基于土壤-作物系统模拟模型的冬小麦田间水氮优化管理

Optimal management of water and nitrogen for winter wheat based on simulation model in soil-plant system in agricultural field

将作物生长模型与土壤水氮管理过程模块相结合,构建了土壤-作物系统水分养分模拟模型。以灌水、施氮总量为决策变量,冬小麦生物量、水分和氮肥利用效率为优化目标,将冬小麦按生长发育时期分为6个阶段,建立了多目标的动态规划模型。在土壤-作物系统过程模型的基础上,用动态规划的方法对田间水、氮资源管理措施进行优化。通过对作物水分胁迫系数和氮肥胁迫系数的模拟计算,可获得最佳的灌水、施肥时间及用量。算例结果表明:在养分供应充足仅水分胁迫的条件下,优化方案的灌水量较对照处理平均节约了25%,水分利用效率比对照处理平均高出约12%。在水分和养分均胁迫的条件下,优化方案的灌水量较对照处理平均节约了12%,水分和氮肥利用效率分别比对照处理提高了约13%和16%。

The paper introduced the development of a process model that used for water and nutrients management in soil-plant system by integrating the crop growth module in PS123 model and the soil water and nitrogen dynamic process module. The growth season of winter wheat was divided into six stages, taking the total amounts of irrigation and nitrogen application as the decision variables, the biomass of winter wheat, water and nitrogen use efficiency （WUE） were selected as the optimal objectives, then a multiple-object dynamic programming decision model was developed based on the process model in soil-plant system. The decision model was employed to optimize the management scenarios of irrigation and nitrogen application for winter wheat. Through calculating the crop water and nitrogen stress index, the optimal time and amount of water and nitrogen management were obtained. The results indicated that the irrigation amount had a 25 % reduction on the average compared with the control, and the WUE increased by 12% compared with the average of control treatment under the condition of water stress （PS2 level）, while under the condition of water and nitrogen stress （PS3 level）, the irrigation amount had a 12% reduction on the average compared with control, and water and nitrogen use efficiency had a 13% and 16% increase compared with controls, respectively.