  A^  - See description page 8 •  Vanderhoof  AQ  -  "  Daughty  A  -  •  Q  Forest L i t t e r  "  M  »  *  Douglas F i r S i t k a Spruce Rye Straw  9  . .  - Decomposed needles, twigs etc. from U.B.C. Forest f l o o r .  Woods and Straw  9  (36) Procedure and Description of Procedure The samples were ground i n a Wiley mill.pass a 60 mesh sieve.  The a i r dry meal was extracted i n  a Soxhlet f o r 48 hours with a 50-50 alcohol-benzene mixture, 12 hours with ethanol and 6 hours with hot water.  The extracted material was dried f i r s t by  suction and then by low heat.  Duplicate two gram  samples of the extracted a i r dry meal were used f o r determination of moisture.  Twenty grams of extracted  meal, 12 ml. of nitrobenzene and 400 ml. of 8% sodium hydroxide were placed i n a steel bomb (Figure 1) and heated to l65°C. i n an o i l bath.  The bomb was then  transferred to the shaker and oven (FigureIII) where the bomb temperature was maintained at l60°C. f o r 3 hours with violent shaking (300 strokes per minute). A f t e r cooling, the contents were f i l t e r e d at the pump and the residue washed with 8% sodium hydroxide and f i n a l l y with water.  The washings and f i l t r a t e were  a c i d i f i e d with sulphuric acid to ph 3 and the r e s u l t i n g mixture continuously extracted f o r 48 hours with benzene. The benzene extract was shaken with 20% sodium b i s u l p h i t e for | hour.  The b i s u l p h i t e extract was a c i d i f i e d and  sulphur dioxide removed under reduced pressure at room temperature u n t i l no odour of the gas could be detected and then f i l t e r e d and made up t o 500 ml.  F i f t y ml. of  the bisulphite solution were taken f o r the determination of t o t a l aldehydes by adding 10 grams of sodium acetate  FIG- I  STEEL BOMB  c  (39) and a solution .23 grams of m nitrobenzoyl hydrozide i n 25 ml. of water. at 60°C.  The hydrozones form almost immediately  The precipitate was allowed to stand at 60°0  for h hour and at room temperature over-night. The hydrozones were f i l t e r e d , washed with d i s t i l l e d water and dried over anhydrous calcium chloride and weighed. The remainder of the b i s u l p h i t e solution was extracted f o r 48 hours with benzene and the solvent removed.  The resulting o i l s were dried f o r 15 minutes  i n vacuum and stored i n a desiccator. V a n i l l i n and syringaldehyde were separated by adding a weighed amount of o i l s (about .4 grams) to a sublimation tube (Figure  II) f i t t e d with a cold f i n g e r .  Vaouum  equivalent to about 1.5 mm. was applied and the sublimation temperature kept at 6 l ° 0 . by means of a chloroform bath f o r 5 hours.  The v a n i l l i n sublimate was removed  by means of dry ether and the solvent removed. The v a n i l l i n was weighed and tested f o r melting point depression.  V a n i l l i n i n the o i l s was then calculated and syring-  aldehyde determined by difference. Considerable preliminary work on the procedure was necessary before the data of Creighton and co-workers for rye straw and spruce wood could be duplicated. Temperature of Bomb At the outset about 1 § hours was required t o heat the bomb to a temperature of l60°C. i n the oven but as  (40) poor y i e l d s of aldehydes from rye straw were obtained (Table 71) another method of heating had to be devised. In t h i s method the sealed bomb was immersed i n an o i l bath at about 150°C.  The temperature of the bath was  then raised to l63°C. and the hot bomb quickly transferred to the preheated oven.  This pre-treatment s u b s t a n t i a l l y  reduced the time required f o r heating t o the desired temperature and at the same time greatly increased the aldehyde y i e l d as indicated i n Table VI.  Extreme care  must be exercised owing to the danger of explosion due to the exothermic reaction of nitrobenzene as an oxidizing agent. TABLE VI Expt.  OXIDATION OF RYE STRAW.  Heat Treatment  Speed of Shaking Total aldehydes ^Strokes per min. gm./20 gm.meal  1  Heating bomb i n oven  300  3.2  2  Preheating bomb In o i l  300  23.1  I t was also found necessary to maintain a constant temperature at l 6 0 ° ^ 1 ° f o r maximum y i e l d s .  Preliminary  work with Rye straw showed decreased y i e l d s where the bomb was heated by a gas oven the temperature of which varied between 155° 0. and 163° C.  (41)  FIG.  