作物生长条件下蒸发与蒸腾的模拟及土壤水份动态预报

以由能量平衡原理及边界层水汽扩散理论而导出的Ｐｅｎｍａｎ－Ｍｏｎｔｅｉｔｈ公式为基础，确立了棵间潜在蒸发及潜在植株蒸腾的计算模式．建立了以作物根量分布为基础的根系吸水模型．结合实测资料，导出了棵间实际蒸发的经验模式．应用上述经验与半经验模型，结合非饱和土壤水份运移方程，对田间土壤水份动态进行了模拟与预测，其结果与实测结果拟合较好．

Simulating Evaporation and Transpiration and Forecasting SOil Moisture Regime under Conditions of Crop Growth

Evaporation and transpiration are the most driportant parts of water transport in SPAC system. Methods for estimating potential evaporation a.ud potential transpiration are presented in this paper, based on the Penman-Monteith model and crop canopy cover. The relationship between root density of corn and its depth can be appoximated by an exponential function. According to this relationship, a corn root uptake water model is derived. Field experiment data show that the ratio of actual evaporation to potential evaporation varies linearly with average moisture content of surface layer soil. All above semi-empirical models are incorporated with the pressure bend based water transport model of SPAC system, and the Crank-Nicolson finite difference scheme is used to solve the model. The model has been adopted to simulate and predict soil moisture regime of corn field. The simulated and predicted soil water pressure is consistent well with the experimental data.