SITE-SPECIFIC NUTRIENT MANAGEMENT (SSNM)
Team Leader
Dr. Brahma Mishra
Professor of Soil Science
College of Agriculture
G.B. Pant Univ. of Agric. and Technology
Pantnagar, 263145, U.P., India
E-mail: b_mishra_2001@yahoo.com
Partner Institution
G.B. Pant Univ. of Agric. and Technology
Site Characteristics
Uttar Pradesh is a large rice-growing province in northern India. Much of the arable land in the province is part of the Indo-Gangetic Plains, where rice-wheat rotation is the major cropping system. Uttaranchal is a small province formed in 2000 from part of Uttar Pradesh.
The lowland area by Pantnagar in Uttaranchal is representative of the rice-wheat cropping system extending across Uttar Pradesh
§ Rice is grown in the rainy (kharif) season from mid June until the end of October.
§ Wheat is grown in the winter (rabi) season from November until the end of March.
The hot and dry summer season from April to June is a fallow period.
The climate in Uttaranchal is subtropical. The average annual rainfall at Pantnagar was 1350 mm in 1989−1999. The soils near Pantnagar mostly developed on the calcareous outwash of alluvial deposits and are classified as deep to very deep mollisols. Soil textural classes are clay, sandy clay, and sandy clay loam.
Development and Evaluation of SSNM
On-farm research for the development of SSNM in Pantnagar, Uttaranchal began in 1997. Since 2001, on-farm research focused on the refinement and evaluation of refined SSNM strategies in pilot villages around Pantnagar. Recent SSNM activities in Uttaranchal included 1) participatory on-farm research and evaluation of N management options, 2) examination of responses to fertilizer K application, and 3) dissemination of SSNM strategies in pilot villages.
Research Results
Attainable yields and nutrient deficits
The nutrient omission plot technique was used to determine attainable yield with full fertilization and nutrient-limited yields. Table 1 shows the results in the kharif season in 2003-04. Rice grain yield in plots fully fertilized with N, P, and K provided an estimate of the attainable yield target. The yield of rice not fertilized with N but fertilized with other nutrients was used to determine N-limited yield. Similarly, the yield of rice not fertilized with P but receiving other nutrients indicated P-limited yield; and the yield of rice not fertilized with K but receiving other nutrients indicated K-limited yield. The difference between the yield target and a nutrient-limited yield indicated the crop response to the nutrient. This response averaged 0.3 t ha−1 for P and 0.8 t ha−1 for K (Table 1).
Table 1. Rice yields obtained with the nutrient omission plot technique in farmers’ fields in the kharif season in Pantnagar, Uttaranchal, 2003-04. Values shown are means and standard deviation (SD) of 12 farmers’ fields.
|
Parameter |
Kharif rice |
|
|
|
Mean |
SD |
|
Attainable yield target; yield with NPK (t ha−1) |
6.8 |
0.2 |
|
N-limited yield; yield without fertilizer N (t ha−1) |
3.2 |
0.3 |
|
P-limited yield; yield without fertilizer P (t ha−1) |
6.5 |
0.2 |
|
K-limited yield; yield without fertilizer K (t ha−1) |
6.1 |
0.2 |
|
Yield response to N (t ha−1) |
3.6 |
0.2 |
|
Yield response to P (t ha−1) |
0.3 |
0.1 |
|
Yield response to K (t ha−1) |
0.8 |
0.2 |
SSNM-based nutrient requirements
The SSNM approach was used to estimate fertilizer N, P2O5, and K2O requirements based on the results in Table 1. Total fertilizer N required for rice (Table 2) was estimated from the measured response to N (Table 1) and an assumed target agronomic efficiency of N (kg yield increase kg fertilizer N−1) of 25. See N management for more details.
Total fertilizer P2O5 and K2O were estimated from attainable yield target, P-limited yield, and K-limited yield (Table 1) using the nutrient decision support system (NuDSS) software. Straw input was estimated as 2 t ha−1.
Table 2. Fertilizer N, P2O5, and K2O requirements for kharif rice estimated from results with the nutrient omission plot technique in Pantnagar, Uttaranchal, India, 2003-04. Values shown are means and standard deviation (SD) of 12 farmers’ fields.
|
Parameter |
Kharif rice |
|
|
|
Mean |
SD |
|
Total fertilizer N required (kg ha−1) |
144 |
8 |
|
Total fertilizer P2O5 required (kg ha−1) |
31 |
1 |
|
Total fertilizer K2O required (kg ha−1) |
64 |
3 |
Locally Adapted Recommendation
Results from the nutrient omission plot trials and evaluation of N management options were used to formulate locally adapted recommendations for managing N, P, and K. A recommendation for transplanted rice is available at the link below.
SSNM recommendation for transplanted rice
Version 1 [PDF 125kb]
Uttaranchal, India SSNM version 1.0 (www.irri.org/irrc/ssnm)
Site Specific Nutrient Management
