SITE-SPECIFIC NUTRIENT MANAGEMENT (SSNM)
Guangdong, China
Team Leader
Dr. Xuhua Zhong
Crop Physiologist
The Rice Research Institute
Guangdong Academy of Agricultural Sciences
Guangzhou 510640
Email: xzhong8@163.com
Partner Institution
Guangdong Academy of Agricultural Sciences
Site Characteristics
Guangdong Province is located in the southeast of China’s mainland where it occupies an area of 178,000 km2. Two rice-growing seasons are practiced in Guangdong:
Rice is established by either transplanting or seedling throwing. The climate is subtropical with warm temperatures and adequate rainfall (annual mean precipitation = 1366 mm).
Rice occupies 2.14 million hectares (ha) of planting area in Guangdong Province, mainly planted in the plains near the Zhujiang, Hanjiang, Jianjiang, and Nanduhe Rivers, and in basins in hilly regions. Huiyang, Jiangmen, Guangzhou, and Zhaoqing are the main districts for rice cropping, with planting area of more than 220,000 ha.
Development and Evaluation of SSNM
In 2003-05, on-farm trials were conducted to evaluate N management options through use of a chlorophyll meter (SPAD), and determine nutrient-limited yields through the nutrient omission plot technique. N management options were first evaluated using SPAD, but starting 2004, the four-panel IRRI leaf color chart (LCC) was included in the development of improved N management practices, gradually replacing the more expensive SPAD meter.
Research Results
Attainable yields and nutrient deficits (2004-05)
The nutrient omission plot technique was used to determine attainable yield with full fertilization and nutrient-limited yields (Table 1). 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 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.
Table 1. Rice yields obtained with the nutrient omission plot technique in farmers’ fields in Guangdong, 2004-05.
|
Parameter |
Early ricea |
|
Late riceb |
||
|
|
Mean |
SD |
|
Mean |
SD |
|
Attainable yield target; yield with NPK (t ha−1) |
6.4 |
0.2 |
|
7.6 |
0.5 |
|
N-limited yield; yield without fertilizer N (t ha−1) |
5.0 |
0.4 |
|
4.7 |
0.6 |
|
Yield response to N (t ha−1) |
1.4 |
- |
|
2.8 |
0.9 |
|
- |
- |
|
7.2 |
0.6 |
|
|
Yield response to K (t ha−1) |
- |
- |
|
0.4 |
0.9 |
SD = standard deviation.
a Estimated from field experiments conducted at Guangzhou in 2004 and 2005.
b From the experiment conducted in 2004 late season in 10 farmers’ fields.
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. Recommendations for early and late rice crops are available at the links below.
SSNM recommendation for transplanted early rice
Version 2.0 [PDF 163kb]
SSNM recommendation for transplanted late rice (inbred and hybrid)
Version 2.0 [PDF 122kb]
Guangdong, China SSNM version 2.0 (www.irri.org/irrc/ssnm)
Site Specific Nutrient Management