This article was downloaded by: [98.162.159.199]On: 15 November 2014, At: 10:01Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954 Registeredoffice: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK

Soil Science and Plant NutritionPublication details, including instructions for authors andsubscription information:http://www.tandfonline.com/loi/tssp20

Correlation of soil tests with pot andfield trials in the evaluation of soilfertilityR. V. Tamhane a & B. V. Subbiah aa Indian Agricultural Research Institute , New DelhiPublished online: 29 Mar 2012.

To cite this article: R. V. Tamhane & B. V. Subbiah (1962) Correlation of soil tests with pot andfield trials in the evaluation of soil fertility, Soil Science and Plant Nutrition, 8:3, 5-14, DOI:10.1080/00380768.1962.10430991

To link to this article: http://dx.doi.org/10.1080/00380768.1962.10430991

PLEASE SCROLL DOWN FOR ARTICLE

Taylor & Francis makes every effort to ensure the accuracy of all the information (the“Content”) contained in the publications on our platform. However, Taylor & Francis,our agents, and our licensors make no representations or warranties whatsoever as tothe accuracy, completeness, or suitability for any purpose of the Content. Any opinionsand views expressed in this publication are the opinions and views of the authors,and are not the views of or endorsed by Taylor & Francis. The accuracy of the Contentshould not be relied upon and should be independently verified with primary sourcesof information. Taylor and Francis shall not be liable for any losses, actions, claims,proceedings, demands, costs, expenses, damages, and other liabilities whatsoever orhowsoever caused arising directly or indirectly in connection with, in relation to or arisingout of the use of the Content.

This article may be used for research, teaching, and private study purposes. Anysubstantial or systematic reproduction, redistribution, reselling, loan, sub-licensing,systematic supply, or distribution in any form to anyone is expressly forbidden. Terms &Conditions of access and use can be found at http://www.tandfonline.com/page/terms-and-conditions

[Soil Science and Plant Nutrition, Vol. 8, No.3, 1962)

CORRELATION OF SOIL TESTS WITH POT AND FIELD TRIALS IN THE EVALUATION

OF SOIL FERTILITY

R. V. TAMHANE AND B. V. SUBBIAH

Indian Agricultural Research Institute, New Delhi

RECEIVED AUGSUT 7, 1961

Introduction

. The practical importance of soil tests in bring­lUg about efficient use of fertilizers is well estab­lished. Extensive areas in India are producing Only a fraction of their yield potential due to the lack of enough plant nutrients whose need could be easily assessed by soil tests and suitable re­commendations of fertilizer use to increase crop production could be given.

Twenty-four soil testing laboratories have been established throughout the country for assessing the fertility status of farm lands and to advise the farmers on fertilizer use. In this paper (1) basic work needed on the suitable methods to establish the soil testing service, (2) the trends in the soil fertility levels as revealed by the soil tests conducted so far and (3) further research work that is envisaged to put the soil testing service On sound basis are discussed.

Development of Soil Testing Methods

b Soil tests to be of any value as a guide, must ~ capable of distinguishing between soils of

different nutrient levels. This will be possible Only if the soil testing methods are carefully calibrated against crop responses in pot culture and field experiment.

In the past, due to the absence of detailed correlation work between soil analyses and crop resPonses, the total plant nutrients were analysed and certain limits were fixed to classify the status ~s rich, fair and poor. The following classifica­tlo.n Was given by Sahasrabudhe (1929) for the s~ll analysis based on Hel extract. While this c. assification gave a general picture of the poten­~Ial supply of the nutrients, it did not give any In?ication regarding the likely response or other­\VIse to fertilizer application.

In order to initiate the soil testing work in

5

Table I (a) Levels of '}'o total nutrients classified as rich, good, fair or poor .

I Rich I Good Fair Poor

N 0.1 10.06 to 0.1 0.03 to 0.06 below 0.03

P20. non-clay 0.1 0.06 to 0.1 0.03 to 0.06 beiow003 soils

clay soils 0.2 0.1 to 0.2 0.05 to 0.1 belowO.OS

K,O non-clay 0.2S O.lS to 0.2S O.OS to O.lS belowO.OS soils

clay soils 0.3 0.2 to 0.3 0.07 to 0.2 below 0.07

India and develop fertilizer recommendations on sound lines, some preliminary work was carried out on the calibration of the soil test values with crop response to fertilizers. A review of the limited work carried out earlier on Indian soils is given below in respect to three major nutrients, namely-phosporus, potash and nitrogen.

