时域反射仪对水分非均匀分布土壤含水率的测定  

Measurement of soil water content by time domain reflectometry in non-uniformly wetted soils

作　　者：李子忠[1] 郑茹梅[1] 龚元石[1] 王一鸣[2] 杨新明[1] 王克栋[2] 

机构地区：[1]中国农业大学资源与环境学院,北京100193 [2]中国农业大学信息与电气工程学院,北京100083

出　　处：《农业工程学报》2010年第11期19-23,共5页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家高技术研究发展计划(2006AA10Z264)

摘　　要：为了评估时域反射仪测定水分非均匀分布土壤的含水率的性能,该研究在室内试验中将土柱纵向分为上下2层,设置土壤水分差为0.05、0.10和0.15cm3/cm33种情况,进行不同含水率梯度下水分非均匀分布对该仪器测定土壤含水率的影响试验,并在田间试验中进行了实地测试。结果表明,在室内新型时域反射仪随着上下2层土壤含水率梯度差的增加,测定土壤含水率的均方根误差略有增大,在水分分布相对均匀的土壤中测定土壤含水率的均方根误差小于0.028cm3/cm3。在田间竖直埋设探头,上湿下干和上干下湿的土壤含水率差异范围分别在0.011～0.026和0.026～0.064cm3/cm3时,仪器测定含水率的均方根误差分别是0.037和0.027cm3/cm3。时域反射仪测定水分不均匀分布情况下的土壤含水率是可行的。In order to evaluate the performance of a newly developed time domain reflectometry（TDR） by measuring soil water content in the non-uniformly wetted soils,soil column was vertically divided into two layers in the laboratory,and the differences of soil water content between upper and lower layers were designed as 0.05,0.10,and 0.15 cm3/cm3,and soil water content was measured under the conditions of different water content gradients,furthermore,the field test was also conducted to study the performance of the reflectometry in the non-uniformly wetted soils. Results showed that the new TDR could be used for measuring soil water content in the non-uniformly wetted soils and the root mean square error（RMSE） was less than 0.028 cm3/cm3. The RMSE increased as the differences of soil water content between upper layer and lower layer increased in the laboratory experiments. In field,when soil water content gradients of wet/dry and dry/wet were 0.011–0.026 and 0.026–0.064 cm3/cm3,the RMSE was 0.037 and 0.027 cm3/cm3,respectively. The new TDR instrument can be used for measuring water content accurately in the non-uniformly wetted soils.

关 键 词：时域分析 仪器 评估 土壤含水率 非均匀 

分 类 号：S151.9[农业科学—土壤学]