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Manganese status of some Lower Fraser Valley soils developed from alluvial and marine deposits Safo, Ebenezer Yeboah 1970

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MANGANESE STATUS OF SOME LOWER FRASER VALLEY SOILS DEVELOPED FROM ALLUVIAL AND MARINE DEPOSITS by EBENEZER YEBOAH SAFO B.Sc. (Agr ic . ) Univers i ty of Science and Technology, Ghana, 1967 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE i n the Department of SOIL SCIENCE We accept th i s thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA August, 1970 - i v -In presenting th i s thesis i n p a r t i a l fu l f i lment of the requirements for an advanced degree at the Univers i ty of B r i t i s h Columbia, I agree that the Libra ry s h a l l make i t f ree ly ava i lab le for reference and study. I further agree that permission for extensive copying of th is thesis for scholar ly purposes may be granted by the Head of my Department or by h is representat ives. I t i s understood that copying or pub l ica t ion of th i s thesis for f i n a n c i a l gain s h a l l not be allowed without my wr i t t en permission. Department of S o i l Science The Univers i ty of B r i t i s h Columbia Vancouver 8, B . C . , Canada Date: August, 1970 - i i -ABSTRACT A study was undertaken to determine the manganese status of some Lower Fraser Va l l ey s o i l s developed from a l l u v i a l and marine deposi ts . Mn fract ions i n s i x s o i l s and i n the i r p a r t i c l e s ize separates were determined by atomic absorption spectrophotometry. Water soluble Mn ranged from 0.5 to 1.4 ppm; Exchangeable Mn from 0.5 to 15.0 ppm; Hydroquinone reducible from 0.7 to 119.5 ppm; Tota l Mn from 82.0 to 957.5 ppm; and "Act ive Mn" from 3.2 to 129.8 ppm. These ranges were s imi l a r to reported values, except that . the study f a i l e d to f ind the high l eve l s of t o t a l Mn reported by Baker on some s o i l s from the same area. Generally water soluble and exchangeable Mn showed l i t t l e v a r i a t i o n wi th in p r o f i l e or between s o i l s . In four out of the s i x p r o f i l e s reducible and t o t a l Mn were higher i n the parent mater ia l than i n the surface horizons. However, there was no sa t i s fac tory f i t for a number of the p r o f i l e s to the four d i s t r i b u t i o n patterns suggested by Leeper. Values for EDTA extractable and "ac t ive" Mn i n two p r o f i l e s suggest that both f ract ions of Mn represent the same chemical form. How-ever, further resu l t s suggest that the two Mn fract ions are d i f f e r en t . In nearly a l l samples with high organic matter content EDTA extracted more Mn after removing "act ive Mn" than d i r ec t ex t rac t ion with EDTA, supporting suggestions that EDTA extracts chelated Mn and also causes some dispers ion of s o i l p a r t i c l e s . - i i i -Sonic d ispers ion led to increased recovery of a l l forms of Mn, more espec ia l ly reducible and t o t a l Mn. The resu l t s suggest that u n t i l more i s known about sonic d ispers ion i t i s unwise to assume that no modif icat ion of s o i l consti tuents takes place. S t a t i s t i c a l techniques were used to examine the re la t ionsh ip between Mn d i s t r i b u t i o n and parent mater ia ls , pH, organic matter content and ca t ion exchange capaci ty . These analyses showed that the l e v e l of Mn f ract ions i n the s o i l cannot be predicted by any s ingle fac tor , but only by a number of s o i l factors i n combination. The p o s s i b i l i t y of bu i ld ing up a computer model to predict Mn d i s t r i b u t i o n i s suggested. The s ign i f icance of s o i l Mn d i s t r i b u t i o n i n terms of plant requirements i s discussed. Plant ava i lab le Mn i n these s o i l s , estimated by 0.02 M C a C ^ ex t rac t ion , ranged from 0.5 to 10.7 ppm. This was very s i m i l a r to that for exchangeable. Based on data i n the l i t e r a t u r e these s o i l s were c l a s s i f i e d into manganese-deficient and-suff ic ient categories . Using ext rac t ion techniques only, various Mn pools were established for these s o i l s according to the chemical pool concept proposed by V i e t s . These pools and the i r possible r e l a t i o n to Mn a v a i l a b i l i t y are discussed. I t was suggested that a further study was necessary to es tab l i sh a c o r r e l a -t i o n between these Mn pools and plant Mn requirements and also to reveal the e q u i l i b r i a and rates of interconversion ex i s t i ng between the established pools as found under the s o i l conditions of the Lower Fraser V a l l e y . V ACKNOWLEDGMENTS The wr i t e r i s grateful to the Government of Canada for f inancing h i s study at the Univers i ty of B r i t i s h Columbia through the Commonwealth Scholarship and Fellowship P lan . Special thanks are due to Dr. L . E. Lowe, Associate Professor, Department of S o i l Science, who gave valuable guidance at a l l stages of the study and preparation of th i s thes i s . Thanks are extended to Dr. C. A. Rowles, Professor and Chairman of the Department, for h i s advice and recommendations during the planning stages of the study, and also to the other members of my thesis committee, Dr. G. W. Eaton, Depart-ment of Plant Science and Dr. J . W. Murray, Department of Geology. The assistance of Mr. B. von Spindler i n the use of the Atomic Absorption Spectrophotometer i s g ra te fu l ly acknowledged. To my wife Janet, I extend my deepest appreciat ion for her constant patience and encouragement throughout the period of my study. - v i -TABLE OF CONTENTS Page INTRODUCTION 1 LITERATURE REVIEW 3 MATERIALS AND METHODS • 27 RESULTS AND DISCUSSION 31 D i s t r i b u t i o n of the Forms of S o i l Manganese 31 D i s t r i b u t i o n of Manganese between P a r t i c l e Size Separates 39 Relat ionship between Manganese D i s t r i b u -t i o n and Parent Ma te r i a l s , pH, C . E . C . , and Organic Matter Content 43 Signif icance of S o i l Manganese D i s t r i b u t i o n i n Terms of Plant Requirements 49 SUMMARY AND CONCLUSIONS 58 LITERATURE CITED 61 - v i i -LIST OF TABLES Table Page I (a) Some Phys ica l and Chemical Propert ies of the S o i l s Derived from A l l u v i a l Deposits 32 I (b) Some Phys ica l and Chemical Propert ies of the S o i l s Derived from Marine Deposits 33 I I D i s t r i b u t i o n of S o i l Manganese (ppm) 34 I I I "Ac t ive" and EDTA Extractable Mn 38 IV Water Soluble and Exchangeable Mn i n Dispersed and Undispersed S o i l 41 V Tota l Mn i n Dispersed and Undispersed S o i l 41 VI Hydroquinone Reducible Mn i n Dispersed and Undispersed S o i l 42 VI I Act ive and EDTA Extractable Mn i n Dispersed and Undispersed S o i l 42 V I I I Summary of Results from Simple Regression Analys is 45 IX Exchangeable Mn as Apparent Percent of C . E . C . 47 X Regression Equations of Mn Fract ions on S o i l Factors and Related Data 48 XI 0.02 M C a C l 2 Extractable Mn i n Rela t ion to other Forms of Mn 50 - v i i i -LIST OF FIGURES Figure Page I The Manganese Cycle i n S o i l (After Fujimoto and Sherman, 1948) 23 I I The Postulated Pools of Micronutr ient Cations i n S o i l (after V i e t s , 1962) 53 I I I Poss ib le Pools of Mn i n the Lower Fraser Val ley So i l s 55 INTRODUCTION Amongst the trace elements, manganese has received considerable a t tent ion i n recent years not only because of i t s function as a plant nutr ient and i t s important b i o l o g i c a l r o l e , but also because of i t s complex chemistry i n the s o i l . In both n u t r i t i o n a l and pedological studies i t i s important to know the forms i n which trace elements occur, and also the proportions of these forms i n the s o i l . In sp i te of the exhaustive study by a number of workers, the chemistry of s o i l manganese i s s t i l l comparatively obscure, and the f indings of d i f ferent workers often appear cont radic tory . . In a previous study of manganese d i s t r i b u t i o n i n some B r i t i s h Columbia s o i l s by Baker (1950), s o i l s from the Lower Fraser Va l l ey were found to contain higher amounts of t o t a l manganese than those from other areas of the Province. Since the manganese status of a s o i l depends on several factors inc luding parent ma te r i a l , pH, organic matter, moisture and the general oxidat ion-reduct ion state i n the s o i l , a more de ta i led examination of these factors as they operate under the condit ions of the Lower Fraser Val ley i s des i rab le . Furthermore, since there i s a marked difference between the. manganese d i s t r i b u t i o n of marine sediments and that of the f l u v i a l clays which have been deposited i n the fresh-water t i d a l area, these two parent materials are selected for the study. A complete study of manganese status of a s o i l and i t s r e l a t i o n to plant growth should b a s i c a l l y involve two phases:- the s o i l phase, - 2 -which establ ishes the manganese status of the s o i l , and the plant phase, which re la tes the s o i l manganese status to plant requirements. The present study emphasises the s o i l phase and has the fol lowing ob jec t ives : -1) . To determine the d i s t r i b u t i o n of the various forms of manganese both w i th in the p r o f i l e , and between s o i l f r ac t ions . 2) To examine the re la t ionsh ip between the manganese d i s t r i b u t i o n and other s o i l c h a r a c t e r i s t i c s , p a r t i c u l a r -l y - parent mate r ia l , pH, organic matter and ca t ion exchange capaci ty . - 3 -LITERATURE REVIEW I General Chemistry and Occurrence of Manganese i n Nature i ) General properties of manganese: Manganese i s r e l a t i v e l y abundant, cons t i tu t ing about 0.085% of the earth 's crust (Cotton and Wilkinson, 1962). I t i s the t r a n s i t i o n a l element immediately preceding i ron i n the per iodic tab le . I t exhib i t s mul t ip le valence and also resembles i ron i n some of i t s chemical proper t ies . Although manganese can ex i s t i n the oxidat ion s tates: +1, +2, +3, +4, +5, +6 and +7 (Remy, 1966), only +2, +3 and +4 are found i n nature, often wi th the metal i n mixed valence states i n the same oxide. The +2 (manganous) and +3 (manganic) states are bas ic , while the +4 state (ch ie f ly MnO^) i s amphoteric (Lingane, 1966). The d ivalent (+2) manganese i s the most important and generally speaking, the most s table oxidat ion state for the element (Cotton and Wilkinson, 1962). In neut ra l or ac id aqueous so lu t ion i t ex i s t s as the very pale pink hexaquo 2+ ion [Mn (E^O)^] , which i s quite res i s tan t to ox ida t ion . In basic media, however, the hydroxide, Mn(0H) 2 > i s formed and t h i s i s more e a s i l y ox id ized , by a i r for example, as shown by the p o t e n t i a l : Mn(OH)2 V Mn 2 0 3 .x 1^0 + ° ' 2 V Mn0 2 . y H 2 0 . i i ) Manganese minerals: The trace element content of a s o i l i s dependent on that of the rock from which the s o i l parent mater ia l was - 4 -derived and the process -of weathering, both geochemical and pedochemical, to which the s o i l forming materials have been subjected. Wangersky (1964) reviewed the geochemical cycle of manganese. Manganese bearing minerals 2+ of primary o r i g i n predominantly contain the Mn i o n , and on weathering, t h i s passes into so lu t ion as Mn(ECO^)^. The s t a b i l i t y of such compounds i s probably re la ted to the i r s o l u b i l i t y or more general ly to the hydrogen ion concentration of the i r environment which has an important bearing on 2~t" 3*4* A I the oxidat ion po ten t i a l required to convert Mn to Mn or Mn (Day, 1963). L i t t l e r e l i a b l e information on the mineralogy and chemistry of manganese oxides i n s o i l s was ava i lab le u n t i l Taylor et^  al_. (1964) made the i r study of Manganese nodules, concretions, and stains i n some Aus t r a l i an s o i l s . They examined 28 samples and found various amounts of l i t h i o p h o r i t e , b i r n e s s i t e , ho l l and i t e , todoroki te , and py ro lu s i t e . L i t h i o -phori te occurred i n neutra l to ac id subsurface s o i l s , whereas b i r n e s s i t e , although found i n both acid and a l k a l i n e s o i l s , was more common i n a l k a -l i n e surface horizons. Manganese oxides show a marked tendency to form co-prec ip i t a tes , which may be mixtures or complex oxides, with other heavy metals, p a r t i c u l a r -l y i r o n . This phenomenon may be ascribed to : (a) s i m i l a r i t i e s i n some chemical properties of the higher oxides of i ron and manganese, inc luding revers ib le oxidat ion-reduct ion, i n s o l u b i l i t y and the presence of pH -2+ dependent changes: (b) the closeness of the ion ic r a d i i of Mn (0.80 A) and Mn (0.66 A) to those of Fe (0.76 A) and Fe (0.64 A) respec t ive ly : and (c) perhaps c r y s t a l - l a t t i c e - induced valence changes (Ponnamperuma et a l . , 1969). - 5 -Published analysis of manganese mineral deposits (Hewett and F le i sche r , 1960; and Hewett et a l . , 1963) and of nodules from ocean f loor and shallow marine environments (Mero, 1962; and G r i l l , Murray and MacDonald, 1968) show s ign i f i can t concentrations of a large number of the trace elements of a g r i c u l t u r a l in te res t . There i s , however, no ava i l ab le evidence to show that the elements were so incorporated because of the scavenging properties of manganese minerals . Wadsley and Walkley (1951) suggested that prec