Ill  (42) Speed of Shaking Various speeds of shaking were t r i e d but a speed of 300 strokes per minute has been used f o r a l l work reported. A higher speed may be desirable but 300 strokes per minute was the maximum possible f o r the shaking apparatus (Figure I I ) used, as serious v i b r a t i o n e f f e c t s came into play beyond t h i s point. Extraction of Aldehydes. Two other extraction methods were t r i e d on the s o i l organic matter oxidation products but no aldehyde was recovered.  There were: (a) Prolonged extraction with  benzene at ph 8 as was recommended by Freudenberg (1940) (b) Extraction by refluxing with 5-20 ml. portions of triohlorethylene as recommended by Kurschner (1928). Oolorimetrio Determination of Aldehydes. Since the gravimetric determination of aldehydes i s extremely tedious and time consuming a colorimetric determination f o r V a n i l l i n using F o l i n ' s reagent (A.0.A.C.1945) was used on the bomb extracts.  Comparison of the gravimetric  and colorimetric methods and spruce wood and forest l i t t e r extracts are shown i n Table VII.  Reference to these data  shows too high a y i e l d by the colorimetric method which suggests that some compound i n the bomb extracts other than aldehydes i s reacting with F o l i n * s reagent.  In an attempt to  v e r i f y t h i s idea the colorimetric procedure described by Estes (1917) was used on the bomb extracts.  In both spruce  wood and l i t t e r a bright red colour appeared instead of the  (43)  TABLE VII-VANILLIN  BY DIFFERENT METHODS. Grams/20 grams meal V a n i l l i n as m n i t r o benzoyl hydrozone  Source  Vanillin by F o l i o s  Spruce Wood  0.938  1.54  Forest L i t t e r  Trace  O.683  c h a r a c t e r i s t i c purple.  A red colour according to Estes was  produced by v a n i l l i c , a c i d . be disoussed l a t e r .  The significance of t h i s fact w i l l  In view of these findings the colorimet-  r i c procedure appears to be of l i t t l e value f o r the determination of t o t a l aldehydes. DATA AND DISCUSSION The r e s u l t s f o r the nitrobenzene oxidation of the samples previously described are shown i n Table VIII>. Table VIII  NITROBENZENE OXIDATION OF ORGiiNIC MATTER, VJOODS, AND RYE STRAW. Based on L i g n i n L i g n i n "A Total V a n i l l i n Syringaldehyde % Aldehydes%  "Source  %  Ratio: Syrlngaldehyde to Vanillin  1  Spruce Wood  20.3  21.4  21.0  None  2  Douglas F i r Wood  28.6  10.7  10.1  None  3  Rye Straw  19.1  23.1  12.6*  10.5  1:0.83  4  Forest L i t t e r  71.6  Trace  5  Doughty A  60.1  None  6  Dawson A±  10.3  None  7  Vanderhoof A Q  43.2  None  -  -  -  Q  ^ V a n i l l i n f r a c t i o n contains p. hydroxybenzaldehyde Creighton and Hibbert (1944)  (44) I n o r d e r t o compare these r e s u l t s , d a t a on t h e n i t r o benzene o x i d a t i o n o f a number o f p l a n t s p e c i e s by C r e i g h t o n et a l (1944) i s p r e s e n t e d i n t a b l e I X .  The r e s u l t s  (Table V I I I ) f o r r y e s t r a w and spruce wood siaow a somewhat l o w o r t o t a l aldehyde y i e l d t h a n r e p o r t e d by C r e i g h t o n and co-workers b u t t h e r e c o v e r y o f v a n i l l i n and s y r i n g a l d e hyde based on t h e t o t a l aldehydes i s comparable.  F i r wood  was n o t examined by t h e s e workers b u t r e f e r e n c e t o T a b l e V T I I shows a good r e c o v e r y o f v a n i l l i n as based on t o t a l and no s y r i n g a l d e h y d e .  aldehyde,  I n t h i s r e s p e c t f i r wood has t h e  same n i t r o b e n z e n e o x i d a t i o n c h e m i s t r y as the o t h e r angiosperms examined by C r e i g h t o n . Data as p r e s e n t e d i n T a b l e V T I I i n d i c a t e t h e absence o f a l d e h y d e s except i n t r a c e amounts i n s o i l o r g a n i c m a t t e r samples, a l t h o u g h t h e same t e c h n i q u e used f o r r y e s t r a w , spruce wood and f i r wood was employed.  Further investigations  w i t h f o r e s t l i t t e r u s i n g 20 gms., 15 gms., and 10 gms. o f s o l v e n t e x t r a c t e d meal d i d not i n any case y i e l d more t h a n a t r a c e o f aldehyde. I t might be c o n c l u d e d t h e n , t h a t t h e groups i n v o l v e d i n t h e n i t r o b e n z e n e o x i d a t i o n a r e a l t e r e d i n t h e normal p r o c e s s o f o r g a n i c m a t t e r d e c o m p o s i t i o n i n s o i l t o a degree g r e a t e r than has been n o r m a l l y s u s p e c t e d .  A p a r t from t h e  p o s s i b l e change i n t h e l i g n i n i t s e l f , s e v e r a l t h e o r i e s s u s p e c t i n g t h e inadequacy o f t h e t e c h n i q u e and suggested improvements a r e advanced:  f r e e amino n i t r o g e n groups may  r e a c t w i t h t h e aldehyde and t h e r e b y b l o c k t h e f o r m a t i o n o f  W i l e t h i s t h e s i s was a t t h e t y p i s t s t h e paper o f G o t t l i e b and H e n d r i c k s ( 1 9 4 5 ) became a v a i l a b l e . These a u t h o r s r e p o r t t h a t n i t r o b e n z e n e o x i d a t i o n o f mucks y i e l d e d no c h a r a c t e r l z a b l e p r o d u c t s .  (45) TABLE IX NITROBENZENE OXIDATION OF GYMNOSPERMS (CREIGHTON ET AL,1944) .PLANT  KLason Lignin%  Total V a n i l l i n SyringalAldehydes % dehyde %  Ratio Vanillin: Syringald-  Pioea glanea (White Spruce)  28.6  23.7  23.5  None  Tsuga Canadensis (Hemlock)  31.1  23.2  22.1  None  -  Pinus strabus (white pine)  34.9  20.1  18.5  None  -  Thuja p l i c a t a (red cedar)  33.9  24.6  24.0  None  -  Toxus Canadensis (Gjrounnl Hemlock)  32.5  22.0  20.7  None  -  NITRO BENZENE OXIDATION OF ^COTYLEDONS AQQar rubrum (Red maple)  22.0  46.0  10.2  34.7  1:34  32.1  1:34  Populus tremuloids 17.4 (aspen)  44.7  9.4  Betuia luten (yellow birch)  19.6  44.9  11.0  33.7  1:31  Froxinus americana (white ash)  18.5  48.6  10.5  37.2  1:33  NITROBENZENE OXIDATION OF MONOCOTYLEDONS Rye straw  20.2  30.5  14.1*^  Corn cobs  13.8  21.4  17.1  Corn stalks  19.9  17.8  9.5  15.3  1:00  6.0  1:04  7.8  1:0,8  a n i l l i n i n monocotyledons also contains somepj-hydroxybenzalde hyde.  the hydrozone.  Pretreatment  by steam d i s t i l l a t i o n of  the bomb contents before extraction with benzene should remove the nitrogenous compounds.  Since organic matter  i s higher i n ash than plant material and therefore heavier there may be d i f f i c u l t y i n obtaining thorough mixing of the organic matter with the reacting solution.  I f such  were the case increasing the severity of a g i t a t i o n beyond 300 strokes per minute might prove advantageous.  The  poss-  i b i l i t y exists that oxidation of the C6-C3 u n i t s i n organic matter l i g n i n does not stop at the aldehyde stage but i s carried, as i s suggested by the Estes t e s t , to v a n i l l i c syringic acids.  I f t h i s theory can be  and  substantiated,methods  for determination of the guaioyl and syringji r a d i c a l s as the acids might be desirable. HYPOIODITE OXIDATION OF ORGANIC MATTER LIGNIN Norman and Peevey (1939) have suggested the use of hypoiodite as a means of studying l i g n i n d i s t r i b u t i o n i n the s o i l .  With t h i s reagent as an oxidizing agent, consider-  able differences were reported i n respect to tne r e a c t i v i t y of the organic matter i n the horizons of a p r o f i l e and i n the surface layers of the great s o i l groups.  In view of  t h e i r results i t was thought advisable to study the hypoiodite oxidation of the B.C.  s o i l s to see whether or not t h i s  reaction could be used to characterize the organic matter content of these s o i l s .  (47) S o i l Samples Used (a)  The samples of s o i l as used f o r proximate analysis  were reserved f o r t h i s study. (b)  The l i g n i n residues from the proximate analysis  were included f o r comparison. Experimental The method i s that outlined by Norman (1943). One-half to f i v e grams of s o i l , depending on the carbon content, was placed i n a small glass-stoppered b o t t l e (100-125 mis.) and 25 mis. of water added.  After a further addition of  5 ml. of Et-Hcl solution (1 gram EC 10 ml. cone. H c l made up to 100 ml.) the mixture was shaken and allowed to stand over-night.  One m i l l i l i t e r of 1% starch solution  was added and any free T% released from the K I t i t r a t e d with o.l'N NagSOj from a burette.  This correction was  found necessary since certain s o i l s were found capable of oxidizing KI to Ig. (not  Th  e  volume of NagSOj was recorded,  more than .5 ml. of t h i s work and usually .1 ml.)  Water was then added from a burette so that the veluBwof l i q u i d i s brought up to 35 ml. (25+5*l+x sulphite t y waters35 ml)  F i f t e e n mis. of 2N NaOH was pipetted  i n followed by 50 ml. of .IN I . 2  After being shaken, the  bottle was placed i n the dark and shaken by hand at approximately 10 minute i n t e r v a l s /  Aliquots of 10 ml. were  withdrawn at the end of 1 hour and a c i d i f i e d with 10 ml. @f IN H S 0 9  A  f o r t i t r a t i o n with .03 N N a S 0 , 9  9  (48)  The iodine uptake was expressed as millfcequivalents of Ig per 100 grams of s o i l , per unit of organic carDon i n the soil.  The Nature of the Reaction Between Hypoiodite and S o i l Organic Matter. In a l k a l i n e solutions Ig undergoes the following reactions: 2Na0H + I -» NalO + 2NaI 2  3NaI0  + H0 2  ~*> NalOj + 2 Nal  Iodine behaves d i f f e r e n t l y from other members of the halogen family since the conversion of hypoiodite to iodate i s complete within one-half hour.  