Nutrient Management Strategies for Guangxi

Initiated in 2001, the purpose of this study is to track soil variability between and within villages and among village fields. These data, combined with other information from field trials and fertilizer use surveys, will be used to improve fertilizer use for high yield, high benefit crop production.

Soil testing was conducted during 2001 and soil nutrient variability maps were developed in 2002 using geographic information system software. Field trials were established to monitor the effect of different fertilizer treatments on crop yields and residual soil fertility. In the vegetable-corn-late soybean cropping system, application of nitrogen (N), phosphorus (P), and potassium (K) at 173-63-225 kg N-P₂O₅-K₂O/ha for turnip increased yield by 2,980 kg/ha (18%) compared to NP application alone. Compared to common farmer practice of applying 150-90-135 kg/ha for corn and late soybean, application of 225-90-203 kg/ha plus 30 kg/ha each of sulfur (S) and magnesium (MgO) increased corn yield by 265 kg/ha (4%) and late soybean yield by 98 kg/ha (6%). In the early rice-late rice system, balanced fertilizer application with 203-75-150 kg/ha plus 30-30 kg S-MgO/ha improved rice yield by 577 kg/ha (10%) compared with farmer practice of applying 135-75-75 kg/ha.

Guangxi Province currently uses the highest P and K fertilizer rates in southwest China. This research indicates additional need for P and K fertilizer. The technology of balanced fertilization can be extended to 1.2 million hectares (ha) of rice, 250,000 ha of soybean, and 170,000 ha of corn in Guangxi Province. Guangxi-NMS 02