巴拉格尔河流域土壤传递函数构建与评估

Construction and evaluation of pedo-transfer functions in the Balager River Basin

以土壤理化性质数据建立传递函数是间接获取土壤水力参数的重要手段。采集巴拉格尔河流域土壤0~30 cm和30~60 cm土层102个样品,测定粒径分布、干容重、有机质、饱和导水率、田间持水率等指标,利用数理统计、空间插值及主成分分析等方法揭示流域根系层土壤理化及水力特性空间特征,以土壤饱和导水率(KS)为例对多种土壤传递函数模型进行适用性分析,结果表明:(1)以砂质壤土为主,随根系层土壤深度加大,砂质壤土含量减小,壤质砂土增多;(2)不同层饱和导水率空间分布具有相似性,土壤深层大于表层的KS;(3)土壤根系层30~60cm土层的新建传递函数模拟效果较好,检验参数r、δME和δRMSE分别为0.73、0和1.62;(4)估计误差的大小与土壤类型有关,新建PTFs对于砂质壤土较为适用。

It is important to understand the soil characteristics of the grass root layer for the restoration and protection of the grassland ecosystem.The pedo-transfer functions(PTFs)based on soil physical and chemical property data were the primary means to indirectly obtain soil hydraulic parameters.The Inner Mongolian Balager River Basin was selected as the typical study area,and 102 soil samples were collected in the depths of 0 to 60 cm of the grass roots.The indices of soil physical,chemical,and hydraulic characteristics were tested,including particle size distribution,dry density,organic matter,saturated hydraulic conductivity,and water-holding capacity.Kriging and principal component analysis were used for revealing the spatial pattern of the soil physical,chemical,and hydraulic characteristics parameters in the plateau inland grassland basin.Taking soil saturated hydraulic conductivity(KS),for instance,the transfer functions were built and validated.The results showed that(1)sandy loam was the main soil,and sandy loam content decreased and loamy sandy increased with the soil depth increasing in the study area;(2)KSspatial distribution of different soil layers was similar,and the KSof deeper layer soil was bigger than that of the surface layer;(3)the simulation effect of the new transfer function was better in depths of 30-60 cm of soil layer,and ther,δME,andδRMSE were 0.73,0,and 1.62 respectively;and(4)the calculated error was related to the soil type,and the new PTFs of sandy loam was better than loamy sandy.