ip i ta ted manganese oxides and hydroxides may adsorb a wide va r i e ty of ions present i n s o i l so lu t ions , and that these ions may eventually become incorporated i n the c r y s t a l s tructure of the Manganese minerals . In the i r study, Taylor et a l . , (1964) reported that with the possible exception of py ro lus i t e , an a c i d i f i e d hydrogen peroxide extract of a l l the samples contained varying amounts of A l , Ba, Ca, Co, Fe, K, L i , Mg, Na and N i . The associa t ion of trace elements, p a r t i c u l a r l y coba l t , wi th manganese minerals i n s o i l s has been studied by Taylor and McKenzie (1966). They reported that an average of 79% of s o i l cobalt was contained i n or associated with these minerals where they were present. I I Chemistry of Manganese i n the S o i l i ) Forms and d i s t r i b u t i o n of manganese i n the s o i l : Leeper declared i n 1947, that the chemistry of manganese i n the s o i l i s of in te res t for at least three reasons. F i r s t , i n some neutral and a l k a l i n e s o i l s , manganese i s i n s u f f i c i e n t l y ava i lab le to plants for healthy growth; - 6 -secondly, from some acid s o i l s plants absorb i t i n tox ic amounts; t h i r d l y , the d i s t r i b u t i o n of the various forms of the element i n the s o i l i s c lo se ly connected with the processes of s o i l formation. S o i l Sc ien t i s t s have usual ly considered manganese i n the s o i l 2+ to be present e s sen t i a l l y i n two forms:- (1) the b iva lent i o n , Mn -ex i s t i ng i n the s o i l so lu t ion or as an exchangeable ion or i n a non-exchangeable form, and (2) the inso luble higher oxides or hydroxides. These forms of s o i l manganese are thought to be i n dynamic equi l ib r ium with one another (Dion and Mann, 1946; Fujimoto and Sherman, 1948; Leeper, 1947; Sherman and Harmer, 1942) and probably with a t h i rd form, that which i s complexed by the s o i l organic matter poss ibly as chelates (Heintze, 1957; Heintze and Mann, 1949a; Hemstock and Low, 1953; walker and Barber, 1960). Piper (1931) pointed out the unique property of s o i l manganese of r e f l e c t i n g with r a p i d i t y the oxidat ion - reduction condi t ion of the s o i l . He concluded that the manganese i n s o i l ex is t s i n an oxidat ion - reduction equi l ib r ium and contended that the amount of manganous manganese i n the s o i l gives information on the s o i l ' s a b i l i t y to provide the plant with the required manganese. Invest igators do not agree to any great extent on the components of th i s manganese equi l ibr ium or c y c l e . The majori ty, however, notably Coppenet and Calvez (1952), Leeper (1947), and Serdobolski i (1950), sub-scr ibe to the theory that the a v a i l a b i l i t y of manganese to plants i s re la ted to th is equi l ibr ium c y c l e . 7 -The hypothesis of the existence of s o i l manganese i n a dynamic oxidat ion - reduction equi l ibr ium may be expressed as fo l lows : 2+ 2+ (a) Water-soluble Mn (b) exchangeable Mn •*-(c) ea s i ly reducible MnO^ + r e l a t i v e l y iner t manganic oxides. The ea s i l y reducible manganese dioxide would include compounds of every combining proportion from MnO to MnO^ (Leeper, 1935). The composition of these manganic compounds i s not constant but may be conventionally wr i t t en as the d iox ide , Mn0 2 , though Nafte l (1934) gave a n a l y t i c a l evidence for the formula M^O^ i n several s o i l s . The terms "manganic oxides" and "higher oxides" are used to include a l l formulae from Mn^O^ to Mn0 2 < Work by Nicholas and Walton (1942) shows how the composition of test-tube autoxidation product i s affected by the reac t ions : Mn02 + M n 2 + + H 2 0 £ M n 2 ° 3 + 2 H + Mn„0_ + M n 2 + + H.O •> Mn„0. + 2H + . 2 3 2 3 4 Use has been made of radioact ive Mn-54 i n an effor t to study the chemistry of manganese i n s o i l s . Being a gamma emitter of high energy with a h a l f - l i f e of 300 days, Mn-54 i s an e f f i c i e n t t oo l i n studying the turn-over of^manganese f e r t i l i z e r s added to s o i l s . Weir and M i l l e r (1962), employing the radioact ive isotope Mn-54, studied the equi l ibr ium cycle by fol lowing the isotopic-exchange reactions with s o i l manganese i n a manner s imi l a r to that used by Amer et a l . (1955) for s o i l phosphorus. Weir and M i l l e r reported several f i r s t - o rde r exchange reactions varying i n rate when water-soluble Mn-54 was allowed to equ i l ib ra te with s o i l manganese, but t he i r procedure was l a t e r reported to be erroneous (Reid and M i l l e r , 1962). - 8 -Many studies have been undertaken on forms of manganese, v i z : t o t a l , higher oxides, exchangeable and 'organic forms. The amounts and proportions of these forms change from s o i l to s o i l . These changes have also been observed to be affected by a number of complex fac tors . Tota l S o i l Manganese: Tota l manganese has usual ly been determined by ac id ex t rac t ion using a ternary d iges t ion mixture of HNO^, H^SO^ and HCIO^. In 1947, Leeper working. in A u s t r a l i a observed a range of t o t a l manganese i n s o i l from 0.1% to a few parts per m i l l i o n . Robinson (1929) reported a range i n t o t a l manganese from 0% to 0.31% as manganese oxide i n the United States. S o i l s with up to 10.0% manganese oxide have been reported from Hawaii (Bear, 1946). Btaker (1950) found t o t a l manganese i n some B r i t i s h Columbia s o i l s to range from 0.007 to o.494%. Climate has been found to have a pronounced effect upon the t o t a l manganese content of s o i l . I t s effect i s c h i e f l y i nd i r ec t through i t s influence on s o i l reac t ion (Leeper, 1947; Fujimoto and Sherman, 1945). In a r i d regions basic ions accumulate. However, under humid condit ions su f f i c i en t p r e c i p i t a t i o n f a l l s to leach most of the s o i l bases which r e su l t i n s o i l a c i d i t y . Considering climate only one would expect s o i l s of a r i d regions to be supplied wi th greater quant i t ies of manganese than s o i l s of humid regions. The d i s t r i b u t i o n of t o t a l manganese i n the s o i l i s c lose ly re la ted to the processes of s o i l formation. According to Leeper (1947) eight factors influence the d i s t r i b u t i o n of t o t a l manganese i n the s o i l p r o f i l e . These are: - 9 -1) The weathering of minerals or dead plants to l i be ra t e manganous ions; 2+ 2) downward movement of Mn i n drainage water; 2+ 3) equi l ibr ium between Mn i n so lu t ion and as exchangeable ca t ion attached to negative s o i l c o l l o i d a l complex; 2+ . . . . . . 4) uptake of Mn by roots , followed by i t s return i n l i t t e r to the surface; 2+ 5) oxidat ion of Mn to higher oxides by oxygen or bac te r ia ; 6) aging of manganic oxides from highly reac t ive to less reac t ive or iner t forms; 2+ 7) reduction of manganic oxide to Mn by organic matter or b a c t e r i a l ac t ion ; 8) d i r ec t absorption of manganic oxides by plants or s o i l microorganisms. Leeper states that the f i r s t four factors are common to other metals, but the l a s t four are spec i f i c for manganese. On the basis of these eight factors Leeper suggests four common types of manganese d i s t r i -bution i n a p r o f i l e : -a) Surface accumulation with minimum i n sub-surface, then gradual increase with depth. Leached s o i l s show th is pat tern. The concentration at the surface i s a t t r ibu ted to plant ac t ion ; - 10 -b) Steady decrease with depth. This i s found i n leached s o i l s , e spec ia l ly those with red tones; c) Steady manganese values throughout the p r o f i l e . This i s cha rac t e r i s t i c of pedocals and unleached s o i l s ; d) Accumulation i n the subso i l jus t above the calcareous l aye r . Higher Oxides of Manganese The higher oxides of manganese i n s o i l deserve more de ta i l ed a t ten t ion since a l l but a minute f r ac t ion of the manganese i n neutra l and s l i g h t l y a l k a l i n e s o i l s i s converted to th i s form (Leeper, 1947). The degree of r e a c t i v i t y of these higher oxides was thoroughly studied by D'Agostino (1938). He studied these d i f ferent forms of MnO^, both na tura l and synthetic i n order to estimate the i r value as depolar izers i n dry c e l l s . A modif icat ion of D'Agost ino 's method leads to the extrac-t i on of the most reac t ive manganic oxide from a s o i l by a short treatment with a gentle reagent, such as a cold neutral so lu t ion of hydroquinone. The same s o i l may also contain iner t oxides which w i l l not d i sso lve w i th in a reasonable time unless treated wi th hot strong acid plus a reducing agent. Poss ib ly the iner t form might react with the gentler reagent i f i t could be given enough time; but the rate of react ion i s the essen t ia l point here (Leeper, 1947). - 11 -Highly Reactive Manganic Oxide: The existence i n some s o i l s of a h ighly react ive form of manganic oxide which i s reduced by hydroquinone wi th in 15 seconds, l i b e r a t i n g a lka l i ne MnCOH)^ has been known for many years. This highly react ive form can be estimated by extract ing the s o i l wi th hydroquinone i n a neutra l so lu t ion of ammonium acetate or some other s a l t (Leeper, 1947). Gis iger (1935) found that a three-minute period was su f f i c i en t to extract these h ighly reac t ive forms of manganic oxides from the s o i l . He pointed out that longer periods of ext rac t ion such as the 7 hours o r i g i n a l l y suggested (Leeper, 1935) al low less react ive manganic oxides to d isso lve and so obscure the contrast between these and the most ac t ive forms. McCool (1934) suggested another method of estimating th i s f r ac t ion of s o i l manganese which i s used on h ighly acid s o i l s . In th i s procedure, the dry s o i l under study i s stored for a period of a month at a temperature o of 72 F or higher and then extracted with water. This treatment was found p a r t i c u l a r l y useful on highly ac id s o i l s which may accumulate tox ic amounts of manganese by the in t e rac t ion of organic matter and manganese oxides. McCool found that the method d id not apply where microb ia l ox ida t ion was appreciable or i n moderately ac id s o i l s , where water soluble manganese decreased with time of storage. This h ighly react ive form has been detected q u a l i t a t i v e l y by other methods (Dion and Mann, 1946, and Robinson, 1929). - 12 -Less Act ive Manganic Oxides The less ac t ive forms of manganic oxide, i s defined as that which reacts with hyposulf i te at pH 7; but not with hydroquinone (Leeper, 1947). Generally manganic oxide, whatever c l a s s , becomes more susceptible to attack by common reducing agents as the pH f a l l s . Thus, a moderately ac t ive f r ac t ion might be defined as that d issolved by hydroquinone i n 0.05 N I^SO^, but not at pH 7. This f r ac t ion overlaps the less ac t ive form jus t mentioned above. The rest of the manganic oxide, which requires more d ras t i c treatment for i t s so lu t ion , may be regarded as i n e r t . Exchangeable manganese: Exchangeable manganese i s that f r ac t ion held i n a replaceable form by s o i l c o l l o i d s . Some people have included i n th i s f r ac t ion the manganese present i n s o i l s o l u t i o n . Ext rac t ion of the s o i l wi th neutra l normal ammonium acetate so lu t ion gives one measure of exchangeable manganese; but some other extractants , for example, 0.5 M Mg(N0 3 ) 2 (Steenbjerg, 1935) or 0.5 M Ca(N0 3 ) 2 (Heintze, 1938) bring more manganese into s o l u t i o n . D i lu t e acids have sometimes been used as reagents for exchangeable manganese but Leeper (1947) con-sidered th i s as an unsound p rac t i ce , since an acid also d issolves some higher oxides. Leeper (1947) considered that the term "exchangeable manganese" has l i t t l e meaning unless the nature of the replacing ion i s defined. I t i s thus better to use the term "extractable manganese" and to define the extract ing so lu t i on . A further d i s t i n c t i o n should be made - 13 -of whether the s o i l i s moist or a i r - d r i e d , since several workers have observed that i n a i r - d r i e d s o i l s both exchangeable and ac id-so luble manganese are present i n greater amounts than i n the moist s o i l s (Fujimoto and Sherman, 1945; Sanchez and Kamprath, 1959). Organic forms of Manganese: Serdobolski i and Sinyagina (1953) have demonstrated that man-ganese may also migrate i n s o i l s i n the form of metallo-organic complexes. These authors give examples of compounds of manganese with c i t r i c , t a r t a r i c , oxa l i c and humic ac ids . i i ) Effects of pH, Organic Matter and Moisture on S o i l Mn The status of manganese i n the s o i l i s governed by pH, organic matter, moisture and temperature. The effects of these factors are general ly ref lec ted through the i r influence on the redox po ten t i a l and the hydration-dehydration of the manganese compounds (Fujimoto and Sherman, 1948). An understanding-of the influence of one factor on manganese status i s more complete when other factors are considered simultaneously. In 1923 McHargue observed that manganese added without lime was toxic to p lan ts , but the same amount of manganese increased y i e ld s when added af ter l i m i n g . This i s often quoted i n discussions on importance of pH to micronutrient a v a i l a b i l i t y . Generally s o i l s with pH values lower than 5.5 contain a larger amount of the i r manganese i n the bivalent form, that i s water-soluble and 2+ exchangeable; with increasing pH Mn w i l l be oxidized into manganic oxides 3-f" 4*f* (Mn and Mn ) (Leeper, 1947). This resu l t s i n a decrease of the form - 14 -ava i l ab le to p lants . This conversion presumably depends l a rge ly ei ther d i r e c t l y or i n d i r e c t l y on the a c t i v i t y of microorganisms. The oxidat ion 2+ of Mn which i n the test tube takes place at pH values above 8, proceeds i n the s o i l at much lower values probably owing to the presence of hydroxy acids and perhaps pyrophosphate (Sohngen, 1914; Heintze and Mann, 1947a; Mulder and Gerretsen, 1952). However, Mattson et a l . , (1948) were 2+ unable to observe a s t imulat ing effect of hydroxy acids on Mn ox ida t ion . F i x a t i o n of added manganese i n a non-exchangeable form i n many neutra l or a l k a l i n e s o i l s proceeds r a p i d l y . Wain et a l . , (1943) and Sherman and Harmer (1942) have observed f i x a t i o n of added manganese w i th -i n a few days after i t s app l i c a t i on . Heintze (1946) observed that the exchangeable manganese content of a s o i l can f a l l r ap id ly after l i m i n g . He added increasing amounts of lime to a c lay loam and determined the pH values and exchangeable manganese contents after one week's incubation. Increasing the amount of lime from 0 to 12 tons per acre, increased the pH from 4.5 to 7.9, but decreased the exchangeable manganese content from 10.2 to 2.0 mg.