Phosphorus: Use of chemical extractants for estimating

available phosphate and assessing the need for the phosphatic fertilizers or otherwise has been made in the past by many workers, and out of many methods DYER's 1 % citric acid method received the greatest attention. LEATHER (1907) working on some representative Indian soils ob­tained the limits of phosphate response by the DYER-s method to be below 0.05% except in the case of laterite soils for which a much higher limit of 0.11 % was fixed. In calcareous soils, DAS (1926) found extraction with potassium carbo­nate to give more satisfactory results for phos­phate than with other dilute acid extractants. These earlier studies, however, lacked systematic attempts to correlate between the analytical re­sults and the crop responses to fertilizers.

In recent years more intensive work was car­ried out in India to evaluate the methods of estimating available phosphorus for assessing the

(97)

Dow

nloa

ded

by [

98.1

62.1

59.1

99]

at 1

0:01

15

Nov

embe

r 20

14

R. V. TAMHANE AND B. V. SUBBIAH

suitability of different methods and for deter­mining the limits of response or lack of response.

In red and lateritic soils of pH varying from 5 to 7, significant correlation coefficient between available phosphorus values by TRUOG'S method and responses of rice crop to superphosphate was obtained (RAYCHAUDHURI, SUBBIAH & SINHA (1954)). DATTA and KAMATH (1958) reported that for may Indian soils, OLSEN's sodium bicarbonate method (1954) gave highest correlations in the case of paddy and wheat in both pot and field experiments. The usefulness of the OLSEN's method in soils of pH of above 6 and of BRAY's method for soils below 6 for assessing phosphatic fertilizer needs in India was further confirmed by TAMHANE et al (1958, 1959) in pot culture ex­periments. Thus in Delhi, sandy loam soils, available phosphorus by OLSEN's method gave the highest correlation of 0.78 with percentage yields of wheat, which is significant at 1 % level (Fig. 1).

Fig. 1. Relation between available 'jI (OUEN'S

method) and percentage yield (wheat).

In all India soils, with wheat crop, the available phosphorus obtained by OLSEN's method showed the highest correlation (0.911) with phosphorus uptake by wheat crop. In soils of pH varying from 5 to 7, BRAY's method using 0.1 N HC1+ 0.03 N NH,F gave highest correlation of 0.83 significant at 1 % level. In table II (a) is given the data obtained by different workers in India on the correlation between soil available phos­phorus by different methods on paddy and wheat crop responses to fertilizers.

The work so far carried on has shown that in

(98) 6

Table I (b) Correlation coefficients between surface soil and subsoil nutrient values.

Available P

Available N

Available K

6-12" I

0.93**

0.82*

0.75

12-18/1 I 18-24" I~ 0.84** 0.82 0.86** I

0.81 0.91l~ 0.70

0.60 I 0.31 0.17 --------** Significant at 1 % level * Significant at 5 % level

general soils testing less than 20 Ibs. PaO, give a good response while soils with 20 to 50 lbs. PzO, give medium response to the applications of phosphatic fertilizers. Soils testing above 50 Ibs give little or no response.

Potassium: LEATHER (1907) using DYER's method reported

that P responses to potassic fertilizers are only slight in Indian soils even with 0.0027% available K.O. SEN, DEB and EOSE (19,(0) found that all

lateritic soils which were studied by thetll with very few exceptions contained much less than 15.20 mgs. exchangeable K pet 100 gms. of soil and that they were likely to respond to fertilizers. MUKHERJEE:, MANDAL and MUKHERJEE (1955) concluded on the basis of their work in Bihar soils that percentage K saturations will be II

more reliable index for K response than the net amount of exch. K. Recent cot­relation studies by T AMHANE, SUBBIAH and OOMMEN (1958) in both pot and field elC­periments on all India soils indicated that no single extractant is likely to be suitable for all India soils and exch. K as detet­mined by ammonium acetate appears to be no good index of the soil to suppl1 potassium to crops. MORGAN's extractant

soluble K, percentage saturation and dilute nitriC acid soluble K showed moderately good corte-1 · . h 1" of atlOns Wit crop responses to app !CatIOns f potassic fertilizers in red and lateritic soils 0

