反求根系吸水速率方法的探讨  

Approaches to Simulating Root Water Uptake Rate by Solving Inverse Problem of Richards' Equation

作　　者：左强[1] 王数[1] 陈研[1] 

机构地区：[1]中国农业大学

出　　处：《农业工程学报》2001年第4期17-21,共5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"(项目编号G19990 1170 0 );"中国-以色列科学与战略研究开发专项资金合作研究项目"资助的部分研究

摘　　要：植物生长条件下土壤水分运动方程的逆问题具有强烈的非线性性与不适定性 ,该文探讨分析了两种现有的模拟根系吸水速率的反求方法 ,并提出了一种新的数值迭代反求方法。数值实验结果表明 :含水率 (或基质势 )剖面实测值与模拟值的对比不足以论证根系吸水模型的正确与否 ;当初始剖面土壤水分变化较为剧烈时 ,提出的新的数值迭代反求方法可以较好地模拟根系吸水速率在土壤剖面上的分布 ,在任意两次“实测”时间间隔内 ,当根系吸水速率变化不大时 ,选用时间间隔分别为 1、2、5、10和 15 d的“实测”土壤水分剖面均可以获得与理论吸水分布较为一致的结果 ,模拟所得的“实际”蒸腾强度与理论值的相对误差均在The inverse problem of Richards' equation incorporating plant water use is strongly nonlinear and improperly posed. Two present approaches to simulating root water uptake rate by solving the inverse problem of the equation were discussed, and a new iterative numerical method was developed. Two numerical experiments were conducted to demonstrate the uncertainty of root water uptake functions for simulating soil water flow. The result accuracy and the stability of the approaches were testified, respectively. The results show that the comparison between the measured and the simulated soil moisture content profiles is not enough to indicate the accuracy of the root water uptake function. The two present approaches could not be used to simulate water uptake rate by roots when the hydraulic gradient (including its direction and/or values) changed greatly in the profile, whereas the new proposed method was able to give a satisfied result——all the simulated water uptake rates in different time intervals between two successive measurements such as 1, 2, 5, 10 d and 15 d matched the real values well when the theoretical uptake rate was almost constant with time. The relative errors between the simulated and the actual transpiration rate in different time intervals were not more than 3%.

关 键 词：根系 吸水速率 土壤水 Richard方程 逆问题 数值模拟 迭代方法 

分 类 号：S318[农业科学—作物栽培与耕作技术] S152.72[农业科学—农艺学]