%. However, i n some studies heavy appl ica t ions of lime i n the form of CaO to manganese def ic ien t s o i l s have been found to be b e n e f i c i a l (Maschaupt, 1934; Popp e t " a l . , 1934; Gis iger and Hasler , 1948). At high pH values s o i l organic matter apparently may reduce higher manganic 2+ oxides to Mn (Mattson et a l . , 1948). The ease with which MnO^ accepts hydrogen from a va r i e ty of reducing agents inc luding mic rob io log ica l systems was demonstrated by Mann and Quastel (1946). An important cont r ibut ion to our knowledge of - 15 -the d i f ferent states i n which manganese may be present i n the s o i l comes from Dion and Mann (1946). Of perhaps greater s igni f icance i s the a t tent ion these authors c a l l to the presence of t r i v a l e n t manganese i n 3+ 2+ s o i l s and the fact that Mn i s known to dismutate spontaneously to Mn 4+ and Mn . From these considerat ions, the authors were led to postulate a manganese cycle i n s o i l i n which Mn02 i s formed through the b i o l o g i c a l 2+ 3+ oxidat ion of Mn to Mn with subsequent dismutation of the l a t t e r , and 2+ i s reduced d i r e c t l y to Mn by b i o l o g i c a l reduct ion. They represented the cycle as: Autoxidat ion Exchangeable Mn (Mn++) V A MnO, (Mn++++) Reduction Dismutation Mn 2 0 3 . xH 2 0 (Mn+++) To show the effect of pH on th is process they car r ied out an 2+ experiment to measure the amount of Mn produced i n one week as a resu l t of storage of Mn(0H).j at d i f ferent pH values. At pH 7.5, 10.7% dismuta-t i o n was observed after one week, whereas at pH 6.18 a value of 82% was found. The resu l t s of Mattsori et a l . , (1948) confirm the concept of Dion and Mann as to the occurrence i n a lka l ine s o i l s of a large part of the - 16 -s o i l manganese i n the t r i v a l e n t s t a t e . The r o l e of organic matter and r e l a t e d m i c r o b i a l a c t i v i t y i n 2+ the oxidation of Mn to insolu b l e manganic compounds i n the s o i l i s not c l e a r . The e f f e c t of organic matter may be due to the presence of hydroxy acids which according to Sohngen (1914) and Heintze and Mann (1947b) play an important part i n the transformation of s o i l manganese. Heintze and Mann (1949b) advanced the hypothesis that manganese d e f i c i e n c y of plants on ne u t r a l and a l k a l i n e s o i l s high i n organic matter content and of adequate t o t a l manganese content i s due to the formation 2+ of complexes of Mn with the organic matter which are d i s s o c i a t e d only to such a s l i g h t extent that the a v a i l a b l e manganese i n the s o i l i s i n s u f f i c i e n t f o r the needs of the plants. These authors observed the formation of such complexes but Jones and Leeper (1951), found no evidence f o r the existence of such complexes i n t h e i r experiments. Main and Schmidt (1935) suggested that manganese may form chelate complexes with ot-hydroxy acids and d i c a r b o x y l i c a c i d s . Mellor and Malley (1948) have arranged the t r a n s i t i o n elements i n order of s t a b i l i t y of t h e i r chelate complexes. In the se r i e s which they prepared, the value of the logarithm of the s t a b i l i t y constant f o r di v a l e n t man-ganese was 6.8 as compared with a value of 13.8 f o r cupric ion, the most sta b l e complexing ion. - 17 -Heintze and Mann (1947b, 1949a) found that the addi t ion of ce r t a in inorganic sa l t s to normal ammonium acetate extracted more man-ganese than did ammonium acetate alone. CuSO^ was found to be most e f f i c i e n t followed by C o C ^ and Z n C ^ . The chela t ion concept and the resu l t s of Main and Schmidt and Mel lor and Malley offer an explanation for the observations made by Heintze and Mann on the e f f i c iency of CuSO^ as a manganese extractant from organic matter. Since copper forms a more stable chelate complex than does manganese, copper probably would replace manganese i n the chelate complex by a type of "exchange" and the manganese could be removed from the s o i l by ex t rac t ion . Hemstock and Low (1953) supported the view of Heintze and Mann and considered manganese to be held i n an organic complex. Page (1962) makes a further suggestion that the formation of complexes i s cont ro l led by pH; at higher pH, the p robab i l i t y of complex formation i s increased. He observed also that complexes might be formed by the phenolic f r ac t ion of the organic matter. Trocme and Barbier (1950) observed that with an increase i n humic acid content of the s o i l , exchangeable manganese shows an increase. Christensen, Toth and Bear (1950) showed that addi t ion of sugar increased exchangeable manganese. Passioura and Leeper (1963) put for th an X-hypothesis- that there are substances X present i n the organic f rac t ion of s o i l which hold - 18 -b ivalent manganese i n an unexchangeable form as a covalent complex MnX. This i s a double hypothesis: (a) that such a complex comprises a major f rac t ion of the bivalent manganese, (b) that t h i s f r ac t ion i s unavailable to p lan ts . Arguments for and against the X-hypothesis are given and using synthetic systems i n which manganese and calcium are competi t ively adsorbed on organic c o l l o i d s , the authors reject the hypothesis that important amounts of manganese unite i n non-exchangeable form with the s o i l organic matter. Very recent ly Misra and Mishra (1969) working i n India have come to the conclusion that organic matter i s c lose ly associated with the re tent ion of manganese i n an exchangeable form. They found that the des t ruct ion of organic matter or i t s addi t ion decrease or increase the -exchangeable form of manganese respec t ive ly . Christensen, Toth and Bear (1950) invest igated changes i n applied manganese as influenced by s o i l moisture, pH and organic matter. They concluded that, with other factors held constant, the exchangeable manganese decreased as the moisture content increased to f i e l d moisture capaci ty . This effect of moisture was due to the increased rate of organic matter decomposition associated - with the higher moisture l e v e l s . I I I . . Soil-Plant-Manganese Relat ionships i ) Manganese a v a i l a b i l i t y and i t s estimation by chemical  ana lys i s : Recent developments i n the chemistry and a v a i l a b i l i t y of micro-- 19 -nutr ients are d i f f i c u l t to generalize because of the great d i v e r s i t y of the chemical properties of these micronutr ients , the i r reactions with s o i l , and the plant roo t ' s a b i l i t y to absorb them from the s o i l . Manganese i s no exception to th i s observation since i t s a v a i l a b i l i t y to plants i s known to be re la ted to the chemistry of manganese i n the s o i l . I t i s essen t ia l to d i s t i ngu i sh between t o t a l manganese content of a s o i l and plant ava i lab le manganese. Total content of manganese i n s o i l has l i t t l e connection with the a b i l i t y of the s o i l to supply manganese to p lan ts , and may be considered as of secondary importance for plant growth. In 1935, Leeper maintained that the supply of manganous manganese i s not always a good c r i t e r i o n of ava i l ab le manganese as some s o i l s cannot maintain a sa t i s fac tory l e v e l of th i s form. His work showed that, a measure-ment of manganese wi th in the manganous-manganic equi l ibr ium i n the s o i l i s a more r e l i a b l e i nd i ca t i on of the capacity of the s o i l to provide the plant with the required manganese. He hypothesized the existance of s o i l manganese i n a dynamic equi l ibr ium i n which the f i r s t three members of t h i s equi l ibr ium represent the ava i lab le or "act ive manganese" as i t i s c a l l e d by Leeper (1935, 1947). This "act ive manganese" thus includes 2 water-soluble and exchangeable Mn + and those forms of manganic oxide which are ea s i l y reducible by hydroquinone at pH 7. Several workers (Jones and Leeper, 1951; Heintze, 1956) have since shown that higher oxides of manganese are po ten t i a l sources of ava i l ab le manganese and that the i r a v a i l a b i l i t i e s i n some cases are correla ted with the i r r e d u c i b i l i t i e s by hydroquinone. - 20 -The general consensus of opinion i s that plants take up d ivalent manganese from the s o i l so lu t ion (Leeper, 1947; Fujimoto and Sherman, 1948; Weir and M i l l e r , 1962), although there i s also the p robab i l i t y that soluble anionic complexes of manganese are ava i lab le to plants (Heintze, 1957). Thus the replenishment of t h i s supply from other forms through an equi l ibr ium cycle i s e ssen t i a l for normal plant growth. The rate of conversion from one form to another i s of greater importance than the absolute amount i n any one form since the t o t a l amount of manganese i n the cycle i s large i n r e l a t i o n to plant requi re -ments. Several cycles have been proposed by which divalent manganese i n the s o i l so lu t ion or on the exchange complex i s transformed to less ava i l ab le forms and l a t e r released again for plant use. There i s , however, no general agreement among s o i l s c i e n t i s t s on the components of the equi l ibr ium c y c l e . Information on rates of exchange between the various forms i s also almost e n t i r e l y lack ing i n the l i t e r a t u r e . This i s due i n part to the absence of sui table techniques to measure the rate and amount of transfer from one form to another. Various methods have been used for the determination of the manganese f rac t ion i n the s o i l which i s ava i lab le to p lan ts . Attempts have been made to determine the manganese pa r t ly as an exchangeable f rac -t i o n by ext rac t ion with a neutra l e l ec t ro ly t e and pa r t l y as a reducible f r ac t ion by treatment of the s o i l with a reducing agent. - 21 -Dion, Mann and Heintze (1947) invest igated the factors c o n t r o l l i n g the r e d u c i b i l i t y of higher manganese oxides. Estimation of the ea s i l y reducible manganese appeared to be dependent on the pH of the system, the nature of the s a l t so lu t ion , the nature of the reduc-ing agent, the time of contact i n addi t ion to the amount and nature of the higher oxides of manganese present. Pyro lus i t e (MnO^) and a synthetic preparation of MnCOH)^ were found to be ea s i l y reducib le . Manganite [MnO(OH)] and hausmannite (Mn M^O^) are apparently only reduced with d i f f i c u l t y . In 1954, Finck working on gray speck disease i n oats compared eight methods for estimating plant ava i lab le s o i l manganese. Only those methods that provided.an estimate of e a s i l y reducible manganese were of any value i n d i f f e r e n t i a t i n g between manganese def ic ien t and non-deficient s o i l s . He also concluded that the pH value of the s o i l s with which he was working was a better c r i t e r i a for p red ic t ing the probable development of gray speck disease. Very recent ly Browman ji t al_. (1970) evaluated the a v a i l a b i l i t y of s o i l manganese to corn i n r e l a t i o n to e x t r a c t a b i l i t y of s o i l manganese by EDTA, Mg(N0 3 ) 2 > CH^OONH^,, hydroquinone, ^ P O ^ and NH 4 H 2 P0 4 as affected by l iming under f i e l d conditions on a s ingle s o i l type. They found an inverse r e l a t i o n between EDTA, Mg(N0 3 ) 2 and CH^COONH^ - extractable man-ganese and ava i lab le manganese. No useful re la t ionsh ips were found between hydroquinone, H^PO^ and NH^H^O^ - extractable s o i l manganese and manganese uptake by sweet corn. - 22 -In a Report of a meeting on s o i l a c i d i t y and l iming at the Research Sta t ion , Beaverlodge, Alber ta i n 1969 a suggestion i s made that shaking a s o i l at a 1:2 r a t i o with 0.02 M CaCl^ so lu t ion for one hour could be used for extract ing aluminum and manganese from acid s o i