User manual | Low and Declining Crop Response to Fertilizers

35
LOW AND DECLINING CROP
RESPONSE TO FERTILIZERS
NATIONAL ACADEMY OF AGRICULTURAL SCIENCES, NEW DELHI
MAY 2006
Convener
:
Dr. Rajendra Prasad, Ex ICAR National Professor & Ex INSA Senior Scientist
Editors
:
:
Prof. B.N. Johri
Dr. J.S.P. Yadav
Co-ordinator (Publication) :
Prof. V. P. Gupta
:
Citation
NAAS. 2006. Low and Declining Crop Response to Fertilizers. Policy Paper No. 35,
National Academy of Agricultural Sciences, New Delhi. pp 8.
EXECUTIVE COUNCIL 2006
PRESIDENT
MEMBERS
Prof. M. S. Swaminathan (Chennai /Delhi)
IMMEDIATE PAST-PRESIDENT
Prof. V. L. Chopra (Delhi/Palampur)
Dr. S. S. Acharya (Jaipur)
Dr. T. K. Adhya (Cuttack)
Dr. Anwar Alam (Srinagar)
VICE-PRESIDENTS
Dr. C. R. Bhatia (Navi Mumbai)
Dr. Mangala Rai (Delhi)
Dr. (Mrs.) Satinder Bajaj (Noida)
Dr. B. V. David (Chennai)
SECRETARIES
Dr. P.V. Dehadrai (Delhi)
Dr. R. K. Singh (Delhi/Lucknow)
Dr. S.P. Ghosh (Kolkata/Delhi)
Dr. M.L. Madan (Karnal)
Dr. S. L. Intodia (Udaipur)
FOREIGN SECRETARY
Dr. S. M. Virmani (Hyderabad)
Dr. S. S. Kadam (Parbhani)
EDITORS
Dr. I. C. Mahapatra (Bhubaneswar)
Dr. B. N. Johri (Bhopal)
Dr. J.S.P. Yadav (Delhi)
Dr. B. N. Mathur (Amritsar)
Dr. P.S. Pathak (Jhansi)
TREASURER
Dr. M. L. Lodha (Delhi)
Dr. Rita Sharma, FA, ICAR Nominee (Delhi)
Published by M. Vijaya Kumar, Executive Secretary I/C on behalf of
National Academy of Agricultural Sciences,
NASC Complex, Dev Prakash Shastry Marg, Pusa Campus, New Delhi 110012
Tel: (011) 25846051-52, 25841253; Fax: (011) 25846054
Email: [email protected]; Web site: http://www.naas-india.org
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LOW AND DECLINING CROP RESPONSE
TO FERTILIZERS
PREAMBLE
With an annual compound population growth rate estimated at 1.97%, nearly 20 million new
mouths equivalent to the present population of Australia are added to India each year.
Providing two meals a day to its people will always remain one of the major concerns of the
Government. Foodgrain demand of India is estimated at about 300 million tonnes per annum by
2020, necessitating an increase of about 91 million tonnes (Mt) from the estimated 209 Mt
production for 2005-06. Since there is no likely prospect of any further increase in the area
under cultivation over the present 142 million hectares, much of the desired increase in
foodgrain production has to be attained by enhancing the productivity per unit area. The
productivity of rice has to be increased from the present 2077 kg/ha to 2895 kg/ha by 2020 with
an average increase of about 5% per annum. The productivity of wheat has to be increased from
the present 2713 kg/ha to 3918 kg/ha with an average increase of about 7.5% per annum, while
the productivity of pulses has to be increased from the present 637 kg/ha to 1282 kg/ha with an
average increase of about 5.3% per annum. On the contrary, the productivity of most foodgrain
crops except wheat has shown a negative growth rate of 0.72 to 1.84% per annum during the
period 2000-01 to 2002-03. This poses not only a matter of great concern but also a formidable
challenge.
The foodgrain production, following the green revolution in 1969-70, was 99.5 Mt and nearly
doubled by the end of the last century. The highest average annual increase of 6.1% in
foodgrain production was recorded during 1980's; from 110 Mt in 1979-80 to 171 Mt in 1989-90,
but the annual increase in foodgrain production during 1990s dropped to 1.5%. The fact that
the fertilizer was the key input in augmenting foodgrain production after the availability of the
seeds of high yielding crop varieties, is evident from the increase in fertilizer (N + P2O5 + K2O)
consumption from 1.98 Mt in 1969-70 to 18.07 Mt by 1999-00. Nevertheless, the average
annual increase in fertilizer consumption witnessed a declining trend in these three decades, as
reflected by 16.5% during 1970's, 12.04% during 1980's and only 5.6% during 1990's.
