HYV and Fertilizers - Synergy or Substitution. Implications for Policy and Prospects for Agricultural Development

HYV AND FERTILIZERS--f.YN~RGY

OR SUBSTITUTION. IMPLICATIONS FOR POLICY AND PROSPECTS FOR AGRICULTURAL DEVELOP~£NT

K. S. Parikh

June 1980 PP-80-4

ProfessionaZ Papers do not report on work of the

International Institute for Applied Systems Analysis, but are produced and distributed by the Institute as an aid to staff members in furthering their profes- sional activities. Views or opinions expressed are those of the author(s) and should not be interpreted as representing the view of either the Institute or its National Member Organizations.

INTERNATIONAL INSTITUTE FOR APPLIED SYSTEMS ANALYSIS A-2361 Laxenburg, Austria

P~F~E

Food production is one of the most complex and many-sided activities of mankind, and involves coordination of biological, technical, environmental and economic factors. To understand the operation of these rather complex systems, i t is necessary to make a study of the elements of the system. Kirit Parikh's paper deals with a very important problem: that is the effi- ciency of fertilizer usage on high-yielding crop varieties as well as the related consequences. The work, as reported in

this paper, is a preliminary step toward the development of IIASA's Indian Agricultural Model; its results were used exten- sively in the IIASA work.

-iii~

SUMMARY

The conventional wisdom regarding the nature of the yielding varieties (HYV) which have ushered in the "Green Revolution" includes the following beliefs:

1. The HYV's give higher response to fertilizers than the

"local" varieties.

2. The HYV's need fertilizer and irrigation for realizing their higher responses.

3. The HYV's respond synergistically to a package of inputs and practices, the most important among the

inputs being the three fertilizers--nitrogen, phosphorus and potash--and irrigation.

The policy implications of these beliefs are obvious:

1. It is more efficient to allocate fertilizer to HYV's than to "local" varieties.

2. HYV's should be adopted only when assured water and fertilizers are available.

3. Since inputs act synergistically, i t is more efficient to concentrate the developmental efforts in selected areas for promoting intensive agriculture.

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the nature of the HYV technology at least at the low level of inputs used by the Indian farmers and consequently questions the policy implications of that conventional view.

Based on the data from more than 15,000 trials carried out on farmers' fields by the Indian Council of Agricultural Research, i t is shown that the yield response functions are such that

the best HYV for the zone dominates the local variety and gives higher yield even without fertilizer. It is also found that

for some cases the yield response to fertilizer of a local variety is higher than the yield response of the HYV. The paper also

argues that i t is not easy to reject the hypothesis that the data from the simple fertilizer trials are representative of Indian farms.

The paper also presents in an appendix the estimated yield response of the dominant varieties for

8

major crops of India for different agro-climatic zones along with their plots.

-vi-

CONTENTS

Introduction, 1

The Analysis and the Nature of the Response Functions, 3 How Reliable are SFT Results? 7

Prospect for Agricultural Development, 9 Notes, 11

Appendix: Yield Responses of Different Crop Varieties in Different Agro-climatic Zones, 13

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HYV AND FERTILIZERS--SYNERGY OR SUBSTITUTION IMPLICATIONS FOR POLICY AND PROSPECTS FOR AGRICULTURAL DEVELOPMENT*

Kirit S. Parikh

INTRODUCTION

The conventional wisdom regarding the nature of the high yielding varieties (HYV) which have ushered in the "Green Revolution" includes the following beliefs:

1. The HYV's give higher response to fertilizers than the

"local" varieties.

2 . . The HYV's need fertilizer and irrigation for realizing their higher responses.

3. The HYV's respond synergistically to a package of inputs and practices, the most important among 'the

inputs being the three fertilizers--nitrogen, phosphorus and potash-- and irrigation.

The policy implications of these beliefs are obvious:

1. It is more efficient to allocate fertilizer to HYV's than to "local" varieties.

2. HYV's should be adopted only when assured water and fertilizers are available.

3. Since inputs act synergistically, i t is more efficient to concentrate the developmental efforts in selected areas for promoting intensive agriculture.

*

This paper, with the exception of the Appendix, was published in the "Economic and Political Weekly", Review of Agriculture, March, 1978, Bombay.

kgjHa

I

(a)

Variety

Local Variety

(Fertilizer) kg/Ha

of Irrig.& Fert.

Unirrigated

F

(b)

o HYV gives higher yields than local only with fertilizer

o HYV has a higher response[

~ ~

⁾

to fertilizer \

o Synergistic response to fertilizers and irrigation

f j , y . > fj,y + fj,y .

(Irr1g.& Fert)- Fert. Irr1g.

o Better to put fertilizer on irrigated HYV

Y HYV

Local

Y

HYV

Local

F

(c)

o HYV is dominant and gives higher yield even without fertilizer o And, HYV has a higher response

to fertilizer

F

(d)

o HYV dominates local variety. However local has a higher response to

fertilizer

o Given that both HYV and local

are cultivated, fertilizer should be put first on local variety.

Fig. 1 Implications of Different Types of Yield Responses.

-3-

However, the extensive analysis of yield responses to fertilizer that was carried out by Parikh, Srinivasan et ale

(1974}1 (henceforth referred to as PS study) does not seem to support the conventional wisdom·regarding the nature of the HYV technology at least at the· low level of inputs used by

Indian farmers and consequently

qu~stions

the policy implications described above. The implications of different types of yield responses are summarized

in

Figure 1*, where 1 (a) and 1 (b)

correspond to the conventional view described above. In Figure 1 (b), the dotted line shows a line obtained by shifting vert- ically, by an amount equal to the increase

in

base yield due to irrigation, the response line for unirrigated HYV. The dotted line thus, represents what would have been the response function for irrigated HYV if there were no interaction between irrigation and fertilizer. From our analysis, however, it is argued that the yield response functions are certainly such that the HYV's are dominant as shown

in

Figures 1 (c) and 1 (d); for some cases the slope of the response functions may be more like case 1 (d) than like 1 (c).