l s i n order to predict the i r damage to f i e l d crops. The effects of synergism and antagonism between manganese and other nutr ient elements must be considered when looking for chemical methods that determine manganese a v a i l a b i l i t y to plants (Martin e_t aJL., 1953 and H i l l et a l . , 1953). Two reasons for the u n a v a i l a b i l i t y of manganese to oats and other sens i t ive plants growing on sandy and peaty s o i l s i n the pH range of 6.5 - 8.0 were given by Passioura and Leeper (1963) when they discussed manganese a v a i l a b i l i t y and the X-hypothesis. F i r s t , that p r a c t i c a l l y a l l the manganese has been b i o l o g i c a l l y oxidized to the higher insoluble oxides ( c o l l e c t i v e l y denoted as MnO£). Secondly, that the manganese re ta ins i t s valence of two but i s held i n such a strong covalent l i n k by organic c o l l o i d s that the root cannot obtain i t s necessary supply. The authors considered these two reasons to be i n c o n f l i c t for the reason that i f the manganese i s so t i g h t l y bound as to be beyond the reach of roots , i t should also be beyond the reach of bac te r i a , and so should remain b iva l en t . According to Fujimoto and Sherman (1948) two processes i n the s o i l influence manganese a v a i l a b i l i t y to p lants . F i r s t , the ox ida t ion-reduct ion, and secondly, the hydration-dehydration process of the manganese - 23 -oxide. The oxidat ion-reduct ion system determines the r e l a t i v e amounts of manganous oxide and manganese dioxide as i l l u s t r a t e d i n Figure 1. When free manganous oxide, manganese d iox ide , and water are present i n the s o i l , add i t ion and hydration of the oxides w i l l take place with the formation of a complex hydrated manganese oxide, as shown i n the lower por t ion of Figure 1. This form of oxide i s thought to be stable when moisture i s present and the temperature i s low. MnO reduction (MnO) (MnO ) (H„0) x Z y z z Dehydration I y MnO^ - 2 1 x MnO, z H 20 Figure 1. The Manganese cycle i n s o i l . (After Fujimoto and Sherman, 1948) - 24 -When the s o i l becomes dry and the s o i l temperature r i s e s , t h i s form of oxide breaks up into i t s component par ts . The components can then come under the influence of e i ther one of the two processes ( i . e . oxidat ion-reduct ion or hydration-dehydration), or one of the components may be taken up by p lan ts . i i ) Deficiency and T o x i c i t y Levels : There i s l i t t l e agreement i n the l i t e r a t u r e as to the c r i t i c a l amount of manganese i n plants below which def iciency symptoms may be found. Samuel and Piper (1929), Piper (1931) and Leeper (1935) found 14 to 15 ppm i n the whole plant at the flowering stage to be the lowest value i n healthy cerea ls . Hasler (1951) found the fol lowing concentrations of manganese i n manganese-deficient grasses: Arrhenatherum e la t ius L . , 37 ppm; Festuca pratensis Huds., 44 ppm. A large v a r i a t i o n i n the manganese content of various grass species grown on the same s o i l has been recorded by Beeson et^  al_. , (1947). Under the condit ions of the i r experiments, Agrost is alba L . contained 815 ppm manganese, whereas Poa pratensis L . had values of 108 and 164 ppm. Seekles (1950) determined manganese contents of grass grown on di f ferent s o i l s i n the Netherlands. Grass from c lay s o i l s had the lowest manganese content of 114 ppm i n the dry matter; that from peaty s o i l s had 152 ppm and that from sandy s o i l s 191 ppm. Steenbjerg (1935), working on the s o i l s of Denmark, set the l i m i t between "healthy and s i ck" s o i l s with respect to ava i l ab le manganese at 2 to 3 ppm. This range was quite sa t i s fac tory to Steenbjerg but others - 25 -have reported " s i ck" s o i l s containing more than th i s minimum and "healthy" s o i l s with less than 1 ppm (Sherman, McHargue and Hodgkiss, 1942; Heintze, 1946). Sherman (1950), studying the s o i l s of Hawaii concluded that manganese def ic ienc ies i n plants were not necessar i ly re la ted to the l e v e l of manganese i n the s o i l , or the l e v e l of manganese uptake by the p lan t . He considered the r a t i o of i ron to manganese to be more important since plants could be c h l o r o t i c wi th 500 ppm manganese i f the i r o n -manganese r a t i o was not sa t i s fac to ry . From the resu l t s of several inves t iga t ions i t appears that manganese t o x i c i t y i s one of the main causes of s o i l a c i d i t y in jury to p lan ts . Ke l l ey (1909) indicated the re la t ionsh ip between the poor growth of pineapple i n the d r i e r regions of the Hawaiian Islands and the high manganese content (1 to 4%) of the s o i l s . Extensive pot experiments wi th s i m i l a r s o i l s have been car r ied out i n Puerto Rico by Hopkins et_ a l . , (1944). Lohnis (1946, 1951) concluded from the manganese contents of the various plants tested for manganese t o x i c i t y that a tolerance for a high l e v e l of ava i l ab le manganese i n the s o i l may be due (1) to a weak absorption of manganese (oats, mustard, mangold) and (2) to a strong tolerance w i th in plants (tobacco, f l a x , strawberry, potato and presumably broad bean). S t r i k i n g examples were found to be oats, which contained only 325 ppm of manganese when growing on an acid s o i l , and tobacco, which - 26 -contained nearly 3,000 ppm. Both plant species showed no v i s u a l symptoms of manganese t o x i c i t y . Jacobson and Swanback (1932) recorded values of 5,250, 6,470 and 11,670 ppm of manganese i n tobacco suffer ing from Mn t o x i c i t y . This review of l i t e r a t u r e leads to the conclusion that as more i s known about the chemistry and behaviour of s o i l and plant manganese, simple general izat ions about them w i l l become progressively less accept-able. This further emphasises the need for a study of the Mn status and the re la ted factors of the Lower Fraser Va l l ey s o i l s . MATERIALS AND METHODS Samples The s i x s o i l s used i n th i s study were a l l from the Lower Fraser Val ley i n the Province of B r i t i s h Columbia. Three of the samples, representing G r e v e l l , Hazelwood and Monroe se r ies , were derived from A l l u v i a l parent ma te r i a l . The others, representing Cloverdale, Milner and Sunshine series were from Marine deposi ts . Some phys ica l and chemical properties of these s o i l s are summarized i n Tables 1(a) and K b ) . A l l samples were a i r - d r i e d , crushed with a wooden r o l l e r , and passed through a 2-mm s ieve . The sieved samples were stored i n card-board boxes. Chemical Analys is S o i l pH was determined with a Corning Model 12 pH meter using a s o i l : water r a t i o of 1:2.5 and a s o i l : 0.02 M CaCl^ so lu t ion r a t i o of 1:2 (Jackson, 1958. Modified only with respect to the concentration of the CaCl^ s o lu t i on ) . Tota l carbon content was determined by the dry combustion method using the Leco Induction furnace and Carbon analyser, model 572-200 (Laboratory Equipment Corporation, St . Joseph, Michigan) . Samples of 0.25 - 0.50 grams, depending on the carbon content, were mixed with one scoop (approximately 0.8gm) each of i ron and t i n accelerator (Black, 1965). .- 28 -Cation exchange capacity (C .E .C. ) was determined by the ammonium acetate (pH 7.0) and the sodium acetate (pH 8.2) methods (Black, 1965). In the sodium acetate method, Na"*" was determined using atomic absorption spectrophotometry. Determination of manganese i n ext rac ts : The s o i l extracts were aspirated d i r e c t l y into a Model 303 Perkin-Elmer atomic absorption spectrophotometer, with a manganese hollow-cathode lamp and the fo l low-o ing operating condi t ions : wavelength 279.8 m u , 7 A bandpass, lamp current 25 mA, and a i r and acetylene pressures/flow rates of 30/5.5 and 8/5.5 (Perkin-Elmer 303 Burner Regulator uni t s ) r e spec t ive ly . Manganese Ext rac t ion Procedures Ext rac t ion condit ions were standardized according to the method of Heintze (1938). A l l ex t rac t ions , wi th the exception of t o t a l manganese, were effected by the ag i t a t ion of s o i l and extractant i n 100 ml centrifuge tubes on a mechanical shaker for one hour at a s o i l : so lu t ion r a t i o of 1:10. The suspensions were centrifuged at 2,500 r .p .m. for 15 minutes using an In ternat ional No. 2 centrifuge and f i l t e r e d using Whatman No. 42 f i l t e r paper. Each sample was extracted successively for water so luble , exchangeable and ea s i l y reducible manganese with d i s t i l l e d water, followed by 1 N NH^OAc (pH 7.0) and followed by a 0.2% so lu t ion of hydroquinone i n IN NH OAc (pH 7.0) r e spec t ive ly . - 29 -Manganese extract ions were also made with 0.02 M solut ions of Disodium Ethylenediamine-tetracetate (EDTA) and C a C l ^ The EDTA ext rac t ion was car r ied out i n two ways. In one method the samples were d i r e c t l y extracted with the EDTA so lu t ion . In the second method, the samples were f i r s t extracted with IN NH^OAc (pH 7.0) containing 0.2% hydroquinone and then with the EDTA so lu t ion . Ext rac t ion of Tota l S o i l Manganese: Tota l manganese was determined by atomic absorption spectrophotometry after ext rac t ion wi th perch lor ic acid according to the procedure of Jackson (1958). The method involved a prel iminary predigest ion of s o i l with concentrated HNO^ for 30 minutes at 180°C. The s o i l was then subjected to a second d iges t ion with a ternary mixture of HNO^, l^SO^ a n c * HCIO^ i n the r a t i o of 1 0 : 1 : 4 . The second diges t ion was done i n a perchlor ic acid fume hood at 180-200°C u n t i l so lu t ion cleared (approximately one hour). The so lu t ion was cooled, f i l t e r e d and subsequent d i l u t i o n s made where necessary before the manganese determination. Manganese i n vegetat ion: Some ex i s t i ng vegetation at three of the s i x sample s i t e s were co l lec ted for a comparative study between the s o i l "act ive manganese" and the t o t a l manganese content i n the vegetat ion. Water soluble and t o t a l manganese i n the vegetation were extracted and determined using the methods described above. - 30 -P a r t i c l e s ize separation: S o i l p a r t i c l e separation was achieved by dispers ion i n d i s t i l l e d water. A mixture of 5g s o i l and 50ml d i s t i l l e d water i n 100ml centrifuge tubes was subjected to u l t r a -sonic v i b r a t i o n for 30 minutes (Edwards and Bremner, 1967) using DisOntegrator Ul t rasonic Cleaner (Ultrasonic Industries Inc. N . Y . ) with system No. 40, Generator Model No. G-40 C l - P , a frequency of 80kcs. , and 80 watts power output. The mixture was centrifuged for three minutes at 2500 r .p .m. using an Internat ional No. 2 centrifuge and the suspension decanted into a large beaker. Dispersion and centr i fugat ion was continued u n t i l the suspension became c l ea r . The residues from the centrifuge tubes (>2u) were a i r - d r i e d and analyzed for manganese f rac t ions . The suspensions (<2y) were subjected to high speed cent r i fugat ion . The c lear supernatant so lu t ion was analyzed d i r e c t l y for manganese and the residue was freeze dried and analyzed for various manganese f rac t ions . S t a t i s t i c a l analyses: S t a t i s t i c a l analyses employed i n the study involved the IBM 360/7 computer and the INMSDC, SIMREG, T-TEST and STPREG routines of the Triangular Regression Package (TRIP) program stored i n the program l i b r a r y at the Univers i ty of B r i t i s h Columbia Computing Centre (Bjerr ing e_t a l . , 1968). - 31 -RESULTS AND DISCUSSION D i s t r i b u t i o n of the forms of s o i l manganese The d i s t r i b u t i o n of manganese fract ions i n a l l the s o i l samples i s given i n Table I I . Water soluble Mn ranged from 0.5 to 1.4 ppm; Exchangeable from 0.5 to 15.0 ppm; Hydroquinone reducible from 0.7 to 119.5 ppm; Tota l Mn from 82.0 to 957.5 ppm; and "Act ive Mn' from 3.2 to 129.8 ppm. The ranges for water-soluble, exchangeable and reducible forms of Mn are s imi l a r to those reported for various s o i l s i n other parts of Canada (Reid and Webster, 1969) and the United States (Sherman et a l , 1942). The range for t o t a l Mn i s s i m i l a r to reported values i n some Danish s o i l s (Boken, 1958), but i s lower than the resu l t s of Baker (1950) on s o i l s from the same area. Baker recorded values up to 4000 ppm of t o t a l Mn for some s o i l s . On the basis of o r i g i n some of the s o i l s studied were comparable with Baker's and hence these discrepancies may be due to differences i n a n a l y t i c a l or sampling methods. The t o t a l range for water soluble Mn was very narrow. General-l y there was r e l a t i v e l y l i t t l e v a r i a t i o n i n water soluble content between s o i l s and wi th in p r o f i l e s (Table I I ) . For example, i n the Cloverdale p r o f i l e with a range of 0.9 to 1.1 ppm, there was a f a i r l y even d i s t r i b u -t i o n ; but even though not s i g n i f i c a n t , Monroe and Milner p r o f i l e s show s l i g h t decrease and increase with depth respec t ive ly . TABLE 1(a). Some Physical and Chemical Properties of the S o i l s Derived from A l l u v i a l Deposits Order Subgroup Series Regosol Orthic G r e v e l l Gleysol Orthic Hazelwood Humic Brunisol Orthic Monroe Eu t r i c (Degraded Eutric) Depth pH Horizon (inches) (water L-H 3 - 0 — 0- 9 5.19 9-11 5.21 C l j . 