A simple regression analysis between the foodgrain production and fertilizer consumption
during 1960-61 to 1999-00 showed that the partial factor productivity of fertilizers has been
continuously declining. The data available from some centres under the Project Directorate of
Cropping Systems Research (PDCSR), Modipuram also indicate a reduction in crop response to
fertilizer application, specially when balanced fertilization is not practiced. This is supported
by the fact that the farmers in the rice-wheat cropping system belt (specially Punjab, Haryana
National Academy of Agricultural Sciences
1
and Western U.P.) are forced to apply more and more fertilizer to obtain the same crop yields as
in the preceding years. The data from the trials on the farmers' fields conducted by the PDCSR,
Modipuram during 1999-2003 showed that the average response of cereals to fertilizer was 8-9
kg grain/kg fertilizer. The efficiency of fertilizer nitrogen is only 30-40% in rice and 50-60% in
other cereals, while the efficiency of fertilizer phosphorus is 15-20% in most crops. The
efficiency of K is 60-80%, while that for S is 8-12%. As regards the micronutirents, the
efficiency of most of them is below 5%. Attention to this serious problem of low and declining
crop response to fertilizer was drawn by Professor M.S.Swaminathan, President, NAAS in his
th
Presidential address on 5 June 2005.
In view of the above disturbing agricultural scenario, a two-day Brain Storming Session on
“Low and Declining Response of Crops to Fertilizers” was organized by the National Academy
th
st
of Agricultural Sciences at New Delhi on 20 and 21 February 2006 with Dr. Rajendra Prasad, Ex
ICAR National Professor and Ex INSA Sr. Scientist as the Convener. It was attended by 41
experts including some of the Directors of leading National Agricultural Institutes and
Professors/Scientists/Officials of the State Agricultural Universities/ Ministry of
Agriculture/FAI etc.
The deliberations included four technical sessions with key and panelist presentations followed
by discussion. Dr. R.B. Singh, Member, NCF, GOI in his inaugural address emphasized the need for
soil health card, and increasing the farm profit by improving the crop response to fertilizers.
Dr. J.S.P. Yadav, former Chairman, ASRB in the wrap up/concluding session listed several causes
of declining/low crop response to fertilizers and summarized recommendations made thereof.
It was vividly brought out in the deliberations that the major factor responsible for the low and
declining crop response to the fertilizers was the continuous nutrient mining of the Indian soils
without adequate replenishment to the desired extent. It is estimated that about 28 Mt of
primary plant nutrients are removed annually by crops in India, while only 18 Mt or even less are
applied as fertilizer, leaving a net negative balance of about 10 Mt of primary plant nutrients
(NPK).
An analysis of the data pertaining to rice-wheat cropping system from 24 research stations in
the Indo-Gangetic plains revealed that the rice yields are declining more rapidly as compared to
wheat yields, and soil K depletion seemed to be a general cause, whereas P and Zn depletion
emerged as a cause at some centres. Similarly, a study at ND University of Agriculture and
Technology, Faizabad showed that the yield decline in both rice and wheat was the highest
when N alone was applied at 120 kg/ha. As the depletion of native soil P increased with time,
the response of both rice and wheat to applied P showed an increase after 10 years of cropping.
Also, as the native soil K decreased over time, the response to applied K started to increase after
5 years in both rice and wheat. In wheat, it continued to increase even after 20 years, while in
rice the increase in response to K stopped after 15 years. Such reports are several in number.
2
Policy Paper 35
Furthermore, the soils are also getting continuously depleted of secondary plant nutrient S and
micronutrients. The marked deficiencies of S and Zn are widespread in the country and
significant responses to application of these nutrients are well documented. The deficiencies of
B, Fe and Mn are also being reported from some parts of the country. Thus, inadequate and
imbalanced fertilization is a major causative factor for low and declining crop response to
fertilizers. The need for integrated nutrient management including the use of organic sources
such as farmyard manure, rural and urban compost, vermi-compost, green manures, inclusion of
legumes in the crop rotations, growing of dual purpose short duration legumes such as
mungbean in the summer months in the rice-wheat cropping system, and bio-fertilizers was
emphasized for meeting a part of the plant nutrient needs of crops.
