Americas and Oceania Group - International Plant Nutrition Institute

with the actual village map accessed from Google Earth and 8 on-farm trials, one in each management zone,
were set up in monsoon rice. The following treatments were used to assess the suitability of the fertilization
strategy based on management zone approach as well as to estimate nutrient response variability between
the management zones: T1: Farmers’ practice; T2: Soil-test based targeted yield approach; T3: Management
zone approach using GIS map; T4: Ample NPK; T5: Ample PK; T6: Ample NK; and T7: Ample NP. Rice
yield was highest (4.2 t/ha) under targeted yield approach treatment in all the management zones with a range
of 4.0 to 4.4 t/ha. The management zone-based approach and ample NPK treatments resulted in equivalent
average yield levels of 3.9 and 4.0 t/ha respectively. Average yield loss in N, P, and K omission plots were 2.1
(range 1.9 to 2.3), 1.8 (range 1.6 to 1.9) and 1.6 (range 1.3 to 1.7) t/ha, respectively. Similar experiments in
wheat, with an additional treatment of Nutrient Expert decision support tool based nutrient recommendation,
is in progress. India-001
Addressing Multi-Nutrient Deficiencies through Site-Specific Nutrient Management
Project Leader: B.S. Dwivedi, Indian Agricultural Research Institute Division of Soil Science and Agricultural
Chemistry, New Delhi, Delhi. E-mail: bsdwivedi@rediffmail.com
Project Cooperators: Dhyan Singh (Principal Scientist) Anand Swarup (Division of Soil Science and Agricultural
Chemistry), K.S. Yadav, and Krishi Vigyan Kendra (IARI), Shikohpur
Incidence and expansion of multi-nutrient deficiencies in Indian soils owing to inadequate and unbalanced
nutrient input is considered as one of the major reasons for decline in factor productivity of crops. The
problem is more acute in intensively cropped areas, where annual nutrient removal by the crops often far
exceeds replenishments. Diagnostic surveys indicate that in several high productivity areas of irrigated
ecosystems, farmers often resort to excessive use of fertilizer N to maintain the yields at levels attained
previously with relatively lower fertilizer rates. Such indiscriminate use of N fertilizers not only aggravates
soil fertility depletion with respect to nutrients other than N, but also proves ultimately harmful in terms of
low nutrient use efficiency, poor quality of produce, enhanced susceptibility of crops to biotic and abiotic
stresses, and a potential threat of groundwater.
In the present era of multi-nutrient deficiencies, site-specific nutrient management (SSNM) is one of
the good options to arrest the decline in soil fertility. A thorough understanding of the nature and extent of
nutrient deficiencies in the soils of different agro-ecologies is a pre-requisite for developing SSNM strategies.
In order to bridge the existing knowledge gaps on these aspects, the present research project was initiated for
assessment of multi-nutrient deficiencies in a village or a cluster of villages in the agriculturally important
agro-ecological subregions (AESRs). Widespread multi-nutrient deficiencies involving 2 to 5 nutrients
were observed in different AESRs. SSNM strategies based on such information produced better yield and
economics than state recommendation and farmers’ fertilizer practice in several cropping systems. Attempts
were also made to establish relationships between spread of nutrient deficiencies and nutrient use by the
farmers in the sampled villages of different AESRs. Results indicated significant relationship between P
and K deficiencies with the use of these nutrients in some AESRs, while the relationships were generally
inconsistent for other nutrients. Multi-nutrient deficiency maps of the sampled areas from different AESRs are
being developed utilizing soil test data and GPS coordinates of sampling points. Information on assessment
of multi-nutrient deficiencies in different AESRs and from SSNM experiments are being compiled into a
research bulletin. India-004
Fertility Mapping and Balanced Fertilization for Sustaining Higher Productivity of Pearl Millet-Wheat Cropping System
in Agra District
Project Leader: Vinay Singh, Raja Balwant Singh College, Agra University Department of Agricultural Chemistry &
Soil Science, Bichpuri Agra, Uttar Pradesh. E-mail: apsr_1999@yahoo.co.in
The project assessed a plant-based approach to develop SSNM strategies for pearl millet-wheat system.
Omission plot trials in farmers’ fields helped assess the wheat nutrient response in the study area. This
information was used in the Nutrient Expert (NE) for wheat, a nutrient application decision support tool
to develop field specific nutrient recommendation. The relative performance of NE generated fertilizer
recommendation was compared to a soil-test based recommendation (OPT) and the existing general fertilization
practice (SR) in 16 farmers’ field trials. The trials assessed five treatments: (i) OPT (180 kg N, 90 kg P 2 O 5 , 100
kg K 2 O and 40 kg S/ha); (ii) OPT-N; (iii) OPT-P; (iv) OPT-K; (v) State Recommendation (120 kg N, 60 kg
P 2 O 5 , 40 kg K 2 O/ha); and (vi) NE (140 kg N, 68 kg P 2 O 5 and 81 kg K 2 O/ha ) for a target yield of 6 t/ha. The
soil test-based recommendation produced the highest wheat grain yield (5,847 kg/ha) followed by nutrient
recommendation from NE (5,639 kg/ha). Average grain yield in farmers’ fields under State Recommendation
(SR) was 5,223 kg/ha. Omission of nutrients reduced wheat grain yield by 38.1 % (- N), 20.7 % (-P), and 23.1
% (-K). The optimum treatment (OPT) produced higher net returns (INR 57,673/ha) than SR (INR 50,917/
IPNI Interpretive Summaries 89