时段划分对棉花作物水模型的影响与改进

为了改善时段划分对作物水模型模拟精度的影响，依据山西水利职业技术学院试验基地2006和2008年棉花田间试验资料，将棉花全生育期等间隔地划分为不同时段，用非线性优化方法求得了不同时段数条件下的作物水模型参数，分析研究了模型参数与时段数的关系，据此在作物水模型的水分敏感指数累积函数中引入了时段数，并与现有的作物水模型进行了比较。结果表明，引入时段数的作物水模型模拟产量的相对误差随时段数的增加而减小，当时段数大于11时，相对误差平均值和最大值分别减小到7%和15%以下，与现有的作物水模型比较，模拟精度有所提高，但参数个数未增加。该模型更多地反映了水分胁迫时间对作物产量影响的信息。

Effect and improvement of period division on model of cotton crop response to water

To improve the model simulation accuracy of crop response function to water, the modified model of cotton crop response to water was established based on the experimental data obtained in 2006 and 2008. Parameters of cotton crop response to water were solved with nonlinear programming by interval period division in growing period of cotton. The relationship of parameters and the number of periods was analyzed. The model of crop response to water was modified by introducing the number of periods into cumulative function of moisture sensitive index, and was compared with the existing model of crop response to water. The results showed that the relative error of yield simulation by modified model was reduced with number of periods increasing. When the number of periods was more than 11, the average of relative error and the biggest value were respectively reduced to less than 7% and 15%. Compared with existing model, the number of parameters was not increased and the simulation accuracy was improved for modified model. It shows that the modified model perform better for yield simulation with any period number and can accurately reflect the change of yield by the water stress time.