The major factor, responsible for the low response of crops to fertilizer nitrogen, is its low useefficiency, especially in case of rice crop where it is only 30-40% of applied N due to various N
loss mechanisms, namely, surface run-off, ammonia volatilization, leaching and denitrification.
In 1995, the global estimate of nitrogen loss, from the applied fertilizer N in 1995 through
ammonia volatilization was 11.2 Mt (14.45 %), while that through NO and N2O through
denitrification was 1.5 Mt (1%). India's contribution to these losses could approximately be
10% of the total. Ammonia added to the atmosphere leads to the acid rain, while NO and N2O are
responsible for the depletion of ozone layer in the atmosphere. In addition, nitrates leach to the
groundwater and lead to the nitrate pollution of drinking water which is injurious to health. An
increase in the nitrate content due to heavy N fertilization has been reported in Punjab by the
researchers at the Punjab Agricultural University. There is, therefore, an urgent need to develop
more efficient nitrogen fertilizers.
Some slow-release N fertilizers developed in the foreign countries are used on a limited scale in
case of high value crops due to their high costs. Similarly, nitrification inhibitors have also been
developed in some foreign countries as well in India, but their high cost and application
problems with some, such as N-serve, are constraints to their use. Studies in India showed that
coating urea with neem cake/oil/neem bitterns could retard the nitrification for 2-3 weeks. A
technology for coating urea with neem oil emulsion at the factory scale is now available in India
and the Govt. of India has permitted National Fertilizers Limited (NFL), Shriram Fertilizers and
Chemicals and Indo-Gulf Fertilizers to manufacture and market the neem-coated urea on an
experimental basis. The results obtained with neem-coated urea on the farmers fields have
shown a 2 to 10 % higher grain yield of rice as compared to uncoated urea. Taking a mean value
of 5% increase in nitrogen use-efficiency, a saving of 5 lakh tonnes of nitrogen per annum at the
current level of consumption of 10 Mt of N is estimated, which is equivalent to the combined
annual production of fertilizer N at Panipat and Bhatinda plants of NFL or the annual production
of fertilizer N at Jagdishpur plant of Indo-Gulf. There is a heavy demand of neem-coated urea in
several states of India, and therefore, production of neem-coated urea needs to be enhanced.
National Academy of Agricultural Sciences
3
RECOMMENDATIONS
Major recommendations emanating from the Brainstorming Session are given here under four
heads, namely (A) causes for low and declining crop response to fertilizers, (B) agenda for
research, (C) rejuvenation of agricultural extension, and (D) policy decisions.
A.
4
Causes for Low and Declining Crop Response to Fertilizers
•
Nutrient Supply and Soil fertility
•
Continuous use of fertilizer N alone or with inadequate P and K application leading to
mining of native soil P and K
•
Continued practice of intensive cropping systems like 'rice-wheat' with high yielding
varieties even under recommended NPK use, impoverishing soils of secondary and
micro nutrients specially S, Zn, Mn, B and Fe
•
Use of high analysis fertilizers and inadequate addition of organic manures resulting
in widespread deficiencies of S and micronutrients
•
Fertilizer application mostly not based on soil-test values
•
Inappropriate time and method of fertilizer application
•
Excessive use of irrigation in rice-wheat cropping system, sugarcane and other
heavily fertilized crops leading to leaching of nitrogen and other plant nutrients
•
Inadequate availability of appropriate kind of fertilizers at the right time
•
Antagonistic reaction between some plant nutrients
•
Low status of soil organic carbon
•
Subsoil impedance to plant root system restricting nutrient uptake
•
Soil degradation due to high salinity/sodicity/acidity/waterlogging, affecting
nutrient availability
•
Lack of adequate and quality soil testing facilities and meager availability of fertilizer
recommendations under aberrant weather conditions
•
Environmental degradation, having negative impact on belowground biodiversity,
especially agriculturally important microorganisms
Policy Paper 35
v
v
v
B.
