根系水分胁迫响应函数对土壤水及作物生长动态和产量模拟影响的研究

为探究根系水分胁迫响应函数对农田水分动态及产量模拟的影响,基于Richards方程和PS123作物生长模型分别进行了土壤水分动态和小麦产量的模拟,对比分析了VG(S型曲线)、MP(凹凸型曲线)及LS(S型曲线)3种水分胁迫响应函数.采用山西省霍泉站(3 a)及潇河站(2 a)的试验资料对模型中的土壤水力特征参数、水分胁...

Effect of root water stress response function on soil water,crop growth dynamics and yield simulation

To investigate the effect of the root moisture stress response function (RMSRF) on soil moisture dynamic and yield simulation, the soil moisture dynamic, and wheat yield were simulated based on the Richards equation and PS123 crop growth model. The three RMSRF of VG (S-curve), MP (convex curve), and LS (S-curve) were compared. The soil characteristic and RMSRF parameters in the model were inverted to determine the optimal parameter values using the measured data from Huoquan Station (three years) and Xiaohe Station (two years) in Shanxi Province, China to obtain the simulation results of soil moisture content, evapotranspiration, and grain yield. The analysis is as follows. (1) The soil moisture and yield simulations under VG, MP, and LS functions are good. The RMSE value is between 0.021 and 0.036; the r test between the simulated and measured values has reached an extremely significant level. For the Huoquan Station, under the three RMSRF of VG, MP, and LS conditions, the average relative errors of the simulated and measured values for soil moisture content are 6.37%, 8.26%, and 7.18%, respectively. The minimum certainty coefficient value is 0.7814. The average relative error values of the simulated wheat yield are 8.73%, 8.40%, and 8.42%, respectively. For the Xiaohe Station, the average relative error of the simulated and measured values for soil moisture content is greater than that of the Huoquan Station, with a maximum of 12.47%. (2) The simulation of soil moisture dynamic shows that RMSRF by the S-shaped curve shows better results than RMSRF by the concave-convex curve. The average relative error using the VG function is smaller, and the simulated evapotranspiration is closer to the actual measurement. (3) In terms of yield simulation results, there is no significant difference among the three RMSRF. In summary, the VG function is a high-precision RMSRF, and the model is simple and convenient. The suggested LS function can improve the simulation accuracy, but the stability of the model needs further research.