Bihar, acid alluvial soils of Kerala and West Coast alluvial soils of Mangalore respectivelY­In pot culture experiments, OOMMEN (1959) te-ported that in the case of light soils, there WI!:' a high correlation (r=0.93 significant at 1% leve

between percentage K saturation value and pa~d~ crop responses to K. The correlation coefficlen

obtained by different methods for available pota-

Dow

nloa

ded

by [

98.1

62.1

59.1

99]

at 1

0:01

15

Nov

embe

r 20

14

CORRELATION OF SOIL TESTS WITH POT AND FIELD TRIALS IN THE EVALUATION

'" ~ ]..!!l I 1--4 '0 f;:s -m a. < ~

'" ii5 :.e .h t::..!!l 1--4 'S =m =:

~ <t: -= ..0 ::: '" ~~ t: v o v

S mll .;:: .-~ ~ =-Ol '" >< 0-

"'-l Ol ...

.~ ~ ,;::

"g..!!l ~ U 1--4'0

'" '0 :=m ~ <t: ... Cl.

~ 0. ..!!l '" 0 "0 '15 j ..0 Cl. .'!l c:: Vl,oo!'4

t:: "'QJ~ Ol al'E S 8 p::~o .;:: ~ j...':: ><

"'-l

::9 .~ "0",

QJ

..5~ t,;:; =m <t:

>. "0 "0

'" ..!!l Cl..'!l t:: '15 QJ m S

';:: "0 QJ ~ 0. ><

"'-l QJ ... ~ .~ ,;:: "0", ~ t::-u ""'"""S '0 ='"

Cl. <t:

.... t:: s u '" ... ~ "'-l "0

c:I

'" "8 tl ::E

~ t * ......

d l~ r-. I 0 0

~ ~ r-. <.c

~ ~ 0

t ~ ~ LD r-. ~ 0 0 0

t ~ ~ LD d 00 0 ~

0 I I I

= * <.c

~ <.c ... ......

0 0 I I I I

C'l ...... ~ d ...... 0 I

I

I I I

t * * <.c a. ...... ......

~ ~ 0 0 0

+ I I I

= = ~ ~ <.c

~ 2 0 d I I I I

QJ

~ ..0 0. -; .. '" o· mS .. s =:", ~ ~ z,.s ~:i ..,..

C'l'- ~ ~ ..... 8 ~ a. z ~ 0. ~ 0('1) Cz ~ .:; a."O =: -0 ....... -~0.""'8~u-~ ..0 0 ~o =:"8 u ti"; ..0 + tl '" ,.s';:: SOl tiD SZ Ol.~

... S S u _"'~ =: ",::E ~ ~ ~ -'" c:I -t:: "'l -: ...... ~..o ~..... ~o ~ ... ~ - ~

E-< ~ 0 0 ....; ~ M ~

v-0(I0;-t::..o~ 1.~.-4 S..o·~ ",..o.!l!, C~~

0(1 ... V'" t::~~

~;fR SO~ t.:':: 0(1; V~~ j~~ o.a. S..!lI ...... '" g Cm

0(I,.s~

~"'~ 8a.

8.~"""

]0(1~ "0..0 a. ~", ...... ~.- '" u;g..o >.~t:: gm(ii

0(I,.s ~ ~"'f8 Sa. "'''' ...... 8:'::

~ a. ...... ..0 .... '" e '" :.::

0(1

s .... '" 8.

7

ssium are given in Table II (b), In the light of recent literature that variations

in moisture account for considerable changes in the availability of potassium, future correlation work will have to be carried out keeping in view these moisture relationships.

Nitrogen:

As pointed out by FITTS and NELSON (1956),

the increasing awareness of the importance of nitrogen in crop production has led many workers in recent years to evaluate the capacity of soils to supply nitrogen to the crops, RICHARDSON (1952) working at Rothamsted reported that minerali­zable nitrogen produced under standard con· ditions was correlated with responses to nitroge. nous fertilizers and that the relationship was as good as that obtained for phosphate or potash.

Fig. 2. (a) Relation between available 'N' (alkaline KMnO. method) and percent ;yield (paddy).

Fig. 2. (b) Relation between available 'N' (alkaline KMnO. method) and percent yield (wheat),

(99)

Dow

nloa

ded

by [

98.1

62.1

59.1

99]

at 1

0:01

15

Nov

embe

r 20

14

~

8 00

Tab

le

II (

b).

