Study On Decision Support System For Maize Nutrient Management

The implementation of variable rate fertilizer applicator for precision agriculture technology is one of the important contents, arguing that under the small-scale Field between the differences in soil fertility and crop growth, subject to different amounts of fertilizer, which can reduce the use of fertilizer, improving the utilization of fertilizers, and from the reduce the overall non-point source pollution. At present, variable rate fertilization research focused on soil fertility and objectives based on output or remote sensing data, but the limitations of the system or due to the high prices, or applied to the production of small.In 2007 ~ 2009 in Wen County agricultural basis of the test, build a model of variable rate fertilization of corn and nitrogen, phosphorus and potassium stress test on the system, results show that:Firstly, Based on the ecological environment in Wen County, in the N, P, K, under appropriate conditions, growth stage and yield higher accuracy of simulation, simulation of the value of the whole growth period with the only difference between the actual observed values 1 ~ 2d, jointing stage and heading phase difference between the larger, respectively, for 3 ~ 6d and 0 ~ 4d, LAI, dry matter weight of the simulated and measured values match, the correlation coefficient reached 0.9008 ~ 0.9876; output analog value and the measured value of the difference between 5.5 ~ 50.6kg / acre. However, nitrogen stress conditions, simulation significant error.Secondly, In accordance with the principle of nutrient balance and "crop - soil - environment - technology" principle, build a model of variable rate fertilization of corn, including corn before sowing nitrogen, phosphorus and potassium fertilizer and sowing the total after the amount of nitrogen topdressing accurate. The spatial information technology to the soil data and the volume of corn to be fat and reproductive stages combined leaf area, through the leads to the revised crop factor, the initial value of the fertilizer be revised in order to determine the different maize varieties at different growth stages of the optimum dressing volume. This reduction of fertilizer application method of the waste and the pollution of the environment for fertilization of corn production to provide a scientific and reasonable guidance. Thirdly, The adoption of N, P, K fertilizer revised model, groups of corn production model of the photosynthetic N, P, K prime factor revision and testing. The results showed that: the revised canopy photosynthetic production model can better simulate the N, P, K, under stress conditions the growth of maize and yield formation of fat. Less than in the fertilizer and excessive conditions, the simulation of leaf area and measured the value of a correlation coefficient of 0.8514 ~ 0.9876, dry weight of the correlation coefficients were 0.9017 ~ 0.9802, the output correlation coefficient of 0.9102. From the trend analysis, Shi N under the conditions of inadequate or excessive, LAI and dry matter accumulation and nitrogen Phase optimal consensus on a revised model of the structure of nitrogen reasonable parameters accurately, after nitrogen, phosphorus, potassium factor model revised Wen County can better meet the needs of maize production.Fourthly,2007 ~ 2009 in Wen County applied agricultural corn-based variable rate fertilization decision-making system, to verify the validity of the model. The results showed that: the simulation model output correlation coefficient 0.9102 and 0.9424, respectively, reaching significant levels. And variable rate fertilization in the model of the operation under the guidance of the average nitrogen application rate with the local conventional nitrogen, the results showed that production at the same level, every little Shih hm2 Pure 25.1kg, indicates that the system has saved costs and increase efficiency and the role of pollution prevention and control.