Seed
•
Non-availability of sufficient seeds of high yielding varieties of crops at affordable
price and at the appropriate time
•
Lack of more efficient nutrient using genotypes
Agronomic Practices
•
Delayed sowings / plantings
•
Low seed rates resulting in poor crop stands
•
Poor weed management
•
Inefficient tillage
•
Inefficient irrigation and rainwater management
•
Large scale monoculture
•
Lack of consideration of previous cropping in the same field
•
Lack of capturing water-nutrient synergic interaction
•
Inadequate plant protection
Weather Aberrations
•
High intensity rain leading to nutrient loss
•
Abnormal high/low temperature
Agenda for Research
•
Nutrient budgeting in different crops/cropping system for different agro-ecological
zones needs to be done.
•
Site-specific fertilizer application practices (SSFAP) based on soil-test
recommendations need to be developed for various crops and cropping systems in
different agro-ecological zones of the country.
•
For sustainable agriculture, integrated plant nutrient supply systems (IPNS),
involving FYM, compost, vermicompost, green manures, dual purpose legumes (e.g.
summer mung in rice-wheat cropping system) and biofertilizers, need to be
National Academy of Agricultural Sciences
5
developed for various crops and cropping systems in different agro-ecological zones
of the country.
C.
•
SSFAP and IPNS also need to be developed for different agro-forestry systems,
integrated farming, orchards and peri-urban-agricultural systems involving
vegetables and flowers.
•
Fertilizer - irrigation water interaction studies need to be intensified.
•
Considering the fact that about 40-50% of the applied fertilizer nitrogen is not only
lost from the soil-plant system, but also adds to the environmental pollution, more
efficient nitrogen fertilizers, involving materials such as neem oil or cake or
indigenously developed nitrification inhibitors need to be developed for field
adoption.
•
Customized fertilizers based on soil-test-crop response studies for different regions
of the country are to be developed.
•
Research is needed on the use of soluble fertilizers/fertilizer solutions specially in
horticulture, vegetable crops and floriculture for drip irrigation system.
•
Since fertilizer nitrogen is used in the largest amounts and its efficiency is low,
development of accurate and site-specific recommendations for nitrogen based on
soil-test, plant-tissue analysis, use of chlorophyll meter and other techniques, if any,
is urgently needed.
•
Appropriate fertilizer recommendations for different crops grown in the dryland areas
need to be developed vis-à-vis weather aberrations.
•
There is need for developing a data base at IASRI, New Delhi for all the field
experiments conducted on crop response to fertilizers in the country. IASRI should
develop a suitable proforma for reporting of such data, which the ICAR should
circulate to all agricultural universities and ICAR/State Institutions for compliance.
•
The optimum doses of N, P and K need not be computed from the response curves.
These need to be computed by fitting response surfaces and using soil fertility status.
Rejuvenating Agricultural Extension
•
6
It is generally presumed that the farmers know all about fertilizers. This is a myth that
needs to be broken. One of the major constraints is the farmers' lack of awareness
about the concept of balanced fertilization not only about major elements but also
involving secondary and micronutrients.
Policy Paper 35
D.
•
Extension machinery needs to be geared up and rejuvenated/ revived.
•
Demonstrations are needed to emphasize the need for balanced fertilization of
N,P,K,S Zn, B, Fe and other micronutrients and on Integrated Plant Nutrient Supply
System (IPNS).
•
Demonstrations on the role of fertilizers for increasing crop yields under dryland
agriculture conditions are also needed.
•
The farmers need to be educated about the role of micronutrient plant nutrients in
human and animal health. This will encourage the application of micronutrients in
crop production.
•
Demonstrations are also needed to emphasize on the time and method of fertilizer
application.
•
The fertilizer industry should play an active role in conducting demonstrations in
respect of the balanced fertilization, IPN, as well as on time and method of fertilizer
application.