Therefore, the  reaction of hypoiodite with s o i l organic matter i s not a simple quantitative one, but one which i s considerably affected by concentration of reactants.  Also, the actual  nature of the reaction with organic matter i s not c l e a r l y understood.  Norman (1943)  suggests that the point of  attack may be the phenol OH group i n the l i g n i n molecule. However, i t i s known that hypoiodite oxidized the aldore group with formation of the corresponding acid.(Goebel 1927). Again, the CHj-C-  group i s attacked to form iodoform i n  the w e l l known iodoform test (AOAC 1945).  In the present  study a l l the reaction b o t t l e s smelled strongly of iodoform i n d i c a t i n g that at least some of the hypoiodi-ce was converted to t h i s compound.  Thus a q u a n t i t a t i v e d e t e r m i n a t i o n o f  groups by means of iodoform may be valuable i n  (49) characterizing organic matter.  At best then, the procedure  i s e n t i r e l y empirical with a l l the shortcomings of empi r i c a l determinations, with the a d d i t i o n a l disadvantage that the exact nature of the reaction i s not at present understood Data and Discussion of Data. The data f o r hypoiodite oxidation expressed as the ME of I2 P  e r  i n Table X.  1°0 grams of s o i l per u n i t of C. i s presented In both the s o i l and l i g n i n residues, a rough  c o r r e l a t i o n e x i s t s between the a c t i v i t y f a c t o r (me Ig j and the percentage organic carbon.  I n the " l i g n i n residues"  there i s a tendency f o r the A^ horizons of grassland s o i l s to show greater a c t i v i t y than that from the corresponding A  Q  horizon.  But, i n the case of P i n c h i , a grassland s o i l ,  the reverse i s true.  This fact may possibly be explained  by error i n sampling. Norman (1944) pointed out that forest s o i l s showed higher r e a c t i v i t y than the grassland s o i l s and t h i s i s borne out by the data presented i n Table X. Barret association^an exception^there  With the  i s a marked tendency  for the wooded s o i l s to show greater r e a c t i v i t y from the AQ to the A^ horizon.  passing  No r e a l differences are  brought out i n the hypoiodite oxidation of l i g n i n residues.  TABLE X  Soil Zone  HYPOIODITE OXIDATION OF 1? SOILS AND LIGNIN RESIDUES.  Soil Association  Oven Dry S o i l Horizon  Dawson  A  Nulki Shallow Black  I lOOg  m  e  2  me  l2/100 g  Oven Dry L i g n i n residue %0  108.0  6.90  AjUpper  12.5  87.0  6.93  Nulki  A^Lower  15.6  94.5  6.03  Pinchi  A  o  25.0  159.0  6.36  Pinchi  A  l  11.3  90.0  8.82  Driftwood  A  l  33.2  6.40  -  Telkwa  A  o  115.5  6.06  16.2  Telkwa  A  l  A  o  A  l  A  o  A  l  A  o  5.20  18.8 8.10  88.5  m e I Ig  2/lOO g  lOOg  15.6  l  me  14.4  75.0  5.49  58.5  7.95  13.4  75.0  4.71  16.8  138.0  9.09  45.0  6.36  7.36  7.00  5.04  10.8  -  -  150.0  9.24  57.0  11.34  102.0  3.0  27.0  8.27  306.0  4.92  16.2  7.20  306.0  4.53  Alberta Transition tt Barret Barret Vanderhoof Vanderhoof  A  l  30.4 5.00 41.8 4.48 58.3 •  3.44  258.0  8.49  35.4  7.08  450.0  10.8  41.1  9.78  384.0  6.60  34.0  3.26 62.4 2.24 67.7  •  35.4  10.2  2.43  27.0  -  Alberta Grey Wooded  A  o  A  l  Doughty  A  o  Fort St.James  A  l  Lakelse  A  o  ii  —  - ~  -  •  21.6 4.15 41.6 6.15  198.0  9.18  39.0  9.96  318.0  7.65  78.0  12.7  20.6 3.04 48.1 5.71  270.0 20.4  13.1 7.14  480.0  10.0  108.0  18.6  Pacific Coast  58.2  486.0  8.34  68.2  408.0  5.98  o  (51)  Conclusions The nitrobenzene oxidation c a r r i e d out on rye straw, spruce wood and f i r wood yielded 10-25%, based on i n i t i a l l i g n i n , of the aldehydes v a n i l l i n and syringaldehyde. Production of these aldehydes depended upon the maintenance of s p e c i f i c temperature and speed of shaking conditions during the oxidation. No aldehydes were formed i n the oxidation of s o i l organic matter although the same technique f o r oxidation of rye straw and the woods was used.  I t i s suggested -  that the chemical groups i n the organic matter l i g n i n involved i n the oxidation process are changed i n some way upon decomposition so that the reaction i s blocked. Hypoiodite oxidation of the 19 s o i l s and t h e i r l i g n i n residues from Part A show no consistent differences. Therefore, the value of t h i s t e s t f o r characterization of the organic horizons of B r i t i s h Columbia s o i l s i s questioned.  (52)  PART 0  DETERMINATION OF SOIL PIGMENT Review of Literature  The fact that solutions of s a l t s ammonium hydroxide and sodium hydroxide w i l l extract from organic matter a jet black to brown pigment or humus has been known for a long time.  A great many ideas have been put f o r t h  concerning the nature of humus but as yet very l i t t l e i s known about i t s true chemical nature. Gortner (19l6a) concluded that humfls i s not a t y p i c a l s o i l product since s i m i l a r extracts can be made from undecomposed plant materials. He further pointed out that the pigment content of organic s o i l s i s much higher than that of undecomposed vegetable material so i t may be concluded that humus extracted from s o i l does not consist e n t i r e l y of pigmented dompounds but contains a large proportion of almost colourless substances u s u a l l y masked by the ooloured compounds.  Using d i f f e r e n t  extracting solutions he (19l6b) observed that 4% sodium hydroxide, although i t dissolves approximately the seme weight of humus, does not dissolve the same quantity of coloured compounds as does 4% ammonium hydroxide.  In an  attempt to procure the pure pigment from the ammonia extracts he secured a product containing 37-47% ash (^Humus i n t h i s paper r e f e r s to the organic substances of s o i l s soluble i n ammonium and sodium hydroxides. )  (53) which he explained may be a contributing f a c t o r i n the colour phenomena.  The formation of humus i n the s o i l  i s described by Baoklay (1921) who states that the coloured material i s the r e s u l t of carbohydrates reacting a  with mineral acids to form hydroxymethylfurfural condenses to form humus.  which  Naturally, such an explanation  i s highly t h e o r e t i c a l and has been proven only to the point that hydroxymethylfurfural  w i l l give a black  condensation product. According  to Gillam (1940) that f r a c t i o n of the  s o i l organic matter remaining following peptization by ammonia and p r e c i p i t a t i o n by acid and insoluble i n 95% ethanol i s the s o i l black pigment.  Various pigment  f r a c t i o n s , although i s o l a t e d from s o i l s of d i f f e r e n t s o i l groups, when subjected to such determinations as methoxyl content, acetyl number and $Qt@ntiORSt*?io titration  were found to be remarkably consistent i n  chemical and physical properties.  This suggests that the  same central neucleus i s present f o r each pigment. The formation of s o i l pigment as extracted by ammonia i s believed to be a function of such f a c t o r s as climate, vegetation, topography, drainage and b i o l o g i c a l activity.  Since i t i s w e l l known that the zonal  d i s t r i b u t i o n of s o i l s i s also based on these factors, methods f o r measuring the pigments have been worked out and the r e s u l t s correlated with the s o i l zones. Hock (1957) found that the humus extracted from Podsol and Black Earth s o i l s with sodium f l u o r i d e and sodium  (54)  oxalate gave v a s t l y d i f f e r e n t oolourtone values "farbtonwert" as determined by a mercury vapor lamp. He suggests that behaviour of humus extracts on exposure to the mercury vapor lamp or other photoelectric measuring instruments could be used as a c r i t e r i o n of s o i l  type.  Gillam (1938) i n a study o f pigment values i n r e l a t i o n to temperature and p r e c i p i t a t i o n demonstrated that f o r every f a l l of l8°F i n mean annual temperature along the two isohyetal l i n e s through the Central Plains the humus colour increases two or three times.  With  increasing p r e c i p i t a t i o n along an isothermae l i n e he observed that the humus colour increases proportionally. In t h i s work, s o i l type and texture were constant. Experimental In the present work the colour value of ammonium hydroxide extracts of the 19 s o i l s previously described i n Part A were studied with a photoelectric  colourimeter.  Since a quantitative extraction o f s o i l pigment with d i l u t e ammonia i s well nigh impossible Gillam 1938, Shorey 1930)  (Gartner 1916a,  a modification of an i n d i r e c t  method suggested by Gillam (1938) was used.  In this  method a colourimetric procedure was employed since many workers including Alway and Pinckney (1911), Carr 1917» and Eden (1924) have concluded that i t i s sound i n p r i n c i p l e . The method as modified i n t h i s laboratory i s as follows: ten grams of a i r dry s o i l was mixed with an equal weight of pure quartz sand and placed i n a leaching apparatus suggested  (55) by Shollenberger (1945).  