Nutrient Management Strategies for Hainan

Meilan County and the state-owned Nanbin Farm in Hainan were selected to determine local soil nutrient status and existing nutrient variability with the goal of developing site-specific nutrient management techniques capable of sustaining improved crop yields and farmers’ profit. Field trials and fertilizer use survey data will be applied to a national information systems database which we envision will assist decision-making by both industry and government. In addition, the study provides much guidance for developing fertilizer recommendation and nutrient management systems for these two locations.

Nitrogen (N), potassium (K), and phosphorus (P) are the major yield-limiting factors in Meilan County. Deficiency for N, K, and P represented 94%, 45%, and 26% of the total soils sampled, respectively. Soil fertility at Nanbin Farm was much lower as all samples were deficient in N and magnesium (Mg), 94% were deficient in calcium (Ca), 93% deficient in sulfur (S), 78% deficient in copper (Cu), and 58% deficient in P. Potassium deficiency is not a major factor (14.7% of soil samples were K deficient), as the state-owned farm has been using K fertilizers for the past 10 years. These results will be verified through field trials in 2004. Hainan-NMS01