11-36 5.26 HCg . 36-39 6.57 C 3 39+ 6.23 Ap 0- 8 5.15 AB 8-11 -Btg, 11-19 5.26 BtgJ 19-25 5.57 CH 25-32 5.83 C4 32-46 5.61 46+ 5.56 Ap 0-10 5.61 C 10-17 5-81 c u e 17-21- 5.70 IIC 21-28 5.76 28-34 5.91 IIC^ 34-40 5.72 n e ; 40+ 5.88 Organic CEC CEC Matter by N H 4 by Na (%) meq/lOOg meq/lOOg 0.78 2.9 6.1 0.26 2.6 4.6 0.39 2.4 4.7 1.88 15.8 16.5 0.06 3.6 5.4 11.56 42.5 40.4 5.26 . 38.5 37.3 4.68 46.1 29.3 0.65 25.3 21.5 0.39 17.8 19.9 0.52 12.2 13.7 4.39 24.4 23.5 2.71 24.3 22.6 1.55 19.9 26.5 0.58 14.2 14.1 0.39 13.4 14.0 0.26 8.7 11.4 0.13 10.7 13.2 TABLE 1(b). Some Phys ica l and Chemical Propert ies of the So i l s Derived from Marine Deposits Order Subgroup Series Horizon Gleysol Humic Cloverdale Ap Eluviated Aeg AB Btg Bt g 2 -BC Podzol Bisequa Milner Ah Min i Bfcc^ Humo-Ferric Bfcc BC k • Podzol Orthic Sunshine L-F Acid B f 1 Brown wooded Bf, (Mini Humo-Ferr ic ) Bf BC Cg C §2 *"" ' w cg 2 Depth (inches) pH (water) Organic Matter (%) CEC by NH4 meq/lOOg CEC by Na meq/lOOg 0-10 5.39 7.99 38.5 30.4 10-12 6.12 1.04 17.5 18.0 12-15 6.60 0.39 22.3 22.1 15-20 7.10 0.52 21.7 21.7 20-31 7.87 .0.33 30.4 25.5 31-39 8.22 0.85 30.7 22.3 39-53 8.44 0.13 28.9 20.2 53+ 8.35 0.16 23.7 20.1 0- 2 5.17 13.03 53.6 46.3 2- 8 5.12 5.08 33.4 35.5 8-18 5.19 3.65 28.0 30.4 18-25 5.05 1.04 32.5 27.7 25-37 5.25 0.78 40.5 26.6 37+ 5.56 0.26 29.6 22.3 2- 0 _ _ — — 0- 8 4.96 9.78 12.1 18.5 8-16 4.95 10.30 18.9 20.7 16-26 4.99 13.16 18.0 21.7 26-31 5.20 8.99 14.2 15.4 31-38 5.68 1.17 13.5 16.1 38+ 5.89 0.13 11.8 15.1 0 0 - 34 -S o i l Type and Horizon Greve l l Hazelwood Monroe Cloverdale Milner Sunshine C l C 2 Cgj H C g C Ap Btg B t g , cg2 Ap C c u e n e n q IICT Ap Aeg AB Btg B tg , BC C4 Ah Bfcc Bfcc, BC ' B f l B f 2 B f 3 BC CH Cgo, : I I . D i s t r i b u t i o n of S o i l Manganese (ppm) ' Soluble Exchangeable Hydroquinone Tota l Active Mn. Mn. Reducible Mn. Mn. Mn. 1.0 1.9 50.8 253.0 53.7 1.3 1.7 54.5 243.5 57.5 0.9 1.6 60.3 279.0 62.8 1.1 4.4 109.5 538.0 115.0 1.2 1.2 62.8 268.0 65.2 0.7 2.0 5.8 238.5 8.5 0.5 2.5 1.2 213.5 4.2 0.7 2.5 8.0 304.0 11.2 1.0 2.0 35.8 290.0 38.8 1.0 4.0 107.0 481.0 112.0 1.1 3.0 119.5 402.5 123.6 1.4 4.5 107.6 618.5 113.5 0.8 3.5 60.0 709.0 64.3 0.8 5.0 61.4 661.5 67.2 0.6 5.0 61.4 495.0 67.0 0.6 6.5 78.0 477.5 85.1 0.8 5.0 59.6 376.0 65.4 0.6 6.0 72.4 427.0 79.0 1.1 10.0 20.8 195.0 31.9 0.9 4.5 43.0 303.5 48.4 1.0 3.5 65.1 319.0 69.6 1.1 3.5 102.0 .475.0 106.6 1.0 0.7 93.1 472.5 94.8 1.0 0.5 72.9 489.0 74.4 0.9 2.0 90.2 491.0 93.1 1.1 1.5 90.0 545.5 92.6 0.8 15.0 114.0 957.5 129.8 0.6 2.0 25.7 505.0 28.3 0.8 3.0 13.6 413.0 17.4 1.0 3.5 7.0 501.0 11.5 0.8 3.5 15.1 . 560.0 19.4 1.2 4.0 54.6 587.0 59.8 1.1 3.5 13.7 187.0 18.3 1.0 2.5 7.5 129.5 11.0 1.1 2.0 1.4 100.0 4.5 1.0 1.5 0.7 82.0 3.2 0.9 1.5 3.4 159.5 5.8 0.7 1.0 49.5 323.0 51.2 - 35 -Exchangeable Mn showed a greater range than the water soluble form, and followed several patterns of d i s t r i b u t i o n . Within some p r o f i l e s (Cloverdale and Sunshine) there appeared to be a decrease with depth as the i r pH values increased. The Milner p r o f i l e , with 15.0 ppm of exchangeable Mn i n the Ah, 2.0 ppm i n the Bfcc^ and 4.0 ppm i n the parent mate r ia l , C^, indicated a surface accumulation, with a minimum i n the subsurface and then an increase with depth, perhaps r e f l e c t i n g the influence of pH and C . E . C . The other p r o f i l e s (Monroe, Hazelwood and Grevel l ) showed r e l a t i v e l y l i t t l e v a r i a t i o n wi th depth, except for the s l i g h t accumulation i n the f ine textured I lCg horizon of the G r e v e l l . Hydroquinone reducible Mn exhibi ted a d i f ferent d i s t r i b u t i o n pattern from the exchangeable form i n a l l the p r o f i l e s . This v a r i a t i o n was a r e su l t of the wider range of reducible Mn compared with that of exchangeable manganese. In the Greve l l p r o f i l e there was an even d i s t r i b u t i o n of the reducible Mn except for an increase i n the f ine I lCg hor izon. In the Monroe p r o f i l e the d i s t r i b u t i o n was even except for the accumulation i n the Ap hor izon. The Milner p r o f i l e showed a surface accumulation, s l i g h t decrease and then an increase with depth. The Sun-shine showed a decrease with p r o f i l e and then an increase i n the lower hor izon. In the Cloverdale p r o f i l e , reducible Mn increased gradually from 20.8 ppm i n the Ap to 102.0 ppm i n the Btg, but there was r e l a t i v e l y l i t t l e v a r i a t i o n i n the lower horizons. Hazelwood showed a minimum of - 36 -1.2 ppm i n the Btg^ horizon and a maximum of 119.5 ppm i n the bottom horizon (Cg^). There appeared to be no c lear patterns of d i s t r i b u t i o n wi th depth i n the t o t a l manganese. The Cloverdale p r o f i l e showed a gradual increase with depth i n p r o f i l e , thus f i t t i n g one of the four d i s t r i b u -t i o n categories described by Leeper (1947). In th i s p r o f i l e the surface horizons were more acid than the lower horizons. Both Milner and Sunshine showed surface accumulation, wi th a minimum i n the subsurface, then increased with depth. The two p r o f i l e s also followed one of Leeper's d i s t r i b u t i o n patterns; th i s being more pronounced i n M i l n e r , wi th 957.5 ppm i n the Ah (the highest manganese content recorded i n the study), 413.0 ppm i n Bfcc^ and 587.0 ppm i n the C^. Monroe showed an accumulation i n the subso i l (C horizon) and a decrease with depth i n p r o f i l e (from CIIC to H C ^ ) . The Greve l l p r o f i l e had a r e l a t i v e l y uniform d i s t r i b u t i o n except for the usual tendency towards accumulation i n the I lCg hor izon. There appeared to be higher concentrations of t o t a l Mn i n the lower horizons (Cg 2 and Cg^) of the Hazelwood p r o f i l e . Generally no consistent trends i n d i s t r i b u t i o n may be associated wi th these r e s u l t s . Perhaps some of these observations could be considered as patterns of d i s t r i b u t i o n other than the four main ones described by Leeper (1947). I t can be noted from Table I I that with hydroquinone reducible and t o t a l Mn, four out of the s i x p r o f i l e s show higher concentra-t ions i n the parent mater ia l than i n the surface horizons. The surface - 37 -s o i l s of these four p ro f i l e s (Greve l l , Hazelwood, Cloverdale and Sunshine) are more ac id i c and have more organic matter [Tables 1(a) and 1(b)3 than the subso i l s . These observations are in te res t ing since i n an area of high p r e c i p i t a t i o n and leaching such as the Lower Fraser Val ley one might expect considerable downward movement of manganese (Leeper, 1947, and Sherman and Harmer, 1942). Some p r o f i l e s (Cloverdale and Milner) showed higher l eve l s of exchangeable Mn i n the surface than i n the lower horizons. This was not a surpr i s ing observation because of the a c i d i c nature of these surface s o i l s which cause the reduction 2+ of higher oxides of manganese to the divalent (Mn ) form. The recovery of manganese fract ions i n terms of t o t a l Mn indicates the magnitude and e f f i c iency of spec i f i c ext rac t ion solut ions and techniques. Table I I I indicates that "act ive manganese", which includes water so luble , exchange-able and hydroquinone reducible (Leeper, 1947), makes up 2.0 to 30.7% of t o t a l Mn. The Milner and Monroe p r o f i l e s showed the highest content of t he i r "act ive manganese" i n the surface horizons, but the other p r o f i l e s had the i r highest ac t ive contents i n the lower horizons. A further examination of Table I I I reveals the amount of manganese that went in to so lu t ion when samples, wi th the i r "act ive manganese" removed, were treated wi th 0.02 M EDTA so lu t ion at pH 7.0. M i l n e r , Monroe and Sunshine p r o f i l e s had the i r highest concentrations of EDTA extractable Mn i n the surface horizons. - 38 -TABLE I I I . "Act ive" and EDTA Extractable Mn. EDTA Ext rac t -Sample Greve l l Hazelwood Monroe Milner Sunshine C l C 2 Cgj HCg C 3 Ap Btg. B tg , CH C8, Ap C cue n e net n c 3 Cloverdale Ap Aeg AB Btg 1 Btg, BC l CH Cgo Ah Bfcc Bfcc, BC 1 C, Bf B f 2 B f 3 BC eg; EDTA Ext rac t - able fol lowing :ive Mn able Mn Act ive Mn Total Mn Act ive as ppm. ppm. ppm. ppm. % of Tota l 53.7 17.5 13.0 253.0 21.2 57.5 20.0 13.5 243.5 23.6 62.8 . 32.0 14.4 279.0 22.5 115.0 90.0 72.2 538.0 21.4 65.2 28.6 16.8 268.0 24.3 8.5 6.4 15.2 238.5 3.6 4.2 4.2 3.8 213.5 2.0 11.2 18.4 19.1 304.0 3.7 38.8 36.2 20.0 290.0 13.4 112.0 122.2 61.8 481.0 23.3 123.6 135.8 51.8 402.5 30.7 113.5 42.5 88.7 618.5 18.4 64.3 10.4 60.0 709.0 9.1 67.2 7.2 54.4 661.5 10.2 67.0 6.2 40.8 495.0 13.5 85.1 6.6 43.6 477.5 17.8 65.4 5.1 29.4 376.0 17.4 79.0 5.8 35.8 427.0 18.5 31.9 40.4 41.2 195.0 16.4 48.4 57.9 45.0 303.5 15.9 69.6 64.1 55.2 319.0 21.8 106.6 115.7 83.7 475.0 22.4 94.8 97.0 73.2 472.5 20.1 74.4 64.6 67.9 489.0 15.2 93.1 43.9 78.4 491.0 19.0 92.6 61.4 98.0 545.5 17.0 129.8 59.9 227.2 957.5 13.6 28.3 52.2 46.6 505.0 5.6 17.4 3.0 26.0 413.0 4.2 11.5 3.0 6.0 501.0 2.3 19.4 2.4 14.8 560.0 3.5 59.8 8.1 40.0 587.0 10.2 18.3 5.6 34.2 187.0 9.7 11.0 4.6 23.8 129.5 8.5 4.5 1.4 2.0 100.0 4.5 3.2 0.7 0.9 82.0 3.9 5.8 2.0 3.6 159.5 3.6 51.2. 10.8 26.0 323.0 15.9 - 39 -One point of in teres t concerning the method or order of ex t rac t ion i s evident from Table III.. The data shows EDTA extractable , and EDTA extractable after removal of ac t ive or reducible Mn. EDTA extractable s o i l manganese has been used as an index of manganese a v a i l a b i l i t y to plants (Browman et a l , 1970), i n the same manner as ac t ive manganese (Leeper, 1935, 1947). A comparison of ac t ive and EDTA extractable Mn i n the Cloverdale and Hazelwood p r o f i l e s (Table I I I ) show that the d i s t r i b u t i o n of these two forms of manganese are r e l a t i v e l y the same i n both p r o f i l e s . This was perhaps an ind i ca t i on that both the EDTA extractable and ac t ive Mn represent the same chemical form of manganese. But the fact that EDTA extracted more manganese af ter the removal of the ac t ive form confuses the issue whether these two fract ions represent the same chemical form. In 24 out of 38 observations, EDTA extractable Mn was higher after the removal of reducible Mn than extract ing the s o i l d i r e c t l y with EDTA. This i s true i n nearly a l l samples with high organic matter content; thus, perhaps suggesting that the extra manganese released was held by organic c o l l o i d s . I t i s also poss ib le that the EDTA may have caused some dispers ion of the s o i l c o l l o i d s , thus re leas ing the i r manganese. D i s t r i b u t i o n of manganese between p a r t i c l e s ize separates In order to study the d i s t r i b u t i o n of manganese f ract ions i n r e l a t i o n to p a r t i c l e s i z e , selected samples were separated into f ine (<2u) and coarse (>2u) f r ac t ions . Samples were selected for t h i s part of the study on the basis of t he i r c lay and t o t a l Mn contents. Results of the - 40 -separation and manganese determinations are shown i n Tables IV to V I I . The manganese l ibera ted through dispers ion i n d i s t i l l e d water i s far higher than water soluble Mn normally determined after shaking s o i l wi th d i s t i l l e d water for one hour (Table I V ) . The mean concentrations of manganese l ibera ted through dispers ion and the normal water soluble Mn were 9.3 and 0.9 ppm respec t ive ly . A greater proportion (average of 72%) o f the t o t a l s o i l manganese occurred i n the coarse (>2]i) f r ac t ion (Table V ) . Both exchangeable and hydroquinone reducible Mn (Tables IV and VI) were f a i r l y low i n the f ine f r a c t i o n . Less of the exchangeable Mn was found i n the f ine than i n the coarse f r a c t i o n , but 60-90% of reducible Mn occurred i n the coarse f r a c t i o n . This p a r t i c l e s i ze separation and manganese analysis reveal that exchangeable Mn forms a lower proportion whereas reducible forms a subs tan t i a l ly higher f r ac t ion of t o t a l manganese. Table VII indicates that after ext rac t ing the "act ive Mn", EDTA could s t i l l extract some manganese i n both <2y and >2]i f r ac t ions , but more s i g n i f i c a n t l y i n the coarse f r a c t i o n . This again indicates the poss ible d ispers ion of the coarse f rac t ion by the EDTA so lu t i on . The most in te res t ing observation i n th i s separation and analys is was the fact that as a resu l t of the dispers ion there was a remarkable release of hydroquinone reducible Mn (Table V I ) . This and the fact that the sum of t o t a l Mn i n f ine and coarse f ract ions exceeded the t o t a l Mn i n undispersed samples (by an average of 14%) ra i se questions about the v a l i d i t y of conventional "reducible" and " t o t a l Mn" extract ions and also - 41 -TABLE IV. Water Soluble and Exchangeable Mn i n Dispersed and Undispersed S o i l Sample Cloverdale Btg, BC ' C g l Hazelwood Btg 1 Btg^ Milner Monroe C Water Normal Soluble Water Mn During Soluble Dispersion Mn (ppm) (ppm) 11.6 18.0 12.0 16.0 2.0 4.4 1.2 9.4 1.0 1.0 0.9 1.1 0.5 0.7 1.2 0.6 P .P .M. Exchangeable Mn i n S o i l Fractions <2y >2y 1.7 1.7 0.8 1.2 1.0 1.7 0.7 0.9 1.9 2.7 3.1 3.5 2.7 4.0 4.4 5.4 Tota l after Undispersed dispers ion S o i l 3.6 4.4 3.9 4.7 3.7 5.7 5.1 6.3 0.7 0.5 2.0 1.5 2.5 2.5 4.0 6.0 TABLE V. Total Mn i n Dispersed and Undispersed S o i l * Sample Cloverdale Btg, BC 1 Hazelwood Btg 1 Btg^ Milner Monroe C P . P . M . Tota l Mn i n S o i l Fract ions Total After Undispersed <2y >2y Dispersion S o i l 186 384 569 473 213 330 543 489 181 381 562 491 293 470 662 546 80 197 277 214 88 203 294 304 68 615 682 587 110 615 725 709 *A11 resu l t s after Dispersion were calcula ted as ppm of whole s o i l . TABLE V I . Hydroquinone reducible Mn i n Dispersed and Undispersed s o i l * P. P. M. MANGANESE Sample Cloverdale Hazelwood Milner Monroe Btg, BC ' C g l C g 2 Btg 1 Btg, <2y 4.8 8.5 2.9 10.5 1.6 1.4 2.3 7.4 >2y 233.1 136.8 164.7 230.8 2.5 10.6 60.8 56.4 Total after d ispers ion 237.9 145.3 167.6 241.3 4.1 12.0 63.1 63.8 Undispersed s o i l 93.1 72.9 90.2 90.0 1.2 8.0 54.6 60.0 TABLE V I I . Act ive and EDTA Extractable Mn i n Dispersed and Undispersed s o i l * P . P. M. MANGANESE Sample Cloverdale Btg, BC z cg2 Hazelwood Btg.. Btg^ Milner Monroe C Total after Undispersed <2y >2y dispers ion s o i l Act ive EDTA Act ive EDTA Act ive EDTA Act ive EDTA 18.1 7.6 246.6 91.2 264.7 98.8 94.8 73.2 28.2 13.0 157.5 38.3 185.7 51.3 74.4 67.9 15.7 6.0 179.8 51.8 195.5 57.8 93.1 78.4 27.7 19.5 250.3 53.8 278.0 73.3 92.6 98.0 4.6 0.4 7.2. 