Before turning to the results of our analysis i t would be useful to briefly summarize the data collected and the analysis carried out.

THE DATA

The Indian Council of Agricultural Research (ICAR) has had for many years extensive programmes of development of HYV of various crops, as well as for evaluating the yield responses of these and local varieties under different inputs and culti- vation practices. For the purpose of evaluating the yield res- ponses to fertilizers, two sets of experiments are particularly important. One set, called the Model Agronomic Experiments

(MAE), comprises of experiments carried out on farms of the research stations where complete control is exercised by the researchers. The other set, known as the Simple Fertilizer Trials (SFT), is carried out on cultivators' fields. The main objective of the programme is to determine the fertilizer

requirements of the new high yielding varieties and to compare their performance

(in

cultivators' fields) with the perfor- mance of locally improved varieties under different soil and agro-climatic conditions

in

the country. The SFT's are exten- sive and cover many different districts and crops.

* The responses shown

in

Figure 1 are not the only possible

response types--but they cover the points that are being

argued

in

this paper.

Though we had also analysed most of the relevant MAE

performed to the year 1969-1970 in research stations, we relied on the results of the Simple Fertilizer Trials (SFT) carried out on farmers' fields up to the year 1970-71 as they were more relevant and extensive. We had data from nearly 31,000 8FT's carried out over the period 1965-66 to 1970-71, of which 15,000 trials were carried out over the years 1968-69 to 1970-71.

For a given crop, the districts for the SFT's are selec- ted randomly (at least in theory). In the field of the selected cultivator, subplots of specified size, (usually around 40 to 50 sq. meters) are laid out, on each of which the cultivator is supposed to sow the given seeds and apply the fertilizer treatments as specified by the researchers. Only the variety and rate of seeds and the quantities of chemical fertilizers are controlled. The cultivator is free to determine all other inputs and practices. The yields in each subplot are separately recorded.

We stratified the data by agro-climatic zones. These zones are shown in appendix Figure A.1. Within a zone, the trials were further stratified merely as irrigated and un- irrigated trials because adequate information on the amount of irrigation was not available. For a specific combination of crop var~ety,agro-climaticzone and water regime, the data were pooled together to estimate the yield response functions separately for different years as well as with pooled data for all the years.

THE ANALYSIS AND THE NATURE OF THE RESPONSE FUNCTIONS For all the model agronomic experiments and the SFT

data for the years 1965-66 to 1969-70, three quadratic response functions were estimated through multiple regression with

variables as shown below:

2 2 2

Y = feN, N , P, P , K, K , NP, PK, NK, NPK) , Y = Yield in kg/ha

N, P, and K stand for the levels of N, P and K respectively, in kg/ha. NP, PK, NK and NPK stand for the products of the levels of fertilizers applied.

Note that in these regressions in addition to the quadratic terms, interaction terms between Nand P, Nand K, P and K and N, P and K are also introduced. Positive and significant

coefficients or interaction terms imply that the nutrients are more efficient when applied together than when applied separately.

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Negative coefficients of the quadratic terms for N2 , p2

, and K2 , would imply diminishing marginal returns to these nutrients, and positive coefficients would imply increasing returns.

In one set of regressions, the intercept representing the base yield was permitted to be different from experiment to experiment to account for variations in soil fertility and culturing practices from farmer to farmer.

In another set of regressions~ the effects of these variations are sought to be taken care of by regressing additional yield

due to applied nutrients against applied nutrients.

It was observed that the set of response functions which did not distinguish between farmers and in which total yield was regressed against fertilizer applied gave better results than the other two and that the interaction terms were not statistically significant in most of the cases for all the three sets of regressions.

Thus the SFT data do not show any significant interaction among Nitrogenous, Phosphoric and Potassic fertilizers as far as their effects on yield are concerned. The incremental yields due to the three fertilizing nutrients can be taken to be additive.

This is not to suggest that one may not find soils in India where the interaction of the different fertilizers would show dramatic synergistic responses. But our results do indicate that in large parts of the country on the land cultivated by farmers such interaction effects are not significant.

The estimated response functions for paddy and irrigated wheat are shown in Figures 2 and 3 respectively for typical

zones. The different curves in a figure refer to different varieties. These figures are typical of almost all the zones and crops for which we had comparable data as can be seen in the appendix where the detailed estimates and plots are given.

Two important observations may be made from these figures:

1. There is one variety which dominates all'others in the sense that i t gives a higher yield than other varieties at a level of fertilizer use which is the same or lower. This is true even when no fertilizer is applied.

2. The slope of the yield response function of the dominant variety is not necessarily larger than the slopes of other varieties.

These observations imply that a cultivator may be able to get a larger yield from a high yielding variety even without applying any fertilizer.

3975

3555~..:::::::::~---

i

&2464 ...-~~

:!

15 30 45 60 75 90 105120 Potash used (kgs per hecure'

14521<::.._.."."..----:'::----:'="""'"=:':"""-:!'::"~:"":':!o 15 30 45 SO 75 90 105 120 Phosphorus used (kgs per hectaro)

Fig. 2 Yields of different varieties of paddy (Zone-7L+c)

4130 3692

i

³²⁵⁴

.c

~ 2154

>

used

2207

~

1972

1 7 3 7 @ 1 5 0 2 _ 90 lC5 120 0 15 30 45 60 75 90 105120 Phosphorus used (kgs per hectarel Potash used (kg, per hectare;

Fig. 3 Yields of different varieties of irrigated wheat (Zone-4A)

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Thus a farmer need not be advised to ensure his fertilizer supply before planting HYV seeds.

