基于水分平衡原理的内蒙古典型草原土壤水动态模型研究

Establishing soil water dynamic model for typical steppe based on water balance principle

建立水分平衡动态模型是研究草原生态系统水循环的主要方法和内容。本文利用锡林浩特观象台多年观测资料和2008～2009年野外试验资料,基于SPAC原理,依托农田水分平衡方程建立了0～100 cm土层的土壤水分平衡模型,提出初始土壤贮水量、实际蒸散量、渗漏量和植被截留量等参数的计算方法及植物根系层深度确定的依据;通过2008～2009年实测资料的验证,平均相对误差8.2%,变幅0.3%～23%,经t检验未达到0.05的显著水平,所建模型可以用来描述典型草原区水分平衡和进行土壤水分模拟计算,为动态监测土壤水分变化和开展草原干旱监测预测工作提供方法。

Establishing model of water balance dynamic is a main research method and content in the study of water cycle of grassland ecosystem.By using data of meteorological observation and field experiment of water at Xilinhot Climate Observatory in 2008～2009,model of water balance of 0～100 cm soil layer was set up with water balance equation of farmland and SPAC principle.The method to calculate the parameters of initial soil water storage,actual evapotranspiration,infiltration capacity,and vegetation interception were put forward through the research,and the rules for root depth identification was obtained,too.It was showed that the model was good at soil water simulation in the test（the average relative error was 8.2%;the fluctuation range was at 0.3%～23%;the significance level of T-test was less than 0.05） with data of actual observation in 2008～2009.Based on this we conclude that the model was an approptiate measure for monitoring soil water changes and for forecasting grassland drought in steppe zone.