I t was then leached with 1^  hydrochloric acid u n t i l no calcium could be detected i n the leachate. required.  One hundred f i f t y to 200 mis. were usually  D i s t i l l e d water was then percolated through  the s o i l u n t i l a l l chloride ions were removed, about 150 ml. being required f o r t h i s treatment.  Finally a  solution consisting of 4% ammonia hydroxide, and 2% ammonium carbonate was percolated through the s o i l and exactly 250 ml. of the j e t black extract retained. The ammonia solution was fed through the extractor at a constant rate of 1.5 me per minute, t h i s rate being c l o s e l y adjusted by screw-clamps on the delivery tubes. Duplicate 10 ml. portions of the extract were determined gravimetrically f o r soluble organic matter and the percentage of ash free humus calculated f o r the whole sample.  The required volume of extract was removed and  diluted to 100 ml. to give 1 part of pigment and 10,000 parts of solution or 100 ppm of pigment. values of the extracts were determined  The colour  i n a Fisher  Colourimeter. Data and Discussion of Data. From the data assembled i n Table XI a comparison of hygroscopic c o e f f i c i e n t , percentage humus and humus colour can be made f o r the various s o i l types.  The  hydroscopic c o e f f i c i e n t i s included to show the c o l l o i d a l nature of the s o i l s which i n a rough way i s a c r i t e r i o n of texture (Russel and McRuer 1927). the A  Q  I t w i l l be seen that  horizons have a hygroscopic c o e f f i c i e n t higher than  TABLE XI - HUMUS COLOUR OF THE 19 SOILS UNDER STUDY Zone  Association  Horizon  Dawson  Hygroscopic % Organic c o e f f i c i e n t Matter  % Humus  Humus Colour Value.  5.47  24.9  4.20  54.0  Nulki  AjUpper  4.96  20.9  2.75  66.0  Sha How  Nulki  A^Lower  4.17  24.9  3.25  68.0  Black  Pinchi  A  7.61  42.8  3.72  50.0  Pinchi  0  A  l  6.71  19.5  3.5  60.5  A  l  5.32  8.9  3.7  57.0  A  o  71.8  7.09  19.0  Barret  A  l  6.0  1.25  23.5  Gre y  Vanderhoof  A  o  98.1  7.50  15.5  Wool e d  Vanderhoof  A  l  2.91  21.5  A  o  5.50  22.0  3.96  26.0  71.9  8.11  16.0  Driftwood Barret  11.4 3.51 12.4 3.10  5.92  Alberta Grey Wooded  6.64  37.1  Alberta Grey Wooded  l >  A  7.13  Doughty  A  o  Fort St.James  A  l  7.49  10.6  3.5  55.0  V  5.72  32.2  5.00  70.1  3,61  14.0  3.2S  o  7.83  60.3  4.59  39.0  n  Al  3.97  2.00  45.0  Lakelse  A  90.1  8.08  22.5  -  7.25  25.2  Grey Black Telkwa Transition Telkwa  i  2.76 12.3  -  0O.5  Alberta Grey Black Transition  A  8.62  Pacific Coast  o  U.B.C. Forest L i t t e r  13.2  _  -  (57)  (58)  -the Ai_ horizon samples. The percentage humus i n a l l samples i s f a i r l y well correlated with percentage organic matter.  However,  more humus i s extracted per u n i t i n the A l horizons than i n the A  Q  horizons.  The humus colour values are g r a p h i c a l l y i l l u s t r a t e d i n Figure IV.  These oolour values show very s i g n i f i c a n t  differences between the forest s o i l s (Grey Wooded and P a c i f i c Coast) and the grassland s o i l s (Shallow Black and Transitional). both the A  Q  The differences manifest themselves i n  and A^ horizons as i s seen by examination  of Figure IV. Attention i s drawn to the fact that the s o i l s of the Black-Grey T r a n s i t i o n Zone show humus colour values of the same order as the Shallow Blaok soils.  Although Fort S t . James association i s t e n t a t i v e l y  c l a s s i f i e d as a Grey Wooded s o i l the high humus colour value suggests that i t might be placed i n the T r a n s i t i o n Zone.  The nature of vegetation and p r o f i l e developement  of t h i s s o i l also supports t h i s suggestion. I t w i l l be seen that the humus colour of the A-^ horizons are consistently higher than that of the corresponding A  Q  horizons.  This i s i n l i n e with Gortner's  (1916a 19l6b) observations that humus colour increases with decomposition.  (59)  RELATIVE  HUMUS  COLOR  DAHSON  o  NULKI  PINCHI  DRIFTWOOD  TELKWA  g  on  •v 111 11TA TRANSITION  ax BARRET  3D f-ri  VANOCR  O  ALTA.  ROOF  GRCY  O  WOODED  n  DOUGHTY  O  O  fr. j r .  jAMa  5  > x  ^  roRCST  LITTER  s  O JO  N O  Z.  o X O X)  N O  (60)  Conclusion Relative humus colour of ammonium hydroxide  extracts  provides a ready means of distinguishing between the organic matter of forest and grassland s o i l s .  In a l l  s o i l s examined, regardless of zones increased decomposition i n the Aj_ horizons i s shown by a higher humus colour value than the corresponding A  horizon.  (61) SUMMARY. Part A.Carbon oontent, carbon-nitrogen r a t i o .and a proximate analysis were determined on the organic matter of some representative British. Columbia and Alberta zonal s o i l s .  Comparing s o i l zones carbon content and  hence percentage of organic matter was higher i n the A  Q  horizons of the Grey Wooded s o i l s while that i n the  A i horizons i s higher i n the Shallow Black and Transitional soils.  The carbon-nitrogen r a t i o was narrower i n  the grassland s o i l s .  Although proximate  analysis  did not show s t a r t l i n g differences between zones, certain differences seem to be s i g n i f i c a n t : (a) Higher " l i g n i n " nitrogen complex and l i p i d content i n P a c i f i c Coast and Grey Wooded s o i l s . (b) Percentages of "hemicellulose" and " c e l l u l o s e decrease i n passing from the A© to the A i horizon. (c) "Lignin and nitrogenous complexes concentrate i n the A i horizons. Part B.Nitrobenzene oxidation of s o i l organic matter from various sources yielded no c h a r a c t e r i s t i c oxidation products although excellent y i e l d s of v a n i l l i n and syringaldehyde were obtained from oxidation of spruce wood, f i r wood and rye straw.  I t i s suggested that the  (62)  groups involved i n the nitrobenzene  oxidation reaction  are destroyed during decomposition of plant materials, or that, some shortcomings i n technique were responsible for the i n a b i l i t y to i s o l a t e c h a r a c t e r i s t i c compounds. Hypoiodite oxidation of zonal s o i l s and t h e i r l i g n i n residues showed ho consistant differences i n the nature of the l i g n i n .  Oxidation by hypoiodite i s quest-  ioned as a means of detecting differences i n the constitution of the organic f r a c t i o n of B.C. s o i l s . Part  CRelative humus colour i s shown to be higher i n  the Shallow Black and T r a n s i t i o n a l s o i l s . may be used as a c r i t e r i o n of s o i l type.  This difference Also the A]_  horizons of a l l s o i l s examined show a higher humus colour value than the corresponding AQ horizon.  (63) Alexander, L.T., and Byers, H.G, 1932 A oriticfc<i laboratory review of the methods of determining organic matter and carbonates i n s o i l . U.S. Dept. Agric. Tech. B u i . 317. Alway, F.J., and Pinckney, R.M. 1911.' The photometric and colorimetric determination of humus. Nebr. Agr. Exp. Sta. 25th Ann. Rept. * Association of O f f i c i a l A g r i c u l t u r a l Chemists, Methods of Analysis. 5th ed. 19*5. Washington, D.C. B a r t l e t t , J.B. and Norman, A.G. 1939. Changes i n the l i g n i n of some plant materials as a r e s u l t of decomposition. Proo. S o i l S c i . Soc. of Amer. 3:210-216. Beokley, V.A.1921. Formation of humus. Jour A g r i c . S c i . 11:70-77. Boruff, C.S. and Buswell, A.M. 1934. The aneisrabio fermentation of l i g n i n . Jour Amer. Chem. Soc. 56:886. Bouyoucos, G.J. 1934. Method for determining the degree of decomposition that unknown decayed vegetable organic materials have alreadyundergone i n nature. S o i l S c i . 38:477-82. Brickman, L., Pyle, J . J . , McCarthy, J.T.,Hibbert, H.1939. Studies on l i g n i n and related compounds XXXIX. Ethanolysis of spruce and maple woods. Jour. Amer. Chem. Soc. 61:868-869. Carr, R.H. 1917. I s humus oontent of a s o i l a guide to f e r t i l i t y . S o i l S c i . 3:515-524. Cook, F.D. 1945. The microbiological a c t i v i t y of p r o f i l e s of Pineview, Vanderhoof and Nulki Clays. Unpublished undergraduate t h e s i s . University of B r i t i s h Columbia. Creighton, R.H.J., Gibbs, R.D. and Hibbert, H.1944. Studies on l i g n i n and related compounds LXXV. Alkaline nitrobenzene oxidation of plant materials and application to taxonomic c l a s s i f i c a t i o n . Jour. Amer. Chem. Soc. 66:32-37*  (64)  Creighton, R.H.J, and Hibbert, Harold, 1944. Studies on ^ l i g n i n and related compounds. LXXYI. A l k a l i n e nitrobenzene oxidation of corn stalks. I s o l a t i o n of p-hydroxybenzaldehyde. Jour. Atner. Chem. Soo. 66:37. Eden, T.A. 1924. A note on the colorimetric estimation of humic acid i n mineral s o i l s . Jour A g r i c . S c i . 14:469-472. Estes, D. 1917. A new quantitative test and ooloremetric method f o r the estimation of v a n i l l i n . Ind. Eng. Chem. 9:142-144. Farstad, L., and L a i r d , D.G. 1943. S o i l survey of the central i n t e r i o r of B.C. Unpublished report, U n i v e r s i t y of B.C. Fowler, R.H. and Wheeting, 1941. Nature of organic matter i n western Washington P r a i r i e s o i l s as influenced by differences i n r a i n f a l l . Jour. Amer. Soc. of Agron. 