Typically, however, agronomists react to this conclusion as follows: HYV's give a higher yield and therefore they must take out more nutrients from the soil. Consquently, the yield next year would be lower unless the fertilizers are applied.

A number of comments need to be made on such a reaction.

1. An HYV may give higher yield of grains but may not produce higher bio-mass of the total plant matter.

The nutrients removed "from the soil should depend on the total plant matter produced.

2. Even if an HYV does deplete the soil when no fertilizer is applied leading to a risk of lower yield in subsequent seasons², the new possibility opened up by recognizing that farmers can get the benefits of HYV at least in the first year, even without fertilizers, should be appreciated. It becomes possible for a cultivator to adopt an

HYV this year and from the extra revenue of the extra yield buy the fertilizer before the next season.

3. If the agronomists' claim is correct, that HYV depletes the soil unless fertilizer is apglied, then the yield response functions required for policy guidance have to be based on trials carried out over a number of seasons on the same plot. Thus the yield response functions obtained from the SFT's are not useful for policy guidance. One wonders why then have we spent so much effort and resources for carrying out these SFT's.

By itself, the fact we have established so far, that the dominant HYV gives a higher yield even without fertilizer than other HYV's is not enough to fully question the view implicit in Figure 1 (a) and (b). It may still be possible that a local variety gives a higher yield than the HYV when no fertilizer is applied (Figure 1 (a» or that a complemtarity effect is present.

To examine the issues of complementarity of inputs one would like to compare the yield responses of the best HYV

against the best local variety under irrigated and un irrigated cultivation in the same agro-climatic zone. Unfortunately, the data we have analysed do not contain such tests. None- theless, a number of pairwise comparisons are possible. Tables 1 and 2 show the base yields for wheat and rice (i.e., yields without any fertilizer applied) for some zones. Also shown in these tables are the "optimum" dosages of fertilizer in the reference case of the PS study.

Table 1. ·OptimWII·· fertilizer dosaqe. - ICq/Bectare Wheat - Reterence Case.

Irrigated Base Yield^il "Optimum"

•

Fertilizer

Zone or not Variety (Rg/Ha) Dosages r.g/Ha

N p J(

IIA 11 Irrigated BYV(5) 21179 87.5 51.4 0

Unirrigated BYV(34) 11102 (120.0) 0 (60.0 )

8SM1 Irrigated BYV 1632 35.3 0 (60.0 )

Unirrigated HYV 1088 0 8.1 0

3MB12 Ir~igated BYV 11155 38.0 27.6 31.8

Unirrigated BYV 555 0 (30.0) (30.0)

6MB Irrigated BYV 14911 (60.0) 29.6 (30.0 )

Onirrigated BYV 588 0 (25.0) (25.0 )

IIRB1 Irrigated BYV 16111 0 0 0

Unirrigated BYV ^1l1li8 (120.0) 0 119.6

3A21 Irrigated BYV 2326 611.7 32.6 29.9

Onirrigated BYV 14110 0 25.2 (30.0)

2MB Irriqated HYV 1655 0 311.3 0

·

^{Local 101111 10.9 29.8 (30.0 )}

3GB Irrigated BYV 2669 0 32.0 0

·

^{Local 18112 0 0 18.3}

3MB11 Irrigated BYV 11155 38.0 27.6 31.8

·

^{Local 1389 11.11 19.7 25.8}

3MB12 Irrigated BYV 652 0 22.1 0

• Local 552 0 15.11 0

3RBRY Irrigated BYV 1218 35.1 (30.0 ) 16.9

·

^{Local 1093 0 16.0 21.1}

1IA2 Irrigated BYV 1970 36.5 7.6 32.3

• Local 1397 0 20.1 23.9

IIRB2 Irrigated BYV 16111 0 0 0

• Local 1375 0 0 34.3

5A2 Irrigated BYV 20119 '60.0) (30.0) (30.0)

Unirrigated Local 1329 0 17.0 26.6

6BR Unirrigated HYV 1233 0 0 ( 60 . 0)

Unirrigated Local 9113 0 0 0

•

Having the same marginal physical product, excepting number in ()'s which are bound by the maximum dosages tried in the SFT's and so have higher marginal physical products.

il Yield without any fertilizer.

Table2.

*

"Optimum"fertilizerdosages-kg/Hectare PaddY-ReferenceCase

.

BaseYield@

*

ZoneIrrigatedVariety"OptimumII FertilizerDosages UnirrigatedHYV/LocalKg/HectareKg/Hectareofnutrients NpK

---_

.•.-....-......__.._----_. 4A3IrrigatedHYV2554(60)(30)(30) IrrigatedLocal1886(60)(30)(30) 4MB1IrrigatedHYV309757.625.333.4 IrrigatedLocal2413(120)(60)0 4A2IrrigatedHYV1915(120)(60)0 IrrigatedLocal1548(120)44.957.1 7LCAUnirrigatedHYV3759(120)(60)36.2 UnirrigatedLocal152400(60) 5DBUnirrigatedHYV137700(30) UnirrigatedLocal8980(30)(30)

*

Havingthesamemarginalphysicalproduct,exceptingnumbersin()'swhichare boundbythemaximumdosagestriedintheSFT'sandsohavehighermarginal physicalproducts. @Yieldwithoutanyfertilizer

I \D I

The reference case involved computation of the minimum total value of fertilizer (N, P, and K) required to meet the output targets of the five year plan given the relative prices of the fertilizers and the area under HYV as per the plan targets.