Policy Decisions
A long-term pragmatic policy for all fertilizer nutrients including secondary and
micronutrients is essential to achieve balanced nutrition to overcome soil fertility and
health degradation, and improve crop productivity on a sustainable basis. This includes:
•
Adequate number of well equipped soil-testing laboratories manned by well
trained personnel to take care of secondary and micronutrient analysis
•
Soil health cards for all the categories of the farmers throughout the country for
the purpose of periodical monitoring of soil fertility status and as one of the
sources for obtaining agricultural credit
•
Quality control for fertilizers including micronutrient fertilizers
•
Standardization of organic manures
•
Providing price incentives to the fertilizer manufacturers opting for the
manufacture of value-added fertilizers such as neem-coated urea and balanced
customized fertilizers
•
Strengthening collaboration between the fertilizer industry and National
Institutes engaged in developing soil test-based and site-specific nutrient
recommendations to develop soil and crop specific quality fertilizers
National Academy of Agricultural Sciences
7
•
Provision of a transparent regulatory framework for ensuring supply of tailormade crop and soil-specific quality fertilizers to the farmers and corresponding
provisions in the Fertilizer (Control) Order, GOI
•
More proactive State Fertilizer Review Committees having wider representation
of the scientists and the industry and empowered with quality control for
blended and value added fertilizers
•
Ensuring credit to the farmers at low interest rates for the purchase of fertilizer,
seed, pesticides, and agricultural equipment
•
Providing subsidies to promote cultivation of legume crops for green manuring/
grain to build-up soil fertility and to meet the shortage of pulse requirements in
the Country
•
Establishment of a National Network on Integrated Fertilizer Development for
Sustainable Agriculture by the ICAR/Ministry of Agriculture
•
Establishment of Co-ordination Cell for co-ordinating the activities of different
ministries of Govt. of India related to efficient use of fertilizers such as Ministry
of Agriculture, Ministry of Fertilizers & Chemicals, Ministry of Irrigation, I.C.A.R.
and National Commission for Farmers.
CONCLUSION
Fertilizer has been and will continue to be the key input for achieving the estimated foodgrain
production goals of the country. Since increase in foodgrain production is possible only through
the increased productivity per unit land, an all out effort is needed to increase the crop response
to fertilizers. Some of the suggested measures are balanced and adequate N,P,K,S, Zn, B and Fe
(and any other deficient nutrient) fertilization, Integrated Plant Nutrient Supply System (IPNS),
development of quality soil-test facilities at district/block level, timely availability of desired
fertilizer materials, availability of good quality seed of the recommended crop varieties,
implementation of recommended agronomic practices and availability of low interest credit to
the farmers. Considering the fact that about 40-50% of the applied fertilizer nitrogen is lost by
ammonia volatilization, leaching, run-off and denitrification, development of more efficient
nitrogen fertilizers such as neem-coated urea needs to be encouraged by providing price
incentive to the fertilizer manufacturers. Customized soil and crop specific fertilizer materials
need to be developed for major cropping and farming systems in different agro-eco regions.
Creation of a National Network on Integrated Fertilizer Development for Sustainable
Agriculture is urgently needed.
8
Policy Paper 35
PARTICIPANTS IN THE BRAINSTORMING SESSION ON
LOW AND DECLINING CROP RESPONSE TO FERTILIZERS
1.
Y.P. Abrol, New Delhi
21. Rajendra Prasad, New Delhi
2.
Masood Ali, Kanpur
22. B.K. Saha, New Delhi
3.
M.S. Aulakh, Ludhiana
23. A.R. Sharma, New Delhi
4.
P.K. Batra, New Dehli
24. S. D. Sharma, New Delhi
5.
P. Bhattacharya, New Dehli
25. S.K. Sharma, Meerut
6.
D.R. Biswas, New Delhi
7.
D. Blaise, Nagpur
8.
G. Chakraborty, New Delhi
9.
C. Devakumar, New Delhi
10. Gautam Goswami, New Delhi
11. Umesh C. Gupta, Canada
12. V.K. Gupta, New Delhi
13. V.P. Gupta, New Delhi
14. Dinesh Kumar, New Delhi
26. S.N. Sharma, New Delhi
27. Y.S. Shivay, New Delhi
28. Geeta Singh, New Delhi
29. R.B. Singh, New Delhi
30. R.K. Singh, New Delhi
31. R.P. Singh, New Delhi
32. S.P. Singh, Lucknow
33. A. Subba Rao, Bhopal
34. I.K. Suri, New Delhi
35. H.L.S. Tandon, New Delhi
15. Virendra Kumar, Ghaziabad
36. R.K. Tewatia, New Delhi
16. O.P. Meelu, Ludhiana
37. K. N. Tiwari, Gurgaon
17. G. Narayanasamy, New Delhi
38. N. Tripathi, Faridabad
18. B.S. Parmar, New Delhi
39. Pamidi Venkateswarlu, Hyderabad
19. Rajender Parsad, New Delhi
40. J.S.P. Yadav, New Delhi
20. Mangal Prasad, New Delhi
41. R.L. Yadav, Lucknow
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