Model Selection And Parameters Estimation In Soil Testing And Fertilizer Recommendation For Cultivation Of Chili(Capsicum Annuum): A Case Studied In Hoxud County

To accomplish the purpose of model selection and parameters estimation in soil testing and fertilizer recommendation for cultivation of chili(Capsicum annuum),twenty-four “3414” fertilizer experiments were conducted in four villages of Hoxud County in Xinjiang Uygur Autonomous Regions in 2011-2012. The “3414” fertilizer experiments indicated the experiment included three nutrients(nitrogen, N;phosphorus, P; potassium, K) and each of nutrients included four fertilized levels(i.e, N0, N1, N2 and N3). Then, a total of fourteen fertilized treatments were selected to assess the best fertilized model and estimate its parameters for cultivation of chili. The key findings are as follows:(1) A ternary quadratic multimonial fertilizer function and a quadratic equation of one unknown fertilizer response function were established based on the data that obtained from the “3414” fertilizer experiments, which described the maximum production of chili could be harvested and the best fertilizer amount should be applied in order to reach the maximum economic production in Hoxud county.(2) The levels of 2.71 kg N(urea), 0.9 kg P(calcium superphosphate) and 2.3 kg K(Potassium sulphate) were required to reach the production of 100 kg chili in Hoxud county.(3) Some corrected models in soil nutrient availability were also established in Hoxud county for cultivation of chili. Particularly, the relationship between N availability(y) and alkali-hydrolyzable N(x) could be expressed as y=0.8742e-0.005 x.The relationship between P availability(y) and available P be expressed as y=2.5588e-0.04 x. The relationship between K availability(y) and available K could be expressed as y=1.0075e-0.004 x.(4) The utilization rate of N(urea), P(calcium superphosphate) and K(Potassium sulphate) were 44%, 22% and 47% in Hoxud county for cultivation of chili.