(For details see ref.1).

At these dosages all the varieties give the same marginal physical product for a unit of fertilizer, excepting when the dosage of fertilizer is at the upper limit of the permitted dosage, in which case the marginal physical product is higher.

Limits on fertilizer dosages were imposed so as not to extra- polate responses outside the range of dosages applied in the 8FT's.

The nine zones for wheat and the five zones of paddy for which responses for HYV and local varieties are available from 8FT's, the base yield of the HYV is higher than the yield of the local variety in the same zone. This is true also of the unirrigated cultivation for which responses are available for three zones. Thus the HYV does dominate the local variety even at zero fertilizer level.

The base yields of the irrigated HYV's of wheat are also higher when compared with the base yields of the unirrigated HYV's for the 6 zones in Table 1 for which comparable responses are available from 8FT's.

However, whether the improvement in the yield of irrigated HYV over yield of unirrigated HYV is more than the improvement in the yield of irrigated local variety over yield of un-

irrigated local variety cannot be established (or disestablished) for want of comparable data.

A comparison of the "optimal" dosages in Tables 1 and 2 can give us some idea about the extent of complementarity

between fertilizer and irrigation and between HYV and fertilizers.

If fertilizers and irrigation are complementary inputs for HYV's then the "optimal" dosages of fertilizers for irri-

gated HYV should be higher than those for unirrigatea-HYV.

The first six zones in Table 1 do not show this to be the case unambiguously. For nitrogen, the yield response is better

fo~ unirrigated HYV for 2 out of 6 cases. Both for P20S and K2

0

the unirrigated HYV response is better for 2 cases and nearly equal for 3 cases out of a total of 6 cases.

If fertilizers and HYV's are complementary, then we could expect to see that "optimal" fertilizer dosages would be higher for HYV's than for the local varieties. We see that of the 14 zones (9 for wheat and 5 for paddy) giving 42 fertilizer

dosages, HYV optimal dosages are larger for 18 cases, smaller for 11 cases, and the same as that for the local varieties for

13 cases. Thus once again we see that the complementarity between the HYV and fertilizer cannot be considered to be very dominant.

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The policy implications are that fertilizer need not necessarily be concentrated either on irrigated land or on HYV's. Fertilizer allocation ought to based on an analysis of local conditions and responses of the available varieties.

It should not be guided by general principles of synergy or intensive agricultural development.

HOW RELIABLE ARE SFT RESULTS?

It has been suggested many times that the SFT responses are better than that which could be exoected under conditions of "mass applications^ll3• The statement. implies that in a given zone the cultivators who on their own grow a given high yielding variety for a given level of fertilizers get a lower yield than the yield obtained by the cultivators under the SFT programme growing the same variety for the same level of fertilizers. It is not clear on what basis such a suggestion is made. I do not know of any systematic study which has collected the type of data required for such a comparison⁴•

Nonetheless, one can advance two possible explanations for such a belief. Apart from the point discussed above, namely that of a possible loss of soil fertility when HYV is culti- vated without fertilizers, SFT responses may give better results than the average responses in the zone if the SFT farmers and farms were not representative of the zone as a whole.

In the absence of data perhaps the gross "scale factor"

adjustment (see below) made in the PS study may be as good a way as any to evaluate in broad terms the issue of how re-

presentative are the crop yield response functions obtained from the SFT data.

The model in the PS study calculates the optimum require- ments of fertilizers to produce prescribed amounts of output,

given the areas allocated to the crop in different zones and given the yield response functions in each of the zones.

In order to do so, the PS model was applied to a past year's data to predict the fertilizer required and to compare the predicted data against the actual values.

For this purpose, the year 1970-71 was selected as the latest year which was not unusually bad or good and for which data were available for the statewise total, irrigated and unirrigated areas devoted to the HYV and local varieties of different crops and statewise production of the crops as well as statewise total consumption of N, P20S and K20. 1970-71 was also one of the years on the SFT data of which our response

functions are estimated.

Not having data on cropwise consumption of fertilizers, all the yield response curves were shifted up or down together by the same percentage so that the amount of fertilizer required equalled the amount actually used

in 1970-71 and the estimated

production was equal to the actual.

The ratio of the final adjusted base yield to the base yield estimated from SFT data was called the "scale factor"

for the state.

It should be noted that the "scale factor" merely shifts the yield response up or down without affecting the shape of the response curve. In other words the marginal yields of fertilizers are not affected. There

is some evidence to

suggest that the various agricultural practices, the effects of which are not explicitly taken into account

in our estimated

response function affect

mainly the base yields^5•

The scale factors obtained are shown in Table 3:

Table 3. The "scale factors".

State Name Scale factor

estimated Andhra Pradesh

Assam Bihar Gujarat

Himachal Pradesh Jammu and Kashmir Kerala*

Tamilnadu Karnataka l1aharashtra Madhya Pradesh Huryana

Orissa Punjab Rajasthan Uttar Pradesh West Bengal

.98650 .66756 .60572 1.19980 L 13887 1.08990

.97697 1.19980 .75000 1. 31250 1.07656 .82500 .90015 1.19980 .86250 .67188

* Since large parts of fertilizer consumption

in Kerala is for

plantation for which separate consumption data was not available

to us, we have not attempted to estimate scale factor for the

state.

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A scale factor of 1.0 implies that the yield responses obtained from the SFT data are equal to the average responses of the state. A scale factor larger (smaller) than 1.0

implies that the SFT yields are smaller (larger) than the state averages.

