作物水模型参数与时段数关系的研究

Research on the Parameter and Number of Periods of Crop Response to Water

时段划分是影响作物水模型参数求解和应用的一个重要因素。依据山西水利职业技术学院试验基地2007和2008年度冬小麦田间试验资料,将冬小麦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模型参数,分析研究了模型参数与时段数的关系,据此在水分敏感指数累积函数中引入了时段数,并与模型1(未引入时段数)进行了比较分析。结果表明,模型2(引入时段数)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13时,相对误差平均值和最大值即分别减小到11%和20%以下;与模型1比较,参数个数未增加,模拟精度未降低;可用于任意时段数条件下的产量模拟计算,更精确地反映了水分胁迫时间对作物产量影响的信息。

The application of model of crop response to water is affected significantly by period division.Based on the experiment data obtained in 2007and 2008,parameters were solved with nonlinear programming by interval period division in the growing period of winter wheat.The relationship between parameters and the number of periods is analyzed.The model of crop response to water is modified based on the number of periods introduced to cumulative function of sensitive index.The comparison of model-2（the function with number of periods） and model-1（the function without number of periods） shows the relative error of simulating yield is reduced with the number of periods increase for model-2.When the number of periods is bigger than 13,the average of relative error and the biggest value are respectively reduced to 11%,20%.Compared to Model 1,the number of periods does not increase and the simulation accuracy does not decrease for Model 1,indicating that Model 2 performs well in simulating yield in any period numbers.It can reflect the yield affected by the time of water stress accurately.