3 3 1 3 - 3 3 . :  Freudenberg, K. Harder, M. and Markert, L. 1928 Ber. 6 l : 1 7 6 0 , as c i t e d i n Freudenberg, K. Polysacchorides and L i g n i n . Ann. Rev. Biochem. 8:81-112. Freudenberg, K. 1939. Polvsacchorides and l i g n i n . Ann. Rev. Biochem. 8:81-112. Freudenberg, K. Lautseh and Ingler, 1940-Ber.,73:167. as c i t e d i n Creighton et a l . Jour Chem. Soc.66:34. Gillam, W.S. 1939. The geographical d i s t r i b u t i o n of s o i l black pigment. Jour. Amer. Soc. Agron. 31:371-387. Gillam, Sherman, W. 1940. A study on the chemical nature of humic a c i d . S o i l S c i . 49:433-453. Gross, R.A. 1946. The composition and c l a s s i f i c a t i o n of forest f l o o r s and related s o i l p r o f i l e s i n Saskatchewan. S c i . Agric. 26;603-621. Goebel, W.F. 1927, on the oxidation of glucose i n alkaline solutions of iodine. Jour. B i o l . Chem. 72:801-807.  (65) Gortner, R.A. 1916. a. The organic matter of the s o i l : I Some data on humus, humus carbon and humus nitrogen. S o i l S c i . 2:395-440. Gortner, R.A. 19l6b. The organic matter of s o i l : I I A study of carbon and nitrogen i n seventeen successive extracts; with some observations on the nature of the black pigment. S o i l S c i . 2:539-548. Gottlieb, S., and Hendricks, S.B., 1945. Organic matter as r e l a t e d to newer concepts of l i g n i n chemistry. S o i l S c i . Amer. Proc. 10:117. Hibbert, H. 1942. L i g n i n . Ann. Rev. Biochem. 11:183. Hock, A. 1937 Humus equals Untersuchungen an typischen schuarzerde equals bodenbildungen. Ernahr. P f l a n z 33:337-342. Kurschner, 1928. J . Prokt. Chem. 118:238 as c i t e d in Tomlinson and Hibbert 1936. Jour Amer. Chem. Soc. 58:345-348. Levine, M. 1935. U t i l i z a t i o n of A g r i c u l t u r a l wastes; microbial decompositions. Ind. & Eng. Chem. 27:194-200.  l i g n i n and  Lunt, H.A. 193t>. Carbon-organic matter factor i n forest s o i l humus. S o i l S c i . 32:27-33. M i l l e r , H.C., Smith, F.B. and Brown, P.E. 1936. The base exchange capacity of decomposing organic matter. Jour. Amer. Soc. Agron. 25:753-766. McGeorge, W.T. 1934. Organic base exchange compounds i n s o i l s . Jour. Amer. Soc. Agron. 25:575-9. M i t c h e l l , J . 1932. The o r i g i n , nature and importance of s o i l organic constituents having base exchange properties. Jour. Amer. Soc. Agron. 24:256-275. Norman, A.G. 1937. The biochemistry of c e l l u l o s e , the polyuronides, l i g n i n and C. Oxford at the Clarendon Press.  *(66)  Norman, A.G. 1942'. The chemistry Of s o i l organic matter. I I Hypoiodite oxidation of the organic matter of some s o i l p r o f i l e s . S o i l S c i . 56:223-233. Norman, A.G., and Bartholomew, W.V. 1943. Chemistry of s o i l organic matter: I D i s t r i b u t i o n of uronic carbon i n some s o i l p r o f i l e s . S o i l S c i . 56:143-150. Norman, A.G. and Jenkins, S.H. 1933. A new method f o r the determination of c e l l u l o s e , based on observations on.the removal of l i g n i n and other incrusting materials.. Biochem. Jour 27:8l8 -831. Norman, A.G. and Moody, J.E. 1940. The a p p l i c a t i o n of d e l i g n i f y i n g procedures to s o i l organic matter. S o i l S c i . of Amer. Proc. 5:171-175. Norman, A.G. and Peevy, W.J. 1939. •"•'he oxidation of s o i l organic matter with hypoiodite. Proc. S o i l S c i . Amer. 4:183-188. P h i l l i p s . Max. 1927. The chemistry of Lignin: I Lignin from corn cobs. Jour. Amer. Chem. Soc. 49:2037. Pinck, L.A. and A l l i s o n , F.E. 1943. l i k e complexes by fungi. S o i l S c i . 57:155-161.  The synthesis of l i g n i n -  Russel, J.C.< and McRuer, W.G. 1927. 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Decomposition of the various chemical constituents of complex plant materials by pure cultures of fungi and b a c t e r i a . Arch. Mikrob. 2:136-154. Waksman, S.A. Tenney, E.G. and Stevens, K.R.1928. The role of micro-organisms i n the transformation of organic matter i n f o r e s t s o i l s . Ecology. 9:126-144. Waksman, S.A. and Diehm, R.A. 1931a On the decomposition of hemicelluloses by micro-organisms. I I Decomposition of hemicelluloses by gungi and actinomyoes. S o i l S c i . 32:97-117. Waksman, S.A. and Diehm, R.A. 1931 b. On the decomposition of hemicelluloses by micro-organisms. I l l Decomposition of various hemicelluloses by aerobic and anearabic bacteria. S o i l S c i . 32:119-139.  (68)  Waksman, S.A., and Hutchings, I . J . 1935. Chemical - nature of organic matter i n d i f f e r e n t s o i l types. S o i l S c i . 40:347. Waksman, S. and Hutchings, I . J . 1936. l i g n i n by microorganisms. S o i l S c i . 42:119.  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