2.8 11.8 3.2 4.2 3.8 7.5 2.8 19.0 24.9 26.5 •27.7 11.2 19.1 4.2 2.7 66.4 82.4 70.6 85.1 59.8 40.0 17.7 16.0. 71.2 119.0 88.9 135.0 79.0 60.0 *A11 resu l t s after d ispers ion were ca lcula ted as ppm. of whole s o i l - 43 -about the method of d i spers ion . These observations could be due to e i ther an increased access of reagents to s o i l p a r t i c l e s , or errors introduced during the separation and ana lys i s . The main reason for using the u l t rasonic dispers ion method without any added chemical r e -agents was to minimize the a l t e r a t i on of s o i l const i tuents , e spec ia l ly the various states of manganese oxides (Edwards and Bremner, 1967). The fact that more manganese, i n whatever form, was found i n the >2y than the <2\i f r ac t ion probably indicates that the >2u f rac t ion was not w e l l dispers by the mi ld method of sonic v i b r a t i o n . While i t has often been assumed that mild d ispers ion by sonic v i b r a t i o n does not affect s o i l const i tuents , i t i s suggested that u n t i l more i s known of sonic dispers ion i t i s unwise to assume that no modif icat ion takes place. In th i s instance dispers ion . by sonic v i b r a t i o n yielded more reducible than any other f r ac t ion of manganese, but i f d ispers ion had been achieved through the use of some reducing agent, perhaps exchangeable Mn would have increased. Relat ionship Between Manganese D i s t r i b u t i o n and Parent Ma te r i a l s , pH, C . E . C . and Organic Matter Content Table I gives the pH, organic matter content and C . E . C . values for a l l the s o i l s . The pH determined i n water ranged from 4.95 to 8.44. Organic matter content was between 0.13 and 13.16%. C .E .C . determined by ammonium saturat ion at pH 7 was between 2.4 and 53.6 meq. per lOOg and 4.6 - 46.3 meq. per lOOg using the sodium saturat ion at pH 8.2. - 44 -The re la t ionsh ip between manganese d i s t r i b u t i o n (Table II) and parent mater ia ls , pH, organic matter and C .E .C . [Tables 1(a) and 1(b)] were examined by s t a t i s t i c a l techniques. A t - t es t was used i n examining the differences i n manganese d i s t r i b u t i o n due to the two types of parent mater ia ls , a l l u v i a l and marine. The fol lowing forms of man-ganese were found s i g n i f i c a n t l y d i f f e ren t : water soluble (at 5%), exchange-able (1%) and EDTA extractable after removal of "act ive Mn" (1%). Reducible, a c t ive , t o t a l , Cacl^ and EDTA extractable Mn were a l l found to be non-s ign i f i can t ly d i f ferent i n the two types of parent mater ia ls . However, due to the l imi ted number of samples used i n t h i s study, such differences need further i nves t iga t ion . A simple regression analysis was car r ied out between s o i l pH, organic matter content, and C . E . C . and water so luble , exchangeable, reducib le , t o t a l , a c t i ve , CaCl^ and EDTA extractable s o i l Mn. Results of the analysis are summarized i n Table V I I I . There were no s ign i f i can t cor re la t ions between pH or organic matter content and water so luble , exchangeable and t o t a l Mn. However, after dispersing some of the s o i l s , s i gn i f i c an t cor re la t ions were found between pH and water soluble Mn; pH and t o t a l Mn i n the <2u f r ac t ion ; organic matter content and t o t a l Mn i n both f ine and coarse f ract ions (Table V I I I ) . I f a l l cor re la t ions had been s ign i f i can t i t would have been inferred that the fac tors , pH, organic matter content and C . E . C . show a l i nea r mathematical r e la t ionsh ip with the d i s t r i b u t i o n of manganese. On the contrary, the simple regression analysis d id not lead to such a conclu-s ion . This provides evidence i n support of the observation that the TABLE V I I I . Summary of Results from Simple Regression Analys i s M a n g a n e s e F r a c t i o n s Water Exchange-Soluble able EDTA CaCl 2 EDTA after Reducible Total Act ive Soluble Soluble Act ive Water Soluble During Disper-s ion Tota l Total i n i n and f rac t ion together pH % O.M. C .E .C . C a C l 2 Soluble N. S. N. S. N. S. N. S. A A A A A N. S. N. S. N. S. N. S. A A A N. S. A N. S. A A A A N . S. A A N. S. N. S. A Ol = Signi f icant at 0.01 p robab i l i t y l e v e l S igni f icant at 0.05 p robab i l i t y l e v e l = Not s ign i f i can t - 46 -chemistry of manganese i n the s o i l i s complex; and hence most of the factors af fec t ing manganese equi l ibr ium cannot be i so la ted and discussed without due consideration of the other fac tors , since they are a l l i n t e r r e l a t ed . For example, the fact that there was a s i gn i f i can t c o r r e l a -t i on between pH and water soluble Mn; pH and t o t a l Mn i n <2u f r ac t ion ; and organic matter content and t o t a l Mn i n both f ine and coarse f ract ions (Table V I I I ) , only after dispersing the s o i l s means that s o i l texture and structure must also be considered simultaneously with the other s o i l factors i n an examination of such r e l a t ionsh ips . Exchangeable Mn was found to corre la te s i g n i f i c a n t l y (Table VII I ) + + wi th C . E . C . (determined by NH^ sa tura t ion) . In general C . E . C . by Na saturat ion at pH 8.2 was higher than that determined by NH^ + at pH 7.0 (Table I X ) . The apparent percentage of exchangeable Mn to C . E . C . was i n the range of 0.01 to 0.24% and 0.01 to 0.17% for C . E . C . determined by NH^ + and N a + methods respec t ive ly . Thus the apparent percentages (Table IX) are s i m i l a r whether the NH^ + or Na + method was used. I t i s not surpr i s ing that these percentages are so low considering the fact that manganese, as a trace element, i s only a small f r ac t ion of a l l the t o t a l cations i n the s o i l . A stepwise regression analysis was done on some of the data to f ind which of the s o i l factors (pH, organic matter content and C .E .C . ) are the best predictors of the various fract ions of s o i l Mn. The output of the computer analysis i s summarized i n Table X . C . E . C . has usual ly not been included i n discussions on s o i l factors as they affect the d i s t r i b u t i o n and a v a i l a b i l i t y of Mn, however, data here (Table X) suggest that th i s - 47 -TABLE IX. Exchangeable Mn as Apparent Percent of C . E . C . Sample Greve l l Hazelwood Monroe HCg c Ap Btg 1 Btg, CH C g 2 Ap C cue IIC I I C , ne; Cloverdale Ap Aeg AB Btg, B tg , BC cg2 Ah Bfcc Bfcc, BC 1 C, Mi lner Sunshine B f l B f 2 Bf BC C g l Cgo Exch. Mn C. E. C i by NH^"1 saturat ion (pH7) (me/lOOg) Exch. Mn as % of C .E .C . by NH/ + C . E . C . by Na+ saturat ion (pH 8.2) (me/lOOg) Exch. Mn as % of C . E . C . by Na+ 1.9 2.9 0.24 6.1 0.11 1.7 2.6 0.24 4.6 0.43 1.6 2.4 0.24 4.7 0.12 4.4 15.8 0.10 16.5 0.10 1.2 3.6 0.12 5.4 0,08 2.0 42.5 0.02 40.4 0.02 2.5 38.5 0.02 37.3 0.02 2.5 46.1 0.02 29.3 0.03 2.0 25.3 0.03 21.5 0.03 4.0 17.8 0.08 19.9 0.07 3.0 12.2 0.09 13.7 0.08 4.5 24.4 0.07 23.5 0.07 3.5 24.3 0.05 22.6 0.06 5.0 19.9 0.09 26.5 0.07 5.0 14.2 0.13 14.1 0.13 6.5 13.4 0.18 14.0 0.17 5.0 8.7 0.21 11.4 0.16 6.0 10.7 0.20 13.2 0.17 10.0 38.5 0.09 30.4 0.12 4.5 17.5 0.09 18.0 0.09 3.5 22.3 0.06 22.1 0.06 3.5 21.7 0.06 21.7 0.06 0.7 30.4 0.01 25.5 0.01 0.5 30.7 0.01 22.3 0.01 2.0 28.9 0.03 20.2 0.04 1.5 23.7 0.02 ' 20.1 0.03 15.0 53.6 0.10 46.3 0.12 2.0 33.4 0.02 35.5 0.02 3.0 28.0 0.04 30.4 0.04 3.5 32.5 0.04 27.7 0.05 3.5 40.5 0.03 26.6 0.05 4.0 29.6 0.05 22.3 0.07 3.5 12.1 0.11 18.5 0.07 2.5 18.9 0.05 20.7 0.04 2.0 18.0 0.04 21.7 0.03 1.5 14.2 0.04 15.4 0.04 1.5 13.5 0.04 16.1 0.03 1.0 11.8 0.03 15.1 0.02 TABLE X . Regression Equations of Mn Fractions on S o i l Factors and Related Data Regression Equations 100R2 (%) F -P robab i l i t y Water soluble Mn = Water soluble Mn = 0.664 + 0.062pH + 0.013 %0.M. - 0.0062 C . E . C . 1.023 + 0.0044 C .E .C . 13.12 6.84 0.1818 0.1088 N.S . N.S . Exchangeable Mn = Exchangeable Mn = 5.334 + 0.606pH + 0.052 %0.M. + 0.069 C . E . C . 1.820 + 0.074 C .E .C . 18.88 12.10 0.0645 0.0307 N.S . A Reducible Mn = Reducible Mn = = -40.99 + 17.991pH - 1.521 %0.M. - 0.330 C .E .C . = -69.78 + 20.861pH 33.03 28.14 0.0033 0.0007 A A A A Total Mn Tota l Mn = 211.53 + 11.055pH - 18.873 %0.M. + 7.978 C . E . C . = 275.97 - 20.371 %0.M. + 8.201 C . E . C . 30.69 30.47 0.0056 0.0018 A A A A Act ive Mn = Act ive Mn = = -34.99 + 17.446pH - 1.456 %0.M. - 0.268 C .E .C . = -61.607 + 20.216pH 29.02 25.26 0.0081 0.0014 A A A A C a C l 2 soluble Mn C a C l 2 soluble Mn 3.488 - 0.301pH (CaCl 2 ) + 0.145 %0.M. + 0.0047 C • E * C • 1.955 + 0.178 %0.M. 12.33 11.42 0.2079 0.0361 N.S . A EDTA soluble Mn EDTA soluble Mn 70.304 + 17.554pH - 0.559 %0.M. + 0.138 C . E . C . = -75.833 + 18.73pH 22.73 22.47 0.0304 0.0027 A A A EDTA fol lowing Act ive Mn = EDTA fol lowing Act ive Mn = = -100.26 + 20.043pH + 2.26 %0.M. + 0.863 C . E . C . = -72.9853 + 15.41pH + 1.167 C . E . C . 30.38 27.30 0.0060 0.0039 A A A A F i r s t and Second equations for each Mn f rac t ion represent the i n i t i a l and f i n a l stages respect ively of the stepwise e l iminat ion procedure; ** = s ign i f i can t at 0.01 p robab i l i t y l e v e l ; *=significant at 0.05 p robab i l i ty l e v e l ; N .S . = Not s i g n i f i c a n t . - 49 -s o i l cha rac t e r i s t i c be given more a t ten t ion . Though these resu l t s are not conclusive, there seems to be the p o s s i b i l i t y of bu i ld ing up a computer model which could predict the d i s t r i b u t i o n of s o i l Mn and perhaps i t s uptake by plants using input factors l i k e s o i l pH, organic matter content, C . E . C , texture and moisture. In view of the l im i t ed number of samples, i t might not be useful to a r r ive at mathematical re la t ionsh ips through s t a t i s t i c a l procedures, l i k e transformations of the data to f ind how pH, organic matter content and C . E . C . f i t the forms of s o i l Mn. Moreover, such re la t ionsh ips would have l i m i t e d v a l i d i t y to the understanding of the chemical and b i o l o g i c a l transformations or movements of manganese i n these s o i l s . Signif icance of the s o i l manganese d i s t r i b u t i o n i n terms of plant  requirements The pH measurements using 0.02 M CaCl^ (Table XI) ranged from 4.20 to 6.91, ind ica t ing high a c i d i t y . Under such ac id i c condi t ions , i t has been suggested that extract ing the s o i l with a 0.02 M CaCl^ so lu t ion provides a measure of plant ava i lab le Mn (Beaverlodge Report, 1969). Since th i s study does not cover the plant phase (which re la tes the s o i l Mn to plant requirements), i t i s only reasonable to predict which of these s o i l s would be def ic ien t i n plant ava i lab le manganese by a simple comparison of the various chemical methods that have been suggested elsewhere and those that have been used here. The amounts of 0.02 M C a C l 2 extractable Mn (Table XI) ranged from 0.5 to 10.7 ppm. This range i s r e l a t i v e l y wide compared with that for - 50 -TABLE X I . 0.02 M C a C l 2 Extractable Mn i n Rela t ion to other forms of Mn Sample PH S o i l : 0.02 0.02M C a C l 2 CaCl2 Extractable (1:2) Mn (ppm) . 