Pot

asli

P

addy

Cro

p

Met

hod

& E

xtra

ctan

t P

ot

cult

ure

Exp

erim

ents

F

ield

E

xper

imen

ts

r V

alue

s al

l In

dia

Red

& l

ater

i tic

I r

Val

ues

acid

I W

est

Coa

st

clay

lao

m s

oils

so

ils

of B

ihar

al

luvi

al s

oils

al

luvi

al

of K

eral

a ac

id s

oils

1.

Mo

rgan

's E

xtra

ctan

t -0

.38

-

0.48

* -0

.64

-0

.22

2.

O. 5

N H

NO

, (l

hr.

sha

king

) -

0.12

-0

.34

-0

.64

-

0.79

**

3.

Neu

tral

am

mo

acet

ate

-0.3

6

-0.

21

-0.6

4

-0.6

4

4.

Exc

hang

ed K

% v

alue

s -

0.97

**

-0.3

0

-0.

81n

-

(Oom

men

195

9)

(Tam

hane

, S

ubbi

ah &

P

. K.

Oo

mm

en 1

957)

----_

.-

Tab

le I

I (c

). C

orre

lati

on c

oeff

icie

nts

of

soil

te

st v

alue

s fo

r av

aila

ble

nutr

ient

s by

var

ious

met

hods

an

d

perc

enta

ge

yiel

d re

spon

se

in

pot

cult

ure

and

fi

eld

expe

rim

ents

on

padd

y an

d w

heat

as

obta

ined

by

vari

ous

wor

kers

in

Indi

a.

Nit

roge

n P

addy

W

hea

t P

ot

cult

ure Expe~i!!len~1

Fie

ld E

xper

imen

ts

All

Ind

ia

\ D

hr

'Is

I D

Ih

' '1

I D

elhi

Pot

cul

ture

Exp

erim

ents

F

ield

Exp

erim

ents

Red

and

I In

do

Gan

geti

c A

ll I

ndia

--I

All

In

dia

soi l

s e

I S

Ol

e I

SO

l S

vill

ages

tt

late

riti

c al

luv.

soi

ls

soil

s so

ils

soil

st

(I

expt

.)

(II

expt

.)

1.

Alk

alin

e pe

rman

gana

te m

etho

d

2.

Rap

id I

owa

nitr

ific

atio

n m

etho

d

3.

Sta

ndar

d In

cuba

tion

m

etho

d

4.

Tot

al N

* S

igni

fica

nt a

t 5%

lev

el.

**

Sig

nifi

cant

at

1 % le

vel.

-0.

70**

-0.

48*

lB. V

. S

ubbi

ah

& J

.C.

Baj

aj 1

956)

-0.

86**

-

0.52

**

0.67

* -0

.27

0.81

**

-0.

57**

(Tam

hane

(B

. V

. &

Baj

aj

Sub

biah

&

1959

) S

inha

195

4)

-0.

47**

0.

88**

0.

87**

0.

80*

-0.2

4

0.70

* 0.

75**

-

0.Q

l

0.64

* 0.

77**

0.

47

0.43

0.

43

0.17

(Sub

biah

(T

amha

ne,

(Sub

biah

(S

ubbi

ah

&

Baj

aj)

Sub

biah

&

&

Kal

band

e &

B

ajaj

B

ajaj

195

9)

1958

) 19

56)

t N

egat

ive

high

cor

rela

tion

coe

ffic

ient

s re

fer

to %

yie

ld r

espo

nses

and

pos

itiv

e co

rrel

atio

n co

effi

cien

ts t

o p

erce

ntag

e yi

eld.

tt

R

efer

to

Baj

ar C

rop.

0.84

*

-0.

87*

f" :<: ~ E::

:I:

>

Z

M ~ I:' !J' :<: Ul c gl ;; :I:

Dow

nloa

ded

by [

98.1

62.1

59.1

99]

at 1

0:01

15

Nov

embe

r 20

14

(J:)

.... o .t:;

Tab

le I

II.

All

Ind

ia s

oil

test

sum

mar

ies

and

nutr

ient

ind

ex v

alue

s (s

tate

wis

e) u

pto

31st

Mar

ch,

1959

.

I A

vail

able

P%

lev

els

Ava

ilab

le K

% l

evel

s A

vail

able

N%

lev

els

I S

tate

I I

i Nut

rien

t N

o. o

f I

I

I I N

utri

ent

No.

of

! I

i I N

o: o

f I

I I N

utri

ent

L M

H

L

I M

H

L

I M

I

H

sOlis

in

dex

soil

s I

I in

dex

I so

ils

I i

I in

dex

I I

I i

I

An

dh

ra

i 80

81

52.9

22

.9

24.2

1.