Of the 16 states for which we had calculated the scale factors 7 are greater than 1.0, and 2 more are almost equal to 1 .0. The median value is around 0.98 and the average is 0.96.

One cannot thus rule out that the SFT responses are reasonably representative and that they do not have any particular optimistic bias.

Admittedly, the scale factor adjustment has involved a number of assumptions, and one may not accept this evidence as conclusive for the representativeness of the SFT results.

Even then i t should be emphasized that there is no evidence whatsoever on which one can sav that SFT results are not

reproducible on a large scale.-

PROSPECT FOR AGRICULTURAL DEVELOPMENT

A simple projection based on the SFT data without using any scale factors can indicate the potential for growth of output in Indian Agriculture.

The production potential and the fertilizer required have been worked out⁶ assuming that:

1. all farmers would adopt the dominant variety;

2. the yields in zones in which no SFT's have been carried out would be the average yield in the zones in which SFT's are carried out;

3. the expansion of area under cultivation and irri- gation is restricted to the fifth five-year plan

targetsr{i.e., targets to be achieved by March, 1979).

4. the fertilizer dosages cannot exceed the maximum levels tried in the SFT's;

5. the cropping pattern in an agro-climatic zone remains the same as for the latest years for which data were available, which was for 1967-68 for most of the zones.

These projections are given in Table 4.

Table 4. Prospects for Agricultural Output (in million tonnes) .

Input Requirements of

Crop Actual Prod. Production Nitrogen Phosphorus Potash

for 1974-75* Potential

Rice 40.2 168 5.05 2.47 2.43

Jowar 10.2 38 1.00 0.60 0.50

Bajra 3.2 24 1.00 0.19 0.47

Maize 5.7 22 0.61 0.28 0.32

\'lheat 24.2 73 1.88 0.88 0.82

Cotton 3.6 11 0.67 0.29 0.42

Groundnut 5 12 0.24 0.33 0.27

Gram 4 12 0.26 0.50 0.33

*

Data on cropwise consumption of fertilizer are not available for 1974-75. However, total fertilizer consumption (not just these 8 crops) in the country was 1.77, 0.47 and 0.34 million tonnes of N, P20S, and K20 respectively.

Clearly the technical production potential is very large, and the fertilizer requirements are also moderate.

Of the assumptions made above, two are more important in terms of the policy actions required for the realization of this potential. These are the adoption of the dominant (HYV) varieties by the farmer, and evolution and testing of HYV's

{for the agro-climatic zones for which such varieties have not been tested in the SFT's t i l l the end of 1970-71. Both these require much greater efforts in research and extension than have been made t i l l now, but ought not to pose any diffi- culties in mounting these efforts, particularly once i t is recognized that the new technology provides significant growth potential through an extensive rather than intensive development.

It seems to me that quite a bit of this potential should be realizeable without significant structural changes in the ownership pattern or tenancy structure. This is not to say that reforms in the latter are not desirable or that they may not even increase the adoption rate of new technology. It is merely to emphasize that growth is possible without requiring

as preconditions for growth what today seems to be ~oliticallv

improbable structural reforms.

-15-

NOTES

1. Kirit S. Parikh, T. N. Srinivasan et ale (Dec. 1974) Optimum Requirements of Fertilizers for the Fifth Plan Period.

New Delhi: Indian Statistical Institute and The Fertilizer Association of India.

2. This is a bit surprising as i t is usually claimed that nitrogen is not carried over in the soil from one season to another, and nitrogen is the relatively more important nutrient for Indian soils.

3. A. Vaidyanathan. (Dec. 17, 1977) Constraints on Growth and Policy Options Reply. Economic and Political Weekly

13(51).

4. The NCAER study (Sept. 1974) Fertilizer Use on Selected Crops in India, New Delhi: National Council of Applied Economic Research and The Fertilizer Association of India, is not quite adequate for this purpose, as the fertilizer dosages are reported not statewise but on all India basis and the varieties are not identified in their reports.

However, the results do show that farmers do use fertilizers on irrigated as well as unirrigated and on HYV as well as on local variety cultivations, and thus do recognize the various substitution possibilities.

5. H. van Keulen. (1977) Nitrogen aequirements of Rice with Special Reference to Java. Contributions (30). Bognor

(Indonesia): Central Research Institute for Agriculture.

He argues that the relationship between N-uptake by the plant and N-fertilization given to the soil is linear with some N-uptake even at zero level of N-fertilization and that this intercept represents the inherent soil fertility and is a function of soil characteristics, environmental conditions, and the history of the field, particularly previous crop, fertilizer application and management practices.

6. Kirit S. Parikh. (1976) India in 2001. population, Resources and Environment, edited by Coale, Ansley.

New York: Macmillan.

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APPENDIX: YIELD RESPONSES OF DIFFERENT CROP VARIETIES IN DIFFERENT AGRO-CLIMATIC ZONES

The yield response functions estimated from the simple fertilizer trials, for the different varieties in a zone, were classified into five separate groups as follows:

Group Code 1

2 3

4

5

Description Irrigated HYV Unirrigated HYV Dry Farming Variety

Irrigated "Local" Variety Unirrigated "Local" Variety In each of these groups, the dominant varieties were

identified. In this appendix, we present the yield response functions and their plots for those zones for which varieties from two or more of the above five groups were tried out.

The agro-climatic zones are shown in Figure A.1.

The estimated response functions are shown in the tables A.1 to A.9. Since the interaction terms between Nitrogenous, Potassic and Phosphatic fertilizers were found to be insignifi- cant in most of the regressions, i t is possible to plot the yield response functions separately for the three nutrients.

These plots are given in Figures A.2 to A.10.