0.02M C a C l 2 Extractable as % of Tota l Mn 0.02M C a C l 2 Extractable as % of Act ive Mn Act ive as % of Total Mn Greve l l Hazelwood Monroe Co Cgj HCg C 3 Ap Btg.. B tg , C g l cg2 Cg, Ap C cue ne nc , ne, ne; Cloverdale Ap Aeg AB Btg B tg , BC c 8 l cg2 Ah Bfcc Bfcc, BC ' C Milner Sunshine B f l B f 2 B f 3 BC eg; 5.50 2.2 0.9 4.1 21.2 5.75 3.0 1.2 5.2 23.6 5.97 2.3 0.8 3.6 22.5 5.68 3.7 0.7 3.2 21.4 5.43 3.2 1.2 4.9 ' 24.3 4.24 3.2 1.3 37.6 3.6 4.23 1.4 0.7 33.3 2.0 4.34 1.9 0.6 17.0 3.7 4.64 3.2 1.1 8.2 13.4 4.80 5.9 1.2 5.3 23.3 5.10 5.0 1.2 4.0 30.1 4.78 7.0 1.1 6.2 18.4 4.92 2.0 0.3 3.1 9.1 4.99 1.4 0.2 2.1 10.2 5.11 1.2 0.2 1.8 13.5 5.17 1.2 0.3 1.4 17.8 5.07 1.2 0.3 1.8 17.4 5.13 1.6 0.4 2.0 18.5 4.38 10.2 5.2 32.0 16.4 4.96 4.0 1.3 8.3 15.9 5.60 2.1 0.7 3.0 21.8 6.05 1.4 0.3 1.3 22.4 5.95 0.9 0.2 0.9 20.1 6.82 0.8 0.2 1.1 15.2 6.91 0.8 0.2 0.9 19.0 6.,7 6 0.9 0.2 1.0 17.0 4.78 7.2 0.8 5.5 13.6 4.58 2.1 0.4 7.4 5.6 4.66 1.6 0.4 9.2 4.2 4.20 0.8 0.2 7.0 2.3 4.21 0.7 0.1 3.6 3.5 4.66 0.8 0.1 1.3 10.2 4.57 3.9 2.1 21.3 9.7 4.44 3.0 2.3 27.3 8.5 4.55 0.8 0.8 17.8 4.5 4.73 0.5 0.6 15.6 3.9 4.98 0.8 0.5 13.8 3.6 5.29 1.1 0.3 2.1 15.9 - 51 -water soluble (0.5 to 1.4 ppm), s imi l a r to that for exchangeable (0.5 to 15.0 ppm), but narrower than the ranges for reducible , ac t ive or EDTA extractable Mn. The resu l t s of th i s study support the theory (Page, 1962) that manganese becomes non-available through the formation of complexes with organic matter i n the s o i l since organic matter was found to be a s i g n i f i c a n t predictor for CaC^ extractable Mn, with pH as the next most important fac tor . The C a C ^ soluble Mn formed between 0.9 to 37.6% of ac t i ve , and 0.1 to 5.2% of t o t a l Mn (Table X I ) . I t i s in te res t ing to note that i n Hazelwood Ap, CaC^ soluble Mn formed 37.6% of ac t ive Mn i n the hor izon, but made only 1.3% of t o t a l Mn i n the same hor izon. A look at Cloverdale Ap, on the other hand, indicates that C a C ^ soluble forms 32.0% of a c t i ve , but 5.2% of t o t a l Mn. This comparison and the fact that a simple regression analysis indicated a s i gn i f i can t co r r e l a t i on between CaCl^ extractable and ac t ive , but not t o t a l Mn content substantiates the contention by Page e_t a l (1962) that t o t a l content of manganese i n a s o i l has l i t t l e connection with plant ava i lab le manganese. This further supports the suggestion by Leeper (1935, 1947) that "act ive manganese" content or the manganese wi th in the manganous-manganic•equilibrium i n the s o i l i s a more r e l i a b l e i nd i ca t i on of the s o i l ' s capacity to provide a plant with the required manganese. Values for water soluble Mn i n some ex i s t ing vegetation at the Cloverdale, Monroe and Sunshine s i t e s were 123.0, 29.5 and 2.0 ppm respec t ive ly . The values for t o t a l Mn i n the same order were 330.0, 472.0 - 52 -and 140.0 ppm. Since data on the vegetation are l imi t ed and also the vegetation involved d i f ferent species (Pasture or grass crop from Clover-dale s i t e ; Grass-legume from Monroe s i t e ; and Forest species from Sunshine s i t e ) , i t i s not possible to re la te the i r water soluble and t o t a l Mn values with s o i l manganese f rac t ions . However, there i s nothing unusual about the observed leve ls when compared with reported values (Walker and Barber, 1960). On the basis of the manganese contents i n the various types of vegetat ion, i t could be said that the amounts of reducible and ac t ive Mn i n the top horizons (12-17") of the selected s o i l s do correspond i n magnitude to the t o t a l Mn content i n the vegetat ion. How-ever, there i s no consistent re la t ionsh ip between the water so luble , exchangeable and t o t a l s o i l manganese from the s i t es and the t o t a l Mn i n the vegetat ion. The s igni f icance of the Manganese d i s t r i b u t i o n i n these s o i l s might best be discussed with reference to the chemical pool concept proposed by Vie t s (1962). According to V i e t s , the chemical pool i s simply the amount of an element i n a given state that can be estimated by ext rac t ion and i so top ic d i l u t i o n techniques. The chemical pool of each element i s assumed to have the a t t r ibutes of concentration, s i z e , turnover ra te , and equi l ibr ium with other pools of that element. In th i s study only the ext rac t ion technique i s being used to es tab l i sh the various manganese pools . Figure I I shows the o r i g i n a l pools of micronutrient cations i n s o i l , based l a rge ly on exchange and che la t ion react ions , as postulated by V i e t s . The diagram merely provides a convenience for understanding the - 53 -Figure I I . The Postulated Pools of micronutrient cations i n S o i l (after V i e t s , 1962). A. Water Soluble B. Cations exchangeable by a weak exchanger l i k e NR4 C. Adsorbed, chelated, or complexed ions exchangeable by other cations possessing high a f f i n i t i e s for exchange s i t e s or extractable with stronger chelat ing agents D. Micronutr ient cations i n secondary c lay minerals and insoluble metal oxides E. Cations held i n primary minerals - 54 -s o l u b i l i t y and a v a i l a b i l i t y of the micronutrient ca t ions . In Figure I I I an attempt i s made to re la te the resu l t s of t h i s study i n terms of th i s concept. A l l the pools A, B, C, D and E c o l l e c t i v e l y hold the t o t a l amount of manganese i n each s o i l . Pools A, B and C have been accounted for i n th i s study. Pools D and E, which have not been considered here, represent the secondary and primary manganese mineral forms respec t ive ly . These two pools would require more d ras t i c treatments for the i r so lu t ion . In addi t ion to the exchangeable (NH^OAc extractable) Mn, pool B could also represent the C a C ^ soluble Mn, since both are s imi l a r i n range. Pool A, the water soluble Mn, on the average accounted for less than 1% of t o t a l Mn. Pools B (exchange-able plus CaCl^ soluble Mn) and C (hydroquinone reducible and EDTA extractable Mn) accounted for 1.5% and 24.2% respec t ive ly . Thus pools D and E might account for more than 70% of the t o t a l Mn. I t i s a generally accepted fact that the effects of s o i l factors l i k e pH, organic matter content, redox po ten t i a l and concentration of other ions on the manganese ion affect the manganese cycle i n the s o i l , and hence the interconversion between pools A - B , B-C, C-D-E or E-D-A. For example poor aerat ion coupled with low pH can markedly increase the s ize of pools A and B (divalent Mn ion) . Most plants require r e l a t i v e l y small amounts of manganese, and a l l the s ix s o i l s studied would have had su f f i c i en t i f the manganese i n a l l the pools ( t o t a l s o i l Mn) had been a va i l a b l e . Pools A, B, and C are represented as being i n a revers ib le equi l ibr ium with one another as - 55 -Figure I I I . Possible Pools of Mn i n the Lower Fraser Val ley s o i l s . A. Water soluble Mn (range 0.5-1.4 ppm) B. Exchangeable or 1 N NH^OAc (pH 7) extractable Mn (range 0.5-15.0 ppm) C. Eas i l y reducible (by Hydroquinone) range: 0.7-119.5 ppm plus EDTA extractable after removal of ac t ive Mn range 0.9-227.2 ppm D & E. Inert or. less ac t ive forms of Mn A l l the pools from A to E c o l l e c t i v e l y make up the t o t a l amount of Mn i n the s o i l (found i n th i s study to range from 82.0 to 957.5 ppm.) - 56 -indicated by the double arrows i n Figure I I I . The amount of manganese i n these three pools appear to be r ead i ly ava i lab le to p lan ts . On the basis of the Beaverlodge Report (1969) and the resu l t s of th i s study the absolute amounts of A and B would appear the most important of a l l the pools for predic t ing adequacy of manganese to p lan ts . This i s a reasonable assumption since generally plants take up divalent Mn from s o i l so lu t ion (Leeper, 1947; Fujimoto and Sherman, 1948; Weir and M i l l e r , 1962). However pool C (representing r ead i ly reducible Mn oxides) i s of spec ia l s igni f icance to plants because of i t s s ize and because of the findings of Leeper (1947), Page (1962), Reid and Webster (1969) that the amount of reducible Mn i s a very essen t ia l measure of the manganese i n the s o i l that could be ava i l ab le to plants depending on the p reva i l i ng oxidat ion-reduct ion p o t e n t i a l . Values for hydroquinone reducible Mn (Table I I ) , which represent part of pool C, appear to be meaningful and lend support to the suggestions of these workers. Leeper found that s o i l s containing approximately 100 ppm of hydroquinone soluble manganese generally produced healthy p lants . I f the surface 6-12" of each p r o f i l e i s examined on th i s bas i s , i t i s possible to c l a s s i f y these s o i l s into manganese-deficient and manganese-sufficient categories . Thus, Milner and Monroe would be considered as having su f f i c i en t manganese to produce healthy p lants , but not G r e v e l l , Hazelwood, Cloverdale or Sunshine. However, basing such a c l a s s i f i c a t i o n on the range of CaC^ extractable Mn, a l l the s i x s o i l s might be considered capable of producing healthy p lan ts . While an evaluation of plant ava i lab le f rac t ion i s not possible i n th i s study, a general d iscuss ion suggests that c r i t i c a l l eve l s i n any - 57 -of these pools may not be important, since these l eve l s depend on methods of ex t rac t ion . I t appears essen t ia l to es tab l i sh such c r i t i c a l l eve l s i n these pools by using spec i f i c p lants . This study has shown the i den t i t y of these pools , but further study w i l l be necessary to reveal the equi l ibr ium and rates of interconversion that ex i s t among them. Again, without a further study of the s i t ua t ion involv ing plant uptake, i t w i l l not be possible to es tab l i sh a co r r e l a t i on between these pools and plant manganese requirements as found under the s o i l factors operating i n the Lower Fraser V a l l e y . By such studies and perhaps using a computer model i t would be possible to predict whether pools A, B or C could support plants by themselves or which combination of the three would give the best co r re l a t ion with plant uptake. - 58 -( SUMMARY AND CONCLUSIONS Mn status of s i x s o i l s from the Lower Fraser Val ley were examined. Water soluble Mn ranged from 0.5 to 1.4 ppm; Exchangeable Mn from 0.5 to 15.0 ppm; Hydroquinone reducible from 0.7 to 119.5 ppro; Tota l Mn from 82.0 to 957.5 ppm; and "act ive Mn" from 3.2 to 129.8 ppm. These ranges were s imi l a r to reported values, except that the study f a i l e d to f ind the high l eve l s of t o t a l Mn reported by Baker (1950) on some s o i l s from the same area. There was r e l a t i v e l y l i t t l e v a r i a -t i on i n water soluble and exchangeable Mn contents between s o i l s or wi th in p r o f i l e s . There was a considerable v a r i a t i o n i n l eve l s of reducible and t o t a l Mn, and also a considerable v a r i a t i o n i n d i s t r i b u t i o n wi th in p r o f i l e s . In four (Greve l l , Hazelwood, Cloverdale and Sunshine) out of the s i x p r o f i l e s , reducible and t o t a l Mn were higher i n the parent mater ia l than i n the surface horizons, which might be expected i n an area with high p r e c i p i t a t i o n and leaching such as the Lower Fraser V a l l e y . However, there was no sa t i s fac tory f i t for a number of the p ro f i l e s to the four d i s t r i b u t i o n patterns suggested by Leeper. EDTA extractable and ac t ive Mn have been used elsewhere as indices of manganese a v a i l a b i l i t y to p lants . Data on two p r o f i l e s indicate that both fract ions of Mn represent the same chemical form. However, further resu l t s suggest that the two Mn fract ions are d i f fe ren t . In nearly a l l samples wi th high organic matter content EDTA extracted more Mn after - 59 -removing "act ive Mn" than d i r ec t ext rac t ion with EDTA. These resu l t s are consistent with the suggestions that EDTA causes some dispers ion of s o i l p a r t i c l e s and also measures the manganese chelated by s o i l organic c o l l o i d s . P a r t i c l e s ize separation was car r ied out on selected samples using u l t rasonic dispers ion i n d i s t i l l e d water. Mn fract ions were determined on the s o i l separates. Mn l ibera ted through the dispers ion treatment was higher than the normally determined water soluble f r ac t i on . Less of the exchangeable Mn was found i n the f ine than i n the coarse f r a c t i o n , whereas 60-90% of reducible Mn occurred i n the coarse f r a c t i o n . A greater proportion of t o t a l s o i l Mn also occurred i n the >2y f r a c t i o n . Thlts d ispers ion led to subs tant ia l increase i n recovery of a l l forms of Mn, more espec ia l ly the hydroquinone reducible form. In add i t ion , the recovery of t o t a l Mn exceeded that normally determined after perchlor ic ac id d iges t ion ; suggesting that the v a l i d i t y of conventional "reducible" and " t o t a l Mn" ext rac t ion methods should be re-examined. The resu l t s also suggest that the assumption that sonic dispers ion causes no modif ica-t i on of s o i l constituents i s questionable. S t a t i s t i c a l techniques were used to examine the re la t ionsh ip between Mn d i s t r i b u t i o n and the two types of parent mater ia ls , pH, organic matter content and C . E . C . A stepwise regression analysis was used to determine which of these s o i l factors were the best predictors of the - 60 -various manganese f rac t ions . These analyses show that the l e v e l of Mn fract ions i n the s o i l cannot be predicted by any s ingle fac tor , but by a number of s o i l fac tors . The resu l t s suggest that i t may be possible to • b u i l d up a computer model to predict the d i s t r i b u t i o n of s o i l Mn and i t s uptake by plants using three or more s o i l factors as inputs . The s igni f icance of s o i l Mn d i s t r i b u t i o n i n terms of plant requirements was discussed. Plant ava i lab le Mn i n these s o i l s was estimated by 0.02 M CaCl^ ex t rac t ion . This ranged from 0.5 to 10.7 ppm which was very s imi l a r to the l eve l s of exchangeable Mn. The CaCl^ soluble Mn showed higher co r r e l a t i on wi th "ac t ive" than with t o t a l Mn; thus substant iat ing the contention that t o t a l content of Mn i n the s o i l has l i t t l e connection with plant ava i lab le Mn and that "act ive Mn" i s a more r e l i a b l e measure. Using ext rac t ion techniques only, various Mn pools were established for these s o i l s according to the chemical pool concept proposed by V i e t s . These pools were discussed wi th the i r possible r e l a t i o n to manganese a v a i l a b i l i t y . Based on data i n the l i t e r a t u r e these s o i l s were c l a s s i f i e d into Mn-deficient and - s u f f i c i e n t categories . However, due to the v a r i a b i l i t y associated with predic t ing ava i lab le Mn from an extrac-t i o n technique alone, i t was concluded that a further study invo lv ing plant uptake was necessary to es tab l i sh a co r r e l a t i on betx^een the pools and plant manganese requirements; and also to reveal the e q u i l i b r i a and rates of interconversion ex i s t i ng between the established pools as found under the s o i l conditions of the Lower Fraser V a l l e y . - 61 -LITERATURE CITED 1. Amer, F . , Bouldin, D .R. , Black, C . A . , and Duke, E.R. 1955. Character izat ion of s o i l phosphorus by anion exchange r e s i n adsorption and P-32 e q u i l i b r a t i o n . Plant and S o i l 6:391-408. 