71

2840

I

20.7

55

.1

24.2

2.

03

No

t av

aila

ble

Bih

ar

I 21

62

43.3

33

.3

23.4

!.E

O

191

36.1

35

.5

8.4

1.72

67

5 I

64.4

I

35.6

I

0.0

I 1.

36

I

I B

omba

y 61

36

37.9

41

.7

20.4

1.

83

2313

9.

7 49

.3

41.0

2.

31

4770

I

88.9

i

10.8

0.

3 1.

11

I

Del

lii

4775

28

.0

40.6

31

.4

2.03

25

65

28.2

56

.0

15.8

1.

88

Not

ava

ilab

le

H.

P.

4062

2.

2 14

.0

83.8

2.

82

4072

13

.9

55.4

30

.7

2.17

40

56

32.2

I

62.1

5.

7 !

1.74

I

Ker

ala

4979

73

.7

15.3

11

.0

1.37

49

79

84.8

12

.7

2.5

1.18

I

4979

4.

4 42

.8

52.8

2.

48

Mad

ras

7546

58

.9

25.8

15

.3

1.56

66

26

3.4

22.1

74

.5

2.71

77

02

78.0

21

.0

1.0

1.23

M.

P.

I 44

95

24.9

33

.6

41.5

2.

16

1796

0

10.0

90

.0

2.90

44

96

97.7

1.

5 0.

8 1.

03

i M

yso

re

I 29

83

66.8

24

.0

9.2

1.42

29

83

28.1

38

.9

33.0

2.

05

1199

21

.7

70.8

8.

3 1.

87

Ori

ssa

2329

34

.4

41.4

24

.2

1.90

91

7 2.

3 29

.9

67.8

2.

66

I N

ot a

vail

able

Pu

nja

b

5744

29

.1

41.9

29

.9

2.0

2038

28

.2

50.0

21

.8

1.94

50

69

I 92

.7

6.4

0.9

1.08

I

W.

Ben

gal

2674

7.

4 32

.0

60.6

2.

53

984

33.0

50

.9

16.1

1.

83

2674

60

.4

38.1

1.

5 1.

41

Co

mm

un

ity

18

15

26.8

40

.4

32.8

2.

06

1721

39

.6

51.3

9.

1 1.

70

1492

63

.9

30.8

5.

3 1.

31

Pro

ject

Are

as

5779

1 40

.4

30.3

29

.3

1.89

34

015

26.6

37

.1

36.3

2.

10

3711

2 65

.0

26.2

8.

8 1.

44

_ ..

_.-

--_

.-

Exp

lana

tion

for

nut

rien

t in

dex

val

ues

: T

he

nutr

ient

in

dex

valu

es

repr

esen

t th

e nu

trie

nt

stat

us

of

the

who

le

area

as

a

sing

le

valu

e fo

r

com

pari

ng t

he

fert

ilit

y st

atus

. A

va

lue

of

1 re

s pre

sent

s lo

w s

tatu

s, 2

rep

rese

nts

med

ium

an

d 3

rep

rese

nts

high

sta

tus.

Lim

its

use

d:

(in

Ibs/

acre

)

L M

H

Pho

spha

te

20

50

abov

e 50

Pot

ash

Nit

roge

n 10

0 25

0

250

500

abov

e 25

0 ab

ove

500

(") o :;0

:;0

tIl r ;J>

--l (5

Z o '"

Ij

(fJ

Q

r --l

tIl

(fJ Ul ~ =i :r::

'tl ~ ;J>

Z o :::l

tIl r C

--l

:;0 ;; 1;; - Z --l :r:: tIl

tIl <

;J>

r c:: ~ (5

Z

Dow

nloa

ded

by [

98.1

62.1

59.1

99]

at 1

0:01

15

Nov

embe

r 20

14

R. V. TAMHANE AND B. V. SUBBIAH

The incubation methods recently proposed by STANFORD and HANWAY (1955) could be useful for arable soils but in rice soils, nitrification could hardly be an index of the availability of nitrogen.

The nitrogen availability in India, was evaluated in the past on the bases of total nitrogen values. As Indian soils were very poor in carbon and nitrogen, a value of less than 0.03% of nitrogen

", '-oJ , ... .., .... , .. ... ..

........ U f·

""? -.,: OJ

." D ,/l . - , .... I • ,j

~

." , . ! .....

