Research On Models Of Farmland Nutrient Balances And Decision Support System

The balance models on the relationships between soil elementary nutrient conditions, fertilization and biomass, economic yield, nutrient contents in crop plants as well as soil nutrient changes after crop harvest were developed through the field experiments and data collection under single-nutrient and multi-nutrient limited conditions. The models considered the relation of soil and climate, which would widen the applicable scope of the models. The models were tested with the data of the experiments, indicating that the correlation coefficients between the simulated and observed values were all at significant level. The nutrient dynamics under different yield levels and different management patterns in Xiangshui country and Lixiahe region in Jiangsu Province were analyzed by the developed models. Avoiding the errors resulting from the adoption of the average values of nutrient content in crop plants, the nutrient balance models raised the accuracy in nutrient management of crop production.Soil fertility, which influenced the target yield and fertilizer recommadation, was the premise conditions of developing nutrient decision support system. Therefore an evaluation method of integrated soil fertility with fuzzy math and analysis hierarchy was developed, with 10 indexes being selected. The integrated soil fertility values in Xiangshui country of Jiangsu Province were calculated. The results showed that the soil fertility of large parts of the farmlands in this region was at middle or low levels.Soil-fertilizer-crop-administration zone maps were integrated by GIS, and farmland nutrient decision support system was developed on basis of nutrient balance models, which could serve as quantitative and long prediction of nutrients and multi-goal decision making for nutrient mangement. The system running depended only on inputs of crop characteristic parameters, main soil properties and climate conditions, but needn't change the structure of the decision system and therefore the generality of the system was reinforced.