Nutrient Management Strategies for Guangxi

Laibin County and Fushui County are long-term monitored village sites. Nutrient use and soil fertility data will be evaluated, in combination with information from field trials to developing site-specific soil fertility management zones. Soil testing was used to develop soil nutrient variability maps in 2002 and nutrient limitations are being verified by fixed-site field trials. This information will be used to develop reliable recommendations capable of sustaining crop yield and quality.

In sugarcane, the main nutrient deficiencies were potassium (K), phosphorus (P), sulfur (S), zinc (Zn), and boron (B). Balanced fertilization (BF) with 520-570-620 kg N-P₂O₅-K₂O/ha plus 60 kg S/ha, 11 kg Zn/ha, and 5 kg B/ha increased yield by 56.7 t/ha (47%) compared to the treatment without K. Cane yield decreased by 37% without P, by 21% without S, 17% without Zn, and 15% without B.

In citrus orchards, N, P, K, and magnesium (Mg), S, B, and Zn were all deficient. Citrus yield fell by 67% without Mg, 27% without S, 10% without B, and 78% without Zn, compared to the BF treatment which produced 8.94 kg orange fruit/tree. Guangxi-NMS02