SITE-SPECIFIC NUTRIENT MANAGEMENT (SSNM)
Cauvery Delta Zone, Tamil Nadu, India
Previous Team Leader
Dr. S. Ramanathan
Director of Research
Tamil Nadu Agricultural University
Coimbatore, Tamil Nadu
Current Team Leader
Dr. B. Chandrasekaran
Director of Research
Tamil Nadu Rice Research Institute
Aduthurai, Tamil Nadu
Dr. T. Jayaraj
Professor and Head
Soil and Water Management Research Institute
Kattuthottan, Thanjavur
Tamil Nadu
Email:
tnj_swmri@sancharnet.in
Dr. Ramasamy Rajendran
Professor of Agronomy
Tamil Nadu Rice Research Institute
Aduthurai, Tamil Nadu
Email:
rajendrankmu@yahoo.co.in
Partner Institutions
Tamil Nadu Agricultural University
Tamil Nadu Rice Research Institute
Soil and Water Management Research Institute
Tamil Nadu is one of the most important states for rice production in India because of its favorable soil and climatic conditions. The state ranks fifth in rice production in India, with yields among the highest in the country. Within Tamil Nadu, the Cauvery Delta Zone is a major area for production of irrigated rice.
The Cauvery Delta Zone has a humid tropical monsoon climate with an average annual rainfall of about 1000 mm. Most of the rain falls during the monsoon season from September to December, which is also associated with lower solar radiation and temperature of 20–30°C.
Farmers grow one or two rice crops per year, commonly established by transplanting. The double rice cropping system has the following two seasons:
The single rice cropping system is typically from August to January. This is a wet season referred to as samba. Rice cultivars are typically long duration: about 155 to 165 days from seed to harvest. Farmers also grow non-rice crops such as pulses, cotton, and sesame after wet-season rice (thaladi or samba).
Rice soils in the Cauvery Delta Zone are dominated by alluvial soils low in soil organic C and total N, with a neutral to slightly alkaline pH. Soils in the Old Delta are heavier in texture (clay loam to clay), whereas soils in the New Delta are lighter in texture (sandy loam to clay loam) with good drainage.
Development and Evaluation of SSNM
Research on SSNM started in 1997 in farmers’ fields at a site near Aduthurai in the Old Delta, and a site near Thanjavur in the New Delta (Fig. 1). From 2001 to 2005, the research expanded to include on-farm trials across more villages in both the Old and New Delta.
Fig. 1. The sites for the development and evaluation of SSNM in the Cauvery Delta Zone, Tamil Nadu, India.
Attainable yield 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 2002 to 2004. 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. Crop response to P averaged <0.5 t ha−1 in both the Old and New Delta for both kuruvai and thaladi seasons. Crop response to K averaged 0.5 t ha−1 for both kuruvai and thaladi in the Old Delta and >0.5 t ha−1 for both seasons in the New Delta.
Table 1. Attainable yield and nutrient deficits in the Old and New Delta in Tamil Nadu, 2002 to 2004. Values shown are means and standard deviation (SD) of 25–40 farms per location and season.
|
Location and parameter |
Kuruvai (dry season) |
|
Thaladi (wet season) |
||
|
|
Mean |
SD |
|
Mean |
SD |
|
Old Delta (Aduthurai District) |
|
|
|
|
|
|
Attainable yield target; yield with NPK (t ha−1) |
6.2 |
0.8 |
|
6.2 |
0.5 |
|
N-limited yield; yield without N fertilizer (t ha−1) |
3.9 |
0.6 |
|
3.8 |
0.6 |
|
P-limited yield; yield without P fertilizer (t ha−1) |
5.9 |
0.8 |
|
5.8 |
0.5 |
|
K-limited yield; yield without K fertilizer (t ha−1) |
5.7 |
0.8 |
|
5.7 |
0.5 |
|
Yield response to N (t ha−1) |
2.3 |
0.6 |
|
2.4 |
0.8 |
|
Yield response to P (t ha−1) |
0.3 |
0.3 |
|
0.4 |
0.3 |
|
Yield response to K (t ha−1) |
0.5 |
0.3 |
|
0.5 |
0.3 |
|
New Delta (Thanjavur District) |
|
|
|
|
|
|
Attainable yield target; yield with NPK (t ha−1) |
6.5 |
0.8 |
|
6.2 |
0.5 |
|
N-limited yield; yield without N fertilizer (t ha−1) |
4.1 |
1.0 |
|
3.9 |
0.6 |
|
P-limited yield; yield without P fertilizer (t ha−1) |
6.0 |
0.8 |
|
5.9 |
0.5 |
|
K-limited yield; yield without K fertilizer (t ha−1) |
5.7 |
0.7 |
|
5.6 |
0.3 |
|
Yield response to N (t ha−1) |
2.4 |
0.9 |
|
2.3 |
0.8 |
|
Yield response to P (t ha−1) |
0.5 |
0.3 |
|
0.3 |
0.2 |
|
Yield response to K (t ha−1) |
0.8 |
0.3 |
|
0.6 |
0.3 |
SSNM-based nutrient requirements
The SSNM approach was used to estimate fertilizer N and P2O5 requirements from Table 1. Total fertilizer N required for rice (Table 2) was estimated from the measured response to N (Table 1) and assumed target agronomic efficiency of N (kg yield increase kg fertilizer N−1) of 20 for both the kuruvai and thaladi seasons.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 1 t ha−1 for the kuruvai season and 2 t ha−1 for the thaladi season.
Table 2. Fertilizer N, P2O5, and K2O requirements for rice estimated from results with the nutrient omission plot technique in the Old and New Delta in Tamil Nadu, India, 2002 to 2004. Values shown are means and standard deviation (SD) of 25–40 farms per location and season.
|
Location and parameter |
Kuruvai (dry season) |
|
Thaladi (wet season) |
||
|
|
Mean |
SD |
|
Mean |
SD |
|
Old Delta (Aduthurai District) |
|
|
|
|
|
|
Total fertilizer N required (kg ha−1) |
115 |
30 |
|
119 |
39 |
|
Total fertilizer P2O5 required (kg ha−1) |
29 |
4 |
|
27 |
3 |
|
Total K2O required (kg ha−1) |
64 |
14 |
|
50 |
11 |
|
New Delta (Thanjavur District) |
|
|
|
|
|
|
Total fertilizer N required (kg ha−1) |
120 |
44 |
|
115 |
38 |
|
Total fertilizer P2O5 required (kg ha−1) |
31 |
5 |
|
28 |
3 |
|
Total K2O required (kg ha−1) |
72 |
15 |
|
53 |
13 |
Locally Adapted Recommendation for Rice in Tamil Nadu
Results from the nutrient omission plot technique, on-farm evaluation of SSNM, and interviews with farmers were used to formulate locally adapted recommendations for managing N, P, and K.
Locally adapted SSNM recommendations for transplanted rice with growth duration of 110 to 115 days for the kuruvai season and 130 to 135 days for the thaladi season are available at the links below.
SSNM recommendation for transplanted rice in kuruvai (dry) season
SSNM recommendation for transplanted rice in thaladi (wet) season
Cauvery Delta Zone, Tamil Nadu, India SSNM version 1.0 (www.irri.org/irrc/ssnm)
Site Specific Nutrient Management