It should be noted that in the plots for dosages of

fertilizers that exceed the maximum dosage tried in the experi- ments, the yields are shown to be constant at the value of the yield corresponding to the maximum dosage of fertilizer.

The fertilizers are measured in terms of nutrients.

Figure A.1

. -

. .

.

_".

^,

...~.c':

. . . . _I. . . . .

....&1

Agro-Climatic Zones of India

SRYI 10,-,o~

., l' .!Z!:~

Lit

7A. -..

t.t.,,~I't.

, '.l-'::':'!'~~At.l.""...

!-leA 04 -:!,.',,:a ""L~WI'-"

~&_"(,0.1'".,ae"

00-C!i a Il.J.CM SO - \ ..., ..e~.tJC

G&-GoL' t-10-

o-GULar

A - 'E' R8 - JrO '>.0.~'C.

AY - a(~

".0

,E~~CO'

CS - C.~t~'(>J55'(-:'::114 SM-'",Ive.. rcr...s IH-101':'.", ... ",,,

L - U'ra'-':5.~oU!U"C 1 - ....".

!"!O:'Srl.'~rIAi:1CJt

1_ ...'J

1--10Ie·10

3 - ." ,.~IO

.. - ·ro^t.·40 S - . . . ./0 , -, - _,." • • 'to0I .

I'"

•- ._.·rw

Figure A.2

-19-

Yield ReSDonse of Winter Paddy

3f.21

w- I:ADDY W. PADDY 3A21

50GO 4375 3750 31.2=

2500 1675 1.250 525

a a 20 40 60 60 100 120

IIIITRGGEN (K.G/H.")

T

a 10 20 30 40 50 50 PH05PHGRGUS (KG/HAJ

a 10 20 30 40 50 60

3R81 w- PADDY 3R81 w- PADDY 3R81 w- PADDY

5000 4375 3750 3125 2500 1675 1250 525

a a 20 40 60 60 lCO 120

"lITRGGE.N (KG/HA)

a 10 20 30 4C 50 60 PYOSPHOROUS (KG/HA)

a

10 20 30 40 50 50

o

.... d

>-

5000 4375 3750

250G 1250 525

o

4:'11 W- I:ASOY

a 2C 40 sa sa lCO ~2C

4Al1" w- P.A.ODY

^4f,i.l 'Ii-

I: l,CO

'r'

r ^a

^{1.0I 20II}

:

^{30 .:c\I SO~I}

^~

^liOI

t ^a

^.lou

^.

^{,~ 20 3G ':0 50 50}

Figure A.2 (Contd)

4/.2 w·

^p."GOY

4A2 w·

^p."GOY

^4A2 w·

^P/~OCY

~ SOGO

<'

:I: 4375

,

:..J jlSO

:.::

c 3iC:5

c: c: ^c: c: c: c:

=

...J

- ^-

... 2500 .4

....

^~

...

~ 1575 ,.--"=

1250 ^----4

ScS

^a _a

20 40 50 BO 100 120

a

10 2G 3G 40 50 50

r a

10^I 2G^I 30 40^{I I} SO 60^{I I} NITROGEN (KG/H~) PHOSPHOROUS (KG/HI' ) POTASH (KG/H,",)

4A3 4A3 W. PADDY 4A3 W· PADDY

C...J

....

~

:-

50GO 4375 3750 3125 2500 Hi7S 1250

a a

20 40 60 SO lCO 120

4V511 W·

PADDY

5000

4375

3750 3125 2:00 .:.575 leSO 625

o

o

20 4G ~o 5G LCS 120

"lITRCGEN (KG/Hfd

o

10 20 30 40 50 50

PYGSPHGROUS iKG/HAl

4\i5il

W· PADDY

f

^{I I I I I I}

0 1.0 2() _3C 4G 'jO 50

PHOSPHOROUS lKG/HA)

o

10 20 30 40 SO 50

4M5il W· P.A.COY

t

T

I

t

_II _{I I I I I I} a 10 20 3G 40 SO 50 POHSH (KG/HA)

Figure A.2 (Contd)

4Ri

W· PADDY

-21-

4Ri

W· PADDY

4Ri

W. PADDY

o...J W

....

>-

selJlJ

4375 3750 31.25 2500 1575 1250 625

o o

20 40 60 60 100 120

NITROGEN (KG/HA)

4RCAl W· PADDY

5000 4375 3750 3125 2500 1675 1250 625

o o

^{20 41J 60 50 100 120}

~ITROGEN (KG/HAl

o

^{10 20 30 40 50 50}

PHOSPHOROUS iKG/HAl

4RCAl W·

p ..

\DDY

a

^{10 20 30 40 50 50}

PHGSPHORCUS (~G/HA)

o

^{10 20 30 4C 50 EO}

4RCAl W· CADDY

o

^{1.0 20 30 4C 50 5C}

SAil SAll

50GO 4375 3750 3125 250G 1675 1.'::50 525

o o

^{2G 40 ':0 5C lOG}

leG

_{0 lQ 20 30 40 ":0 50}

t

_a ^{I f '}~V^I _2C^I ₃₀^I ₄₀

^,

_'Sc^I ₆₀^I

POTASH (KG/H.... l

Figure A.2 (Contd)

a

10 20 30 40 50 50

SAc:

-

^:::L

.- .-

'-

-

r- -=-

~

~ '"

<.'

51'.2

PHGSPHGRCUS (KG/HAl

a

10 20 30 40 50 60

5A2

^'N.