• A)

.'.

was taken as poor, 0.03 to 0.06 as fair, 0.06 to 0.1 as good and above 0.1 as rich.

In recent years, attempts were made to charaC' terize the nature and decomposibility of organiC nitrogen by using alkaline permanganate as the reagent. The method developed for the assess­ment of available nitrogen involves the use of 0.32% KMnO. and 2.5% alkali (SUBBIAH and

AVAIL A. I PHO"HOAUI "Af U' 0' IND A IIOIL.

'. , . , ....... -. •••• or '.,

~V'RY ,­~ ........ ....

"

, .' " . , . . ....... ;' ; ....... .

. " .... . : ..... ~ ,e,..;

.i

H~H 0

p",~_ ',It T. ",.,A. ,.,., .~. J •• 10

I , 1'/111 /,/lIInt tlltll II InJwn till.

(102) 10

Dow

nloa

ded

by [

98.1

62.1

59.1

99]

at 1

0:01

15

Nov

embe

r 20

14

COI{RELATION OF SOIL TESTS WITH POT AND FIELD TRIALS IN THE EVALUATION

J\SIJA 1956). The available nitrogen values by ~his method correlated well with the total mineral­lzable nitrogen obtained by standard incubation Illethods and also with paddy and wheat yield responses. In Table II (c) is given correlations obtained in different soils of India between avail­able nitrogen by different methods and paddy and wheat crop responses to nitrogen. The alkaline Perillanganate method has shown good correla-

IIQ.Qf tAU.I

N. 11,4" It • II, ••• • • 17.4 .. C • 10.11.

ItH ••• ,'"

tions. This was further confirmed by TAMHANE, SUBBIAH and BAJA.] (1959) who showed that high correlations could be obtained by this method and paddy crop responses in all India soils (vide Fig. 2).

Recent studies conducted by SUBBIAH and BAJA] (1958) showed that in rice soils the am­monia release under water logged conditions after a week's incubation may be a better index of

BROAD lOlL GROU~

t III .LACK tOlLI

~ l2!l,!,

M • ~."O JI! .. 1.11. Ie .. '.Olt C • J •• U ~H. I.a ..

a Illilll RID AND LATUITIC lOlLS OP IAiTIlIM' IMIIIA

I ~ AUUVIAL IOn ••

.. ~ HILLY IOIIaI

I ~ AID AND LA"RITIC IOILI 0' IOUTH IMDIA

Fig. 4. Amilable nutrient status broad soil groups 0/ Indian Soils

11 (103)

Dow

nloa

ded

by [

98.1

62.1

59.1

99]

at 1

0:01

15

Nov

embe

r 20

14

R. V. T AMHANE AND B. V. SUBBIAH

nitrogen availability than the available nitrogen values obtained by other methods. However, this method will require careful standardization because of the possible losses of ammonia in certain soils during incubation.

Soil fertility trends of Indian soils as revealed by soil tests

During the first three years of working about 1.0 lakh of soil samples were analyzed. Soil test summaried (vide table III) and soil fertility maps prepared out of this data have shown almost universal need for nitrogen; nearly 50-75% of the soils were deficient in phosphorus (vide Fig. 3), and 35% were deficient in potash. The % of samples tested low in available phosphorus were high in Southern States of India (KERALA, My­SORE, MADRAS and ANDHRA Pradesh). In these States phosphate applications will be more bene­ficial than in other States. Similarly the percen­tage of samples testing low in potassium was

high in the State of Kerala, Bihar and West Bengal. For nitrogen and organic carbon, the majority of soils tested low. The pH data indio cate that 17.5% soils are acidic-requiring lime practices for improving the crop production while 3.6% are alkaline soils requiring reclamation

measures. £ A map (Fig. 4) showing the nutrient statuS 0

broad soil groups in India, namely, Black soils, red soils and lateritic soils of Eastern India, 801·

luvial soils, hilly soils and red and lateritic soil.s of South India, prepared on the basis of the 5011

tests indicated that, in general, the soils of the red and laterite soils of South India tended to be low in available phosphate and potassium.

