土壤紧实度估算G-A模型参数的空间变异分析

Spatial variability analysis of soil infiltration by calculating simplified G- A infiltration parameters using soil compaction

为了分析土壤入渗空间变异特征并为灌溉系统设计和管理提供依据,基于土壤初始重量含水率、土壤紧实度、土壤黏粒含量和入渗过程数据,利用多元线性回归方法,分析选用土壤紧实度对简化的G-A入渗模型参数进行估算的合理性;通过半方差函数分析,进一步探讨了不同畦田规格下土壤入渗空间变异特征.结果表明:土壤紧实度与土壤质地、结构和含水率关系密切,在与土壤入渗参数的回归关系中达到了系统的显著性要求,采用其对简化的G-A入渗模型参数进行估算是可行的;畦田规格由0.5 hm2扩展到3.0 hm2时,简化的G-A入渗模型参数的变异系数均在0.1~1.0,空间变异程度呈中等,空间结构具有中等相关性,且都可用球状模型进行描述,畦田规格差异对G-A入渗模型参数空间变异程度和空间结构影响不具有统计学意义.

In order to analyze the spatial variability of soil infiltration and provide guidance for irrigation system design and management,based on the observed data of initial water content,soil compaction,clay content and soil infiltration at typical points,the rationality of calculating simplified G- A infiltration parameters using soil compaction were analyzed by means of multiple linear regression method. Furthermore,spatial variability of soil infiltration was also discussed using semi-variance analysis at different basin sizes. The results show that there is a high correlation among soil compaction,soil texture,soil structure and soil water content,meanwhile satisfactory significance was reached in its regression relevance with soil infiltration parameters. Thus it is feasible to calculate simplified G- A infiltration parameters using soil compaction. When the basin size expanded from 0. 5 hm2to 3. 0 hm2,the variation coefficient of G- A infiltration parameters were between 0. 1 and 1. 0. Medium spatial variability of G- A infiltration parameters were found at different basin sizes. The semi-variogram of G- A infiltration parameters could be described by spherical model,and the spatial structural correlation were medium. No significant differences in spatial variation of infiltration parameters were found among different basin sizes.