The relative significance of iron-binding and aluminium-binding of phosphate in soils representative of the main New Zealand genetic groupings as revealed by fractionation methods and by phosphate fixation studies in the laboratory : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science (Horticulture)

Copyright is owned by the Author of the thesis. Permission is given for

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-mlRILAffVJIS~a,

Dlf - BDlllDC .Gm .AUMIN Cull - BDml1C

a,

R&mBl1'B D SOILS BIPBBSEl'lN1Tf' Zl&tlffl> Q88BflC CIOtJPJJDS AS JIIVB&mD Br J'1llC'l'IOIIAn IB'.lB>m A1ID Bf PlllS8IAD PI1ATIOll SNJU..a Ill

E.

a.

^Ooh

- 1962 -

TAJU "' M'lJ!P

?Me.

I: J.. Introduction l

B. Ren.ew

~ literature

1.

^The tractiODation of aoil pboaphorua

2.

The retention

ot

phoapbate by iron

and almdu:tna OOllpOllnda of IOUa 10 II: B'l'ElqAIA.

De-acrlption of aoila.

lS

XII:

BIPBRimTAL·

1.

Preparation

ot

aoil aaaplea 24

2. Determination of Ji{ 24

,.

Detel'llination of free 1Mll oxides

24-

,.._

Detemination

ot

phosphate

24-

s.

Practionation procedurea

&. 'rb9 detel'llination

ot

a)kal1

-

aoluble aoil phosphate

I>. 'l.'he detenination of aluainiua - boun4 aoil pboaphate

\

^{o .. The} detemlnation

ot

iron -

bound 80il ph,Japb&te

,.

^!'be de'temlnat1on o~ pbo-,bate

1'1t'tellUoD by ~ . , - treatecl aoUa

ta

0.5 M lf\Cl

a.t auferent

pl J.e•l•

7.

^tfbe deteNitu•U•

or

pboaphate

ntenticm lo' -.treated" aoUa n

albl tne JIii 1••1•

8. The de mtna.t1on

or

pboaphate NtenUCIII

t,y

W8'11 -

trea.te4 aolla at AlblSne ;«

^1ewla

IV:

IISUJIS - - • ·

1.

h'N ha

oz14e oontenta ot tbe aoila 32

'!ABLE Cit Cu.imW.l'S

(Cont'cl)

bi!.

2.

Soll

ptaoaphate h'aotiona

35

,.

^Phoaphate

retention

^{aholm by tb9 aoila}

at

clitterent pH Yaluea in

0.5 • IBJ..Cl.

f'ol.l.cnd..ng dealllllination by

o.s •

^D₄^{P YI}

4• Pboaph :te retention shown by "untreated•

10ila at alka.Une pH Yalues 1n

O.S •

ffl\.Cl

5.

Pbo-aphate retention shown by the aoila at alkaline p8 T&luea in

0.5 •

^1'J\.Cl

after treat.eat

with 1.0 If.OB

,.

Coapar11ema ~ the pbaaphate retention shom by fluoride treated end "untreated•

aoUa at f'our aelected pH leve.18

in

the

alk&J1ne ftl'l81'·

.51

7.

Correl.ation

ot

phosphate retention

Yal.uea of' fluor14e treated aoila with the

tree

iron oxide contents ~

tm

aoila

57

V:

General Diswasion

.58

~ 6o

._-1 : , • ..L-_'l..! -• a

Tt&B·

1. Deacriptlon of aoila

16

2. Cheaical. and llineralogioal data 20

3. Soll

pboaphate

tractiou J7

4,. Ccapari•n•

ot

phosphate retention lbown by t'luorlde treated and "untreated• aoila at

tour aeleoted pR value a in th9 alkaline range

.5 l

B. l'ICURBS.

1. The relationship between pH and phoaphate

retention aho1n by tour acma1. aoila after

JIB,!

treatment, l'aOR treataent and no treataent

2. The relationahip between pH and phosphate retention ahom by tour aonal aoil a af'ter

~ P treatment, NaOH treatment and no treatment 4-7

3.

The relationship between pH end phosphate retention abo1'D by two aonal aoila and two intrasonal soil a a:rter llB.4-P treatment, l'aOH treataent and no treat.nt

4,. The rel.atlonabip between pB and phosphate

retent1oa

ahown by a1lc intrucmal

aolla

atter _{E 4P} treataant, and no

t-reataent

s.