Subsoil nutrient availability and its effect oil correlations

The subsoils hold practically unlimited reserves of plant nutrients (BRADFORD 1946) and its effec· tive exploitation will go a long way in meeting

Fig. S. Fluctuation in available nutn·ents in croppzd, and uncroped Delhi alluvial soil with and without fertilization

(104) 12

Dow

nloa

ded

by [

98.1

62.1

59.1

99]

at 1

0:01

15

Nov

embe

r 20

14

CORRELATION OF SOIL TESTS WITH POT AND FIELD TRIALS IN THE EVALUATION

~he increased nutrient requirements of high yield­Ing varieties being developed as a result of recent advances in plant breeding work. Moreover, ~ubsoils fertility becomes significant to the grow­Ing plants after the roots have extended into subsoil layers. Seatz quoted by NELSON et al (1953) attributed the la~k of response of corn due to high amounts of available phosphorus in sub­;Oils. MENDOCK and EGELBERT (1958) found rorn the uptake of radioactive phosphorus that

the subsoil phosphorus as determined by BRAY's rnethod was highly correlated with the fertilizer phosphorus uptake and A values.

Recent work carried out by SUBBIAH and ~JANEYULU (1959) in certain sugar cane soils in ndia showed that the subsoil availability of cer­

tain nutrients may be considerable and may ex­plain the lack of response in certain soils although the surface soils may be poor in the nutrient.

If a close correlation between subsoil and the surface soil nutrient values exists, the need to ~ake a soil sample may not be very essential for b eVeloping correlations between soil test values ased on the surface values alone and crop re­

sPonses. The correlations coefficients between sUrface soil and subsoil values for different nu­;rients obtained by SUBBIAH and ANJANEYULU 1959) are given below:-hit is clear from this table that except for phos­

Porus the other nutrients have practically little Or no correlation between the surface soil values ~nd subsoil values and it will be desirable to take Into account the subsoil values of nitrogen and Potassium for evaluating the soil test-crop re­sPonse correlations.

Ilvailability of nutrients in dIfferent times of the year and finding the best time of soil sampling

d In India, extreme changes in the temperature ~ring the summer and winter seasons, coupled

\Vlth v .. . h· d· . d arIatlOns III t e mOIsture con ItlOns an Inicrob· 1 .. b· b ·d fl . . la actIvIty rIng a out WI e uctuatlOns In the availablity of nutrients during different seasons of the year.

. Fig. 5 shows the fluctuations in available results ~. cropped and uncropped Delhi soil with and

Ithout fertilizations both in the surface and Subs ·1 1 t 01 ayers (SUBBIAH & UMER 1958). The brend of fluctuation is more or less the same in Oth the layers.

13

Generally during the summer months, the soils tend to have highest available values and mini­mum values during the month of February.

From similar studies conducted in relation to correlation of soil test values analyzed at different times of the year and crop yields, the best time of soil sampling for assessing the fertilizer re­quirement was found to be just before sowing for phosphate and nitrogen and for the potash at the harvest time of the previous crop.

Interpreting the experience of the farmers and pooling the follow-up information

The follow-up after the fertilizer recommenda­tions are implemented in the fields gives valuable information on the successful working of the soil test predictions. A few cases of follow-up of recommendations based on soil tests, showing the reliability, usefulness of soil test procedures as practised in this country were studied and it was evident that soil tests, properly conducted and interpreted do supply reliable and practical infor­mation on the fertility status of soils and also any change thereof either due to soil management practices or subsequent fertilizer use which should form the basis for any efficient and judicious fertilizer use in India.

Future line of work The basis of soil testing is that if sufficient

experiments are conducted for knowing the re­sponses of certain soil types to fertilization, and how this is related to the soil test values, then only soil testing can be used to provide a short cut for making fertilizer recommendations. The purpose of fertilizer research should be an at­tempt to obtain a relatively precise indication of the amount of each type of fertilizer needed to get maximum net returns under given price and cost conditions. For determining the optimum levels of fertilizer applications, the requirement will be to obtain response curves and get a single generalized response function for each soil type which could then be fitted to soil test data. The following consideration should l:e taken into ac­count in this type of approach according to LoNG. (1960).

1. Since the fertility originally in the soil is substituted for applied fertilizers, something must be known about the base level of the fertility of the soil upon which experiments are made and this should be answered by soil test.

11M\

Dow

nloa

ded

by [

98.1

62.1

59.1

99]

at 1

0:01

15

Nov

embe

r 20

14

R V. TAMHANE AND B. V. SUBBIAH

2. There should by enough data which should be spread out along a wide range of fertilizer experiments to learn the shape of the function determining the crop responses to fertilizers in each soil type.