2. Baker, J . 1950. D i s t r i b u t i o n of Mn i n B .C . s o i l s . M.S .A. Thesis . Dept. of Agronomy ( S o i l s ) , U .B .C . (Unpublished). 3. Bear, F . E . 1946. So i l s and F e r t i l i z e r s . New York. John Wiley and Sons, Inc. p. 51. 4. Beeson, K . C . , Gray, L . , and Adams, M.B. 1947. Absorption of mineral elements by forage plants I . J . Am. Soc. Agron. 39: 353-362. 5. B j e r r i ng , J . H . , Dempter, J . R . H . , and H a l l , R .H. 1968. U . B . C . TRIP (Triangular Regression Package). Univ. of B r i t i s h Columbia Computing Centre. 6. Black, C.A. 1965. Methods of s o i l ana lys i s . Parts I and I I . Amer. Soc. Agron. , Inc . , Publisher Madison, Wisconsin, U . S . A . 7. Boken, E. 1958. Investigations on the determination of the ava i lab le Mn content of s o i l s . Plant and S o i l 9: 269-285. 8. Browman, M . G . , Peterson, L . A . , and Chesters, G. 1970. A v a i l a b i l i t y and e x t r a c t a b i l i t y of s o i l Mn i n a l iming experiment. S o i l S c i . and P i Analys is 1: 21-26. 9. Christensen, P . D . , Toth, S . J . , and Bear, F . E . 1950. Status of s o i l Mn as influenced by moisture, organic matter, and pH. S o i l S c i . Soc. Amer. Proc. 15: 279-282. * 10. Coppenet, M . , and Calvez, J . 1952. Dosage du manganese a c t i f dans les terres de Bretagne. Ann. Agron. 3: 351-358. 11. Cotton, F . A . , and Wilkinson, G. 1962. Advanced inorganic chemistry. Interscience Publ ishers . 12. D'Agostino, 0. 1938. Dosaggio d e l ' a t t i v i t a chimica de l d ioss ido d i manganese. R i c . S c i . 9(1): 195-206. (Cited by Leeper, 1947). - 62 -13. Day, F . H . 1963. The chemical elements i n Nature. Reinhold Publ . Corp. New York. 14. Dion, H . G . , and Mann, P . J . G . , 1946. Three-valent Mn i n s o i l s . J . Agr. S c i . 36: 239-245. 15. Dion, H . G . , Mann, P . J . G . , and Heintze, S.G. 1947. The ea s i l y reducible Mn of s o i l s . J . A g r i . S c i . 37: 17-22. 16. Edwards, A . P . and Bremner, J . M . 1967. Dispersion of s o i l p a r t i c l e s by sonic v i b r a t i o n . J . S o i l S c i . 18: 47-63. i 17. Finck, V . A . 1954. Z. Pflanzenernahr; Dung., Bodenkunde 67: 198-211. (Cited by Hoff and Mederski. 1958. S o i l S c i . Soc. Amer. Proc. 22: 129-132). 18. Fujimoto, C . K . , and Sherman, G.D. 1945. The effect of dry ing , heating and wetting on the l e v e l of exchangeable Mn i n Hawaiian s o i l s . S o i l S c i . Soc. Amer. Proc. 10: 107-112. 19. Fujimoto, C . K . , and Sherman, G.D. 1948. Behaviour of Mn i n the s o i l and the Mn c y c l e . S o i l S c i . 66: 131-145. 20. G i s i g e r , L . 1935. Landw. Jahrb. Schwiez: 735-748. (Cited by Leeper, 1947). 21. G i s ige r , L . , and Hasler , A. 1948. Neure Beobachtungen Uber Die Ursachen Der Dorrfleckenkrankheit Beim Hafer. Plant and S o i l 1: 18-50. 22. G r i l l , E . V . , Murray, J .W. , and MacDonald, R.D. 1968. Todorokite i n manganese nodules from a B .C . F jord . Nature (London) 219: 358-359. 23. Hasler, A. 1951. Schweiz. Landw. Monatsh. 29: 300-305. (Cited by Mulder and Gerretsen, 1952). 24. Heintze, S.G. 1938. Readily soluble Mn of s o i l s and marah spot of peas. J . Agr. S c i . 28: 175-186. 25. Heintze, S.G. 1946. Mn deficiency i n peas and other crops i n r e l a t i o n to the a v a i l a b i l i t y of s o i l Mn. J . Agr. S c i . 36: 227-238. 26. Heintze, S.G. 1956. The effects of various s o i l treatments on the occurrence of marsh spot i n peas and on Mn uptake and y i e l d of oats and timothy. Plant and S o i l 7: 218-236. - 63 -27. Heintze, S.G. 1957. Studies on s o i l Mn. J . S o i l S c i . 8: 287-300. 28. Heintze, S .G . , and Mann, P . J . G . 1947a. Soluble complexes of manganic manganese. J . Agr. S c i . 37: 23-26. 29. Heintze, S .G . , and Mann, P . J . G . 1947b. Divalent Mn i n s o i l ex t rac ts . Nature (London) 158: 791-792. 30. Heintze, S .G . , and Mann, P . J . G . 1949a. Studies on s o i l Mn. Part I . Pyrophosphate as extractant of s o i l Mn. J . S o i l S c i . 2: 234-242. 31. Heintze, S .G . , and Mann, P . J . G . 1949b. Studies on s o i l Mn. J . Agr. S c i . 39: 80-95. 32. Hemstock, G . G . , and Low, P . F . 1953. Mechanisms responsible for the re tent ion of Mn i n the c o l l o i d a l f r ac t ion of s o i l . S o i l S c i . 76: 331-343. 33. Hewett, D . F . , and F le i sche r , M. 1960. Deposits of manganese oxides. Econ. Geol . 55: 1-55. 34. Hewett, D . F . , F le i sche r , M . , and Conkl in , Nancy. 1963. Deposits of the manganese oxides-Supplement. Econ. Geol . 58:1-51. 35. H i l l , A . C . , Toth, S . J . , and Bear, F . E . 1953. Cobalt status of New Jersey s o i l s and forage plants and factors af fect ing the cobalt content of p lan ts . S o i l S c i . 76: 273-284. 36. Hopkins, E . F . , Pagan, U . , and Ramirez-Si lva , F . J . 1944. J . Agr. Univ. Peurto Rico 28: 43-101. (Cited by Mulder and Gerretsen, 1952). 37. Jackson, M.L . 1958. S o i l chemical ana lys i s . P r e n t i c e - H a l l , Inc. p. 332. 38. Jackson, H . G . M . , and Swanback, T.R. 1932. Manganese content of ce r t a in Connecticut s o i l s and i t s r e l a t i o n to the growth of tobacco. J . Amer. Soc. Agron. 24: 237-245. 39. Jones, L . H . P . , and Leeper, G.W. 1951. Ava i l ab le manganese oxides i n neutra l and a lka l i ne s o i l s . Plant and S o i l 3: 154-159. 40. K e l l e y , W.P. 1909. Mn i n some of i t s r e la t ions to the growth of pineapples. J . Ind. Eng. Chem. 1: 533-538. 41. Leeper, G.W. 1935. Manganese deficiency of cereals : P lo t experiments and new hypothesis. Proc. Roy. Soc. V i c t o r i a 47: 225-261. - 64 -42. Leeper, G.W. 1947. The forms and reactions of Mn i n the s o i l . S o i l S c i . 63: 79-94. 43. Lingane, J . J . 1966. A n a l y t i c a l chemistry of selected me ta l l i c elements. Reinhold Publ ishing Corp. New York. 44. Lohnis, M.P. 1946. T i jdschr . Plantenziekten 2: 157-160. (Cited by Mulder and Gerretsen, 1952) . 45. Lohnis, M.P. 1951. Mn t o x i c i t y i n f i e l d and market garden crops. Plant and S o i l 3: 193-222. 46. Main, R . K . , and Schmidt, C . L . A . 1935. Combination of d ivalent Mn wi th p ro te in , amino ac ids , and re la ted compounds. J . Gen. P h y s i o l . 19: 127-147. 47. Mann, P . J . G . , and Quastel, J . H . 1946. Mn metabolism i n s o i l s . Nature (London) 158: 154-156. 48. Mar t i n , J . P . , Harding, R . B . , and Murphy, W.S. 1953. Effects of various s o i l exchangeable ca t ion r a t io s on growth and chemical composition of c i t r u s p lants . S o i l S c i . 76: 285-295. 49. Maschhaupt, J . G . 1934. Z. Pflanzenernahr; Dvingung U . Bodenk. B 13: 313-320. (Cited by Mulder and Gerretsen, 1952). 50. Mattson, S . , Er iksson, E . , and Vahtras, K. 1948. Lantbruks-Hogskol. Ann. 15: 291-307. (Cited by Mulder and Gerretsen, 1952). 51. McCool, M.M. 1934. The effect of various factors on the soluble Mn i n s o i l s . Boye Thompson Inst . Conbrib. 6: 147-164. 52. McHargue, J . S . 1923. Effect of Mn on plant growth. J . Agr. Res. 24: 781-794. 53. M e l l o r , D . P . , and Mal ley , L . 1948. Order of s t a b i l i t y of metal complexes. Nature 161: 463-467. 54. Mero, J . L . 1962. Ocean Floor manganese nodules. Econ. Geol . 57: 747-767. 55. M i s r a , S .G . , and Mishra , P .C . 1969. Forms of Mn as influenced by organic matter and i ron oxide. Plant and S o i l 30: 62-70. 56. Mulder, E . G . , and Gerretsen, F . C . 1952. S o i l Mn i n r e l a t i o n to plant growth. Adv. i n Agron. 4: 221-277. - 65 -57. Naf t e l , J . A . 1934. The glass electrode and i t s app l i ca t ion i n s o i l a c i d i t y determinations. S o i l Res. 4: 41-50. 58. Nicholas , A . R . , and Walton, J . H . 1942. The autoxidat ion of manganous hydroxide. J . Amer. Chem. Soc. 64: 1866-1870. 59. Page, E.R. 1962. Studies i n s o i l and plant Mn I I . The r e l a t i o n -ship of pH to Mn a v a i l a b i l i t y . Plant and S o i l 16: 247-257. 60. Page, E . R . , Schofield-Palmer, E . K . , and McGregor, A . J . 1962. Studies i n s o i l and plant Mn I . Manganese i n s o i l and i t s uptake by oats. Plant and S o i l 16: 238-246. 61. Passioura, J . B . , and Leeper, G.W. 1963. Ava i l ab le Mn and X-hypothesis. Agrochimica 8: 81-90. 62. P iper , C.S . 1931. The a v a i l a b i l i t y of Mn i n the s o i l . J . Agr. S c i . 21: 762-779. 63. Ponnamperuma, F . N . , Loy, Teres i ta A . , and Tianco, E s t r e l l a M. 1969. Redox e q u i l i b r i a i n flooded s o i l s : I I . The manganese oxide systems. S o i l S c i . 108: 48-57. 64. Popp, M. , Contzen, J . , and Gericke, S. 1934. Z. Pflanzenernahr. Dlingung U. Bodenk B 13: 66-73. (Cited by Mulder and Gerretsen, 1952). 65. Reid , A . S . J . , and M i l l e r , M.H. 1962. The Mn cycle i n s o i l I I . Forms of s o i l Mn i n equi l ibr ium with so lu t ion Mn. Can. J . S o i l S c i . 43: 250-259. 66. Reid, A . S . J . , and Webster, G.R. 1969. The Mn status of some Alber ta s o i l s . Can. J . S o i l S c i . 49: 143-150. 67. Remy, H. 1966. Treat ise on inorganic chemistry.. V o l . 2. E l sev ie r Publ ishing Co. Amsterdam. 68. Report of meeting on s o i l a c i d i t y and l iming at Research S ta t ion , C D . A . Beaverlodge, A lbe r t a . 1969. (Unpublished). 69. Robinson, W.O. 1929. Detection and s igni f icance of MnO, i n s o i l . S o i l S c i . 27: 335-350. 70. Samuel, G . , and P iper , C.S. 1929. Mn as an essen t ia l element for plant growth. Ann App l . B i o l . 16: 493-534. - 66 -71. Sanchez, C , and Kamprath, E . J . 1959. Effect of l iming and organic matter on the a v a i l a b i l i t y of native and applied Mn. S o i l S c i . Soc. Amer. Proc. 23: 302-304. 72. Seekles, L . 1950. Lotsya 3: 119-141. (Cited by Mulder and Gerretsen, 1952). 73. Se rdobo lsk i i , E .P . 1950. The effects of s o i l condit ions on the transformations of manganese compounds i n the s o i l . Trudy Pochv. Inst . Dokuchaev. 43: 192-216. 74. Se rdobo lsk i i , N . P . , and Sinyagina, M.G. 1953. A l k a l i - a c i d conditions for formation of soluble organic compounds i n manganese. Pochvovedenie 7: 43. 75. Sherman, G.D. 1950. Correct ing trace-element de f i c i enc i e s . F e r t i l i z e r Review 25: 12-14. 76. Sherman, G .D . , and Harmer, P .M. 1942. The manganous-manganic equi l ib r ium i n s o i l s . S o i l S c i . Soc. Amer. Proc. 7: 398-405. 77. Sherman, G .D . , McHargue, J . S . , and Hodgkiss, W.S. 1942. The production of lime induced Mn def ic iency on an eroded Kentucky s o i l . J . Amer. Soc. Agron. 34: 1076-1083. 78. Sherman, G .D . , McHargue, J . S . , and Hodgkiss, W.S. 1942. Determina-t i o n of ac t ive Mn i n s o i l . S o i l S c i . 54: 253-257. 79. Sb'hngen, N . L . 1914. Zentr. Bakt. I I . 40: 545-554. (Cited by Mulder and Gerretsen, 1952). 80. Steenbjerg, F . 1935. The exchangeable Mn i n Danish s o i l s and i t s r e la t ionsh ip to plant growth. Trans. In t . Soc. S o i l S c i . (Third Congress, Oxford) 1: 198:201. 81. Taylor , R . M . , and McKenzie, R.M. 1966. The associa t ion of trace elements with manganese minerals i n Aus t ra l i an S o i l s . Aust . J . S o i l Res. 4: 29-39. 82. Taylor , R . M . , McKenzie, R . M . , and Nor r i sh , K. 1964. The mineralogy and chemistry of Mn i n some Aus t r a l i an s o i l s . Aust . J . S o i l Res. 2: 235-248. 83. Trocme, S. , and Barbier , G. 1950. Sur 1 ' i nac t iva t ion dans le s o i l des sels manganeux employes comme engras. Comptes Rend. 230: 572-574. - 67 -84. V i e t s , F . G . , J r . 1962. Micronutr ient a v a i l a b i l i t y : Chemistry and a v a i l a b i l i t y of micronutrients i n s o i l s . J . Agr. Food Chem. 10: 174-178. 85. Wadsley, A . D . , and Walkley, A. 1951. The structure and r e a c t i v i t y of the oxides of manganese. Rev. Pure Appl . Chem. 1: 203-213. 86. Wain, R . L . , S i l k , B . J . , and W i l l s , B .C . 1943. The fate of manganese sulphate i n a l k a l i n e s o i l s . J . Agr. S c i . 33: 18-22. 87. Walker, J . M . , and Barber, S.A. 1960. The a v a i l a b i l i t y of chelated Mn to m i l l e t and i t s e q u i l i b r i a with other forms of Mn i n the . s o i l . S o i l S c i . Soc. Amer. Proc. 24: 485-488. 88. Wangersky, P . I . 1964. Manganese i n Ecology. Chem. Abst r . 60 No. 2; 1488. 89. Weir, C C . , and M i l l e r , M.H. 1962. The Mn cycle i n s o i l . I . I so top ic -exchange react ion of Mn-54 i n an a lka l i ne s o i l . Can. J . S o i l S c i . 42: 105-114. 

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