反求根系吸水速率方法的检验与应用  

Accuracy and stability of the inverse method to estimate the average root-water-uptake rate and its application

作　　者：左强[1] 王东[1] 罗长寿[1] 

机构地区：[1]中国农业大学

出　　处：《农业工程学报》2003年第2期28-33,共6页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家重点基础研究发展规划项目 (G1 9990 1 1 70 9) ;国家高技术研究发展计划 (863计划 ) (2 0 0 1 AA2 4 2 0 31 ) ;霍英东高等院校青年教师基金项目

摘　　要：土壤含水率剖面实测时间间隔 T与实测点间距 SI是影响平均根系吸水速率反求方法的 2个主要因子。通过数值实验 ,首先探讨分析了 T和 SI的不同取值条件下 ,平均根系吸水速率模拟值的误差效应 ,从实际应用角度出发 ,若设定平均根系吸水速率的最大绝对误差≤ 0 .0 0 15 d- 1 ,总体相对误差≤ 15 % ,则 T和 SI的选取最好能限制在如下范围之内 :5 d≤ T <15 d,SI <2 0 cm。应用上述检验分析结果 ,对两种水分胁迫条件下土柱实验中苗期冬小麦的根系吸水进行了模拟分析 ,结果表明 :持续的水分胁迫将显著地降低冬小麦根系的吸水速率 ,抑制其根系的生长 ;当上部土层水分供应不足时 ,小麦的自我调节功能可导致根系扩大其吸水范围 ,向下部土层生长。The accuracy and convergence of the inverse method to estimate the average root water uptake rate, which was proposed by Zuo, et al.(2001), are mainly dependent on the following two factors: the time interval (T) between the two successive measurements of soil water content distributions, and the spatial interval (SI) of the measured data along the soil profile. Examples of the numerical experiment were taken to examine the effect of different T and SI on the accuracy and stability of the method in this paper. In practice, it is recommended to choose 5 d≤T<15 d and SI<20 cm so as to keep the maximal absolute error and the overall relative error between the estimated and the real average root water uptake rate within 0.0015 d -1 and 15%, respectively. Furthermore, the inverse method was applied to simulate the average root water uptake rate distributions of winter wheat at seedling stage under water stress. Winter wheat was planted in the soil columns and the experiment was conducted in a greenhouse with 2 water stress levels. The simulated results showed that water stress reduced root water uptake of winter wheat remarkably and probably inhibited the roots growth as well. The scope of winter wheat root water uptake was adjusted by itself to the lower soil layer where soil moisture was appropriate when soil water supply in the upper soil layer was deficient.

关 键 词：平均根系吸水速率 土壤水 反求方法 数值模拟 

分 类 号：S607[农业科学—园艺学] S318