P.'\OCY

~ 50a-:

:I:< .:375

"

G 3750

~

0 3125

...J 250a

.... -

^{>- 1615}

1250 525

0 ^I I I

0 20 40 60 60 100 120 NITRGGE!'l (KG/H .... l

SAlE W· PADDY SA12 5A12

a 10 20 30 40 SO EO

soDa

4375 3750 3125 2500 1675 1250 525

a a

20 ⁴⁰ 50 ⁶⁰ lOa 12C

,--2 2

-~

2 2 2 -

a 10 20 30 40 so 50

por ....

^SH (~.G/HA)

SR'(21N·

pf,GOY

~==t::=4!:I.=f!:~~t~t.~'- T

o

lG 20 30 4C ~O 50

SRY21 W· PAOey

a

^{iO 20 30 40 50} ~a

5RY21

N·

PA[JCY

~ 5000

<. _4~~C;

:I: _J/w

"

:...J

~ 3750

c 3125

...J 2500

;::::

>- i575

1250 SC:5

a

(J 2C 40 SO ^{1=('~~ Lv",}

.""

i20

"JITRSG['; ':''':-JH .... )

Figure A.2 (contd)

5RYl

-23-

5RY1.

^'N.

DADDY 5RY1. W· PACOY

5000 4315 3750 31.25 2500 1615 1250 525 a

a 20 40 60 80 leo 120

NITRGG[N (K.G/HAl

5RY3i W· PADDY

a

10 20 30 40 50 50

PHOSPHGROUS (KG/HAl

5RY31

'N.

P.-'DDY

a 10 20 30 40 50 60

PQTASH (KG/HAl

5RY31 W· PADDY

CI

.... d

>-

5000 4375 3750 3125 2SCO 1675 1250 625

a

a 20 4Q 50 so loa 120

NITROGEN (KG/HAl

a

10 2G 3C 40 50 50

PHOSPYGRGUS (KG/HAl

a 10 20 30 4G 50 SO

GAl w·

^PADCY

6Ai w·

^{PACCY 6f.l}

w·

^P,A,GDY

5000

~ t ^T

<.

~ 4375

'. T

LJ 3750

'" / r=

Q 3125

d

2500

...

>- 1675

1250 525

a a

20 40 EO 60 100 120

a

10 20 30 40 '50 50

a

10 20 30 40 SO 50

NITROGEN (~G/HA) PHClSPHOROUS tKG/HM POTASH (KG/HAl

7LCAl W· P.j· 7LCAi W· P,\OCY 7LCAl W· PADDY

<. 50eo

~ 4375

"-

<..::

~ 3750

c 3125

d

2500

...

>- 1675 ^{c:: c::}

1250 625

a a

^{20 40} ~o

se

100 120

a

10 20 30 40 50 60

a

10 20 30 40 SO 60

~ITRCGEN l~G/HA) PHCSPHGRC~S iKG/HAl PCTASH (KG/HAl

78-RY W· p/\[JCY

78-RY

W· PADDY 76-hY W· PAOGY

5000

~375

3750 31C'5 250'3 lS75 lESO

~25

a

_{C Ie 2'J :JG ':0 :0 ~G}

t

₀ ,.

."

...^I _2'3^I ₃₀^I _de^I

so

^I 50^I

Figure A.2 (contd)

85M1 w.

C::,~OOy

-25-

8SMl w·

^p.~\OOy

8SMl

W·

PACey

5000 4315 31::0 3.i.25 c501J 1675 1250 625

o o

20 ~o 60 6C

lca

¹²⁰

r-.jITROGEN (I<.G/HAJ

o

^{10 20 30 40 50 60}

PYG5F~GROUS (KG/HAl

a

^{10 20 30 40 50 60}

POTASH (KG/H!ll

Figure A.3 Yield Response of Autumn Paddy

a

10 20 30 4C SO 50

°GTASH (KG/HAl

A· PADDY 5RY1*

PHOSPHOROUS (KG/HAl

5RY1-

o

10 20 30 40 50 60

5RY1* A· PADDY

-

^100CO

r

<I

"-

i.:) 6750

V

~

0..J

7500 w~

>-

6250 '5000 3750 2500 1250

a

Q 2-:J 40 50 80 lCG 120

~ITRaGE~ (KG/HM

-27- Figure A.3

.(contd)

a

10 20 30 40 50 60

A· PADDY 5ALRi'"

o

1.0 20 30 40 50 60

t

f

A· PADDY

PHSSPH8RC~S l~G/HA)

6~.LRY!t E~.LR·(^It A, p~,DOY

< seec

J: 4:i15

....

~ 3150

..::

c 3125

-J 2500

-

..;^>- _1.6i5

1.250 ^{c= c= r::}

625

0 ^{I I} I I I

a 20 40 50 60 1.00 12~

NITROGEN ^(KG/HAl

6-708"

A· PADDY

6-708

¹¹ A· PACIDY

5-706·

A· PADDY ,...

<- :I:....

CJ

~

C....J WJ

....

>-

5000 4375 3750 31.25 250G 1515 1.250

o

a 20 40 60 50 l.OC 1.2G

a

10 20 30 40 SO 60

o

10 20 30 40 50 ~c

7LC:\14 ",' PAGOY 7LCA14 ",. PADDY 7LC ..U4 sooa

4315 3150 31.25 25CO 1.575 '125

o

o 2G 40 SO SO 1.00 12a

t

_{0 10}^I ₂₀^I ₃₀^I ₄₀^I _SO^I ₅₀^I

_o

_{10 20 30 40 50 SO}

Yield Responses of Wheat Figure

A.4

2GB

• ·WHE.I\

~

~

::0-:']

T

<I... .:375

w 1750

..:

c 3.i.25

..J ~C:"'II'\

... l:_"""""

...