3. Since the same responses can sometimes be obtained by substituting one nutrient by the other, it is necessary to learn the nature of their interrelationshiprs. Complex N, P and possibly K experiments need to be conducted to answer this question. The data obtained this way will be very helpful in rendering an economic dose for getting a certain yield by substituting costly fertilizer with a cheaper one if possible.

This type of detailed correlation work is nec­essary for each region and for each crop so as to build good fertilizer recommendations on the basis of soil tests.

Summary

On the basis of preliminary soil test-crop re­sponse correlation work carried out on the basis of the pot culture and field experiments on all India soils, OLSEN's method for neutral to alka­line soils (pH 6.5 or above), and TRUCX:;'s and BRAY's methods for acid so;Js below 6.5 were found to be suitable. For potassium no single method gave good correlation with all India soils. For nitrogen, alkaline permanganate method gave best correlations with the rice and wheat crop responses.

The phosphorus status of the surface and subsoil layers was found to be correlated in some of the soils studied but with respect to nitrogen and potassium, this correlation was either little or nil. Thus it wi1l be desirable to take into account the subsoil values of nitrogen and potas­sium separately for evaluating the soil test-crop correlations with respect to these two nutrients.

The best time of soil sampling for assessing the fertilizer requirement was found to be just before sowing for phosphate and nitrogen and for the potash at the harvest time of the previous crop.

The need for detailed correlation work for each region and for each crop has been stressed for building up sound fertilizer recommendations on

(106) 14

the basis of soil tests in India.

References

1) BRADFIELD, R, Soil Sc. Soc. Amer. Proc. 11, 3~ 8 (1946).

2) DAS, 5., Ind. Dept. Agric. Mn. Ch. Series 8, 69~ 104 (1926).

3) DATTA, N. P. & KAMATH, M. B., Research Rport No.1, IARI (in press) (1938).

4) FITTS, J. W. & NELSON, W. L., Advances in Ag' ronomy, 8, 242 (1956).

5) LEATHER, Mem. of Deptt. of Agri. Ind. CheJll· Series 1, 45-47 (1907). '1

6) LONG, E. J., Paper presented to the Annual 501

Testing Conference, IARI (1960). 7) MUKHERJEE, H. N., MANDAL, S. C. & MUKHERJEE,

O. P., Proc. Bihar Acad. Agri. Sci. 4, 140 (1955) .. / 8) MENDOCK, J. T. & EGELBERT, L. E., Proc. SOl

Sci. Soc. Amer. 22, 53-57 (1958). 9) NELSON, W. L., et al., Amer. Soc. Agron. J. MollO.

4, 153-84 (1953). 10) OLSEN, S. R, U. S. D. A. Circular, 939 (1954). 11) OOMMEN, P. K, pH. thesis, Bombay UniversitY,

(1959). 12) RAYCHAUDHURI, S. P., SUBBIAH, B. V. & SINI-lt\,

M. P., Proc. Sci. Congress, India (1954). 13) RICHARDSON, H. L., Int. Soc. Soil Sci. TranSilC'

lions, II, 28 (1952). 14) SAHASRABUDHE, Deptt. of Agric. Bombay BIIIl.

16 (1929). , 15) SEN, A. T., DEB and BOSE, Soil Sci. 68, 291-30~

(1940). 16) STANFORD, G. & HANWAY, J., Proc. Soil Sci. SoC.

.. 4mer. 19, 74-77 (1955). 5 17) SUBBIAH, B. V. & ASIJA, G. L., Curro Sci. 25, 29

-60 (1956). . d 18) SUBBIAH, B. V. & Anjaneyulu, B.S.R, Unpubhshe

work (1959). k 19) SUBBIAH, B. V. & BAJA], J. C., Unpublished wor

(1956). 20) SUBBIAH, B. V. & KALBANDE, A. R, Unpublished

work (1958). 21) SUBBIAH, B. V. & UMAR, Unpublished work (195B~ 22) TAMHANE, R V. & KOLARKAR, A.S., Unpublishe

work (1959). 23) TAMHANE, R V. & SAOLAPURKAR, V. K, Unpub'

lished work (1958). 24) TAMHANE, B. V., SUBBIAH, B. V. & BAJAJ, J. C·,

Unpublished work (1959).

) 0 N 1'. 25 TAMI-IANE, B. V., SUBBIAH, B. V. & OMME, C K, Proc. of Board of Crops & Soils Wing, J .. AR. (1957).

Dow

nloa

ded

by [

98.1

62.1

59.1

99]

at 1

0:01

15

Nov

embe

r 20

14