^The relatiould.p betwea pB

am

pboaphat.

retention

ahown by

fie

intruanal

ancl one

amnal ac,ila after

11\,P taataent,

^Sa0B

tre&tal

t

a4 DO

t-reataent

- 1 -

J.

.a. .

^{~•~ -• f I jl >p t}

.Althougti a gnat

bocJ1' ot

e-d4ence points to the preaenoe ~

iron - and abw1n119 - bounc1 plloapbate 1n aoila u produota

ot

the pboaph&te fixation prooeaa, until reoentJ.T no aatiaf"aetory prooedurea

b&Ye 'bee aTallable tor the qwmtitati w uee.aaent ot the IIIC>1.Ulta

ot tbeae toraa in

aoila.

Chang

and Jaakaon

(1957)

wre

the

tirat 1Drkera ^t.o propose a aobe1le ot pboaphate tractionation, which included the aeparate deter- aination ot il"on - and al.11111niua - bound pho sphatea. The lllli tationa

ot

their prooedure haft been diacuaaed by J'if'e (1959a, 1959b and 1962) ,

who baa proposed (1962) a IIOCli1'1ed . . thod tor

the

detel'llination

ot

the aluain1ua - bound soil phoaphate traction. Fite (unpublished resulta) hu aubaequently inoorporated this proceclure into a general

scbeae ot aoil phosphate fractionation, which ino1udea the aelecti.e dete:ndnation

or

iron - bound and calciua - bound pboaphatea.

The iron - and all.mini\111 - bound f'ol'lla ~ phoapbate 1n aoila are

ot

secondary origin derived in the ca.se ot vh'gin IOila troa or.1g:ln&1.

apatite and in the cue

ot

tertilise4 aoila by tixation ot applied pboapbate. Tbeir proportionate incidence in 1/fltT given aoil ia a

retlection or

the

relatiYe

tendency

tor

iron an4 alain1ma COllpOWlda

to

t1z pboaphate deriftd l,y wather.lng

ot

apatite or traa 1144N

pboapbate tertili•ra• It wu oonai4ered.

ot

interest

to

inwat1gate whether the ratio

t

iroa -

to

e.luatnia - bound pbl,aphate 1a a nnge

ot . . .

Zealancl eoila tollowcl - , p ttem wld.ch ooal.4 be l1nte4

with the estaibllahe4 geaeUo olaadtioation ~ the• aoUa. It wu t'urther aon.U.1"94

ot

intenat to lnftatigate wbetber a relationabip ezlated betwen the ratio

ot

the• tol"II•

rounc1

in tlel4 aoila m4 that

toan4 by la1aoratory thatioa

ataa!a•.

- 2 -

Joy- laboratory • ~

ot

the relat1w contribution ~ iron IID4 alum:hd.wa ooapoanda

to

^the phosphate f'!x&tin process deaanda a prooeclure f'or the l'ellOYal ~ om ot these oompounda ao that the pboaphate ~ta1n1ng propertiea ~ the other ae;y be in-.eatlgatecl.

Ic1eall;r the f1xlng oapaci ty ahould be studied (a) atter clealuaination,

(b)

after def'erration,

and the awmaatlon

ot

these quantities OOll.p&l"ed with the phosphate f1xiDg

capaoity of

the

who1e aoil.,

atop• being tabm ill &1.l

caaea

t.o ensure that &Jkal1ne earth cations, which aq fix phosphate by

precipitation reactions, are first removed trom the syateaa.

Unfortunately there appears

to

be no prooedure whereby iron oxidea om be reaoved froa aoila without aimul.taneoua remoYal ot alwainiua.

Pit"e (unpiblllheddata) has., howeffr, concluded that prolonged treatment of aoila w1 th 0.5 V lfil1.l at pH

8.5

llhoul.d cOllplet.ely elillinate

aluainiua - binding

ot

phosphate by virtue of the

abiliV

^of this reagent to tom oomplex ions with aluainium but not with iron at thia pll Yalue. Soila dealwdnated in this 1119' ahould therefore aene tor

atuM. a on pboaphate retention by free iron ozidea. Stror,aq a1W1ne aolut1ona S'Uob aa l • ^1'af)II -.y al.lO be ezpeoted to acbiew doaluaination through the toraation

ot

aol.ubl• &1.uainatea.

loth

the•

aetbou wre irmtat1gate4 1n the preaent • ~ •