>- 16/5

!.2~C

525

a c

2G 40 50 SO lCC 120

"lITRSGEN iKG/H,.'l

2GB ··WHEAT

+

^I

T

o

10 20 30 40 50 60

2GB

^{... wHEAT}

T

or_I

t

I

} T

⁾

^,

^{f i !}

^{. -:t}

I

^{I I I I I I}

a 10 2G ³⁰

...

^'ro SO ^~tJ·.J...

i:'CT."SH (KG/HAl

2MB ^ltltWHEA T 2MB uWHEAT

2MB

"WHE.-\T

.... ^5GIJ'J

f f

~ .:375

'"

l..JL 3750

T f

0 3ic~

T

..J 2500

...

~

... _I

>- 1615

+

₁ 1 to 1 ^{1 };-}

1250625

~ T ^"F- T r

^{( ( -<}

a

^{I I I I I I}

,

I I I I I I

,

0 2G 40 50 60 leo 12G 0 10 20 30 40 50 SO 0 10 2'J 30 40 SO SO

I\iITRGGE~ (KG/HAl PHCr';Pl.fCRCL:S lKG/H.".) PG~I"S~ (KG/H ..,)

o 2G 4a 6C

=CG'J

<I ..375 ...

... c: .,

L j/ -\.,

-.-c:

0 ^J.LC_

... c50~

>- iSiS

.:.250

~25

0

2[51 ",.WhEAT

T

T t

L-+I--+-I

_{5C iCC 12C}^-+-1---/1

2[51 ·"WHEAT

t

T^I

'T

~

i

t

or _

r

_{C 10}~^I ₂₀^I ₃₀^I ₄₀^I _5C^I _SO^I

2[51

^uWf1E/H

i

"1'"

I TI

~

4-

T

T

I 3

T

! ^I I I

I

^I

a

^{10 20} JC ... 0 ^'Oro_u ~G

Figure A.4 (contd)

JA11 .."WHE,". T

-29-

3A11 .... WHEAT

<:

r....

l.::l

:.:::

.;315 3750 3i25 2500 lCi/5 1250 625

o

5000 4375 3750 3125 2500

l6/5 12S0 525

o

o

^{20 40 60 SO iCC l2G}

~rTRGGEN (KG/HAl

3A21 ^ItItWHEA T

o 20 40 EO so180 12C

~rTRCGEN (KG/HAl

TI

~

I

t:=::

T

^{I I I I I I}

Q 10 20 30 40 ~o 60

3A21 .. "WHEAT

T_I

+

I

t:=:=

I

^{I I I I I I}

C 10 20 30 40 50 60

c:'~SSF'HCRGUS iKG/HA)

o 10 20 30 40 sa 6J

DC::\SH (KG/H,")

3A21 "'WHE:\T

I I

T ~

^I

~8-

T

3 3

T

I f I I I I I

C 10 2G ]C 40 ~G ~C

3GB ·-WhEAT 3GB u'Nf-fEAT

3G8

.. • W:-iE:\ ,.

5C'J') T

T

^T

<: I I

I ^.-~c;

.... ^".J/_

T

^I

⁺

l.J:.::: 3750 T

1.

~

~

^I

Q 31.25

±

-l 2500 ^{i 1 1 i} 1 :i:

~ "t t'

....

_i

>-

t ^.

^I

i5/5 ^...--- _j

...

^I

12se ^.l.

r

t

^{I T}

c:-c; 1

.•c~

0 I I I I

T ,

I

,

I I I I .1 I I I I I

0 20 ..:c -"^-;:'"J 501,::>J 12:' 'J LG 2S ^3(; ~c ~c ^1=:".\J ,..^{J .L. ;)}

.

.., _2-'"^{. J} 1G ...^." '"-"".'-' SG

~ITRCCE~ (~G.·'iA) c:'HCSF''1C~CGS ,~G/HA) ;:C⁷i\SCj IKGI'1.~

;

Figure A.4 (contd)

3M63 tf ..WHL" T 3!vlB3 * •WHEA T ^3MB3 ,. .. ¥.'i-1E:\ -:-

Cl ...i

...,...

>-

~315

3150 2500 1375 1250 525

o ~ _{I , ,}

_{I , , ,}

IJ 20 ";0 50 50 loa 120

~!TRGG[N lKG/HAl

T,

T

~

I I

L::: ~

~f---'II---Ir----j

C 10 2a 30 40 50 SO

T

I

T

~_---il,--...,1r----11

~'I/ _a

_{10 20 30 40 ~c 50}

PGTASli (KG/HAl

3M 54

^uWHEAT

3M54

.... WHEAT

3M54

"'WHEAT

~oa~

f

< T

4375 I

J:

^" T

o.:l 3750

:.:::

t

3'-C:

=:^...J ₂₅₀₀^.I.e...;

T

... t

....

>- 1675

1250

~

t:: ^t:::

625

C I I I I I I

.J 20 4G 5a SG 100 12'::; ^I"v iO 2C 30 40 SO 50 ^C 10

eo

30 ciQ

""

^~v

.--

~~\J

~:T~:JGE~ (KG/HAl '-'!-tGS?!-tGRGCS lKG/H." 1 c:::; ""I~SI1 (KG/HI'.;

...,

....

>-

~375

3750J 3125 1575

lese

a

^{I I i i ' i}

G 20 40 60 ~O lOG 120

4All "*WHEA T

~

.

.L

t::= _T

T

I I I I I I I

C 10 20 30 40 SO SO

TI

T

T

+

I _{1 1 1} .... t

..

c

-

2 ^c.

1---2

^c.

-rI

I I I i I I

J lG

cS

^{30 ~:J \.;,'".U} "":'..J^-.,