基于对SPAC系统的认识,以1995～1996年北京市水利科学研究所永乐店试验站和1993～1994年中国科学院禹城综合试验站冬小麦生长季土壤-作物-大气田间观测数据,对冬小麦根系层水量平衡的概念性模型进行参数确定和实验验证。研究结果表明:本文采用的根系层储水量的预测模型的模拟值与实测值吻合较好,且模型参数较少,形式简单,便于生产实践应用,但是具体的参数须通过田间试验获得。

Based on the knowledge of the SPAC system, a conceptual model of water balance in winter wheat root zone was set up. The model assumed vertical flow of water only. The evapotranspiration was estimated by combining the reference evapotranspiration, crop coefficient and soil water stress coefficient. The crop coefficient is the function of crop LAI, and the soil water stress coefficient is the function of soil water content. The lower boundary flux was modeled as a function of soil water storage in the root zone empirically. Fundamental data required to run this model included the daily meteorological data, soil properties (such as soil type, wilting point and field capacity), the irrigation data, the initial values of soil water storage in root zone, LAI of crop, and the some other empirical parameters involved. The empirical parameters should be calibrated prior to the model application. Empirical parameters in the model were calibrated firstly and the model was validated independently with the winter wheat plot test data in Yucheng Station and Yongledian Station. The results showed that the simulated values by the model agreed well with the measured ones. This model contains only a few parameters and is simple in form. So it can be easily adopted in field water management. When it is used, prior calibration of the parameters in the model should be done with the field data.