泾惠渠灌区渠道衬砌对土壤有机质的影响及其空间变异性

Effects of canal lining on soil organic matters in Jinghuiqu Irrigation District and their spatial variability

为了解灌区渠道衬砌节水对土壤质量的影响,以陕西关中典型灌区泾惠灌区为研究对象,综合运用传统统计学、地统计学和GIS技术,研究了泾惠渠灌区干支渠衬砌渠道两侧土壤有机质(SOM)空间变异及土壤颗粒分布特征.结果表明:衬砌渠道两侧SOM质量比介于18.96~162.92 mg/kg,平均为86.07 mg/kg,其中,预制混凝土衬砌渠道两侧SOM质量比最高,现浇凝土衬砌和浆砌石衬砌其次,复合土工膜衬砌最低;地统计分析表明,研究区SOM的半方差函数可用指数模型进行最优拟合,变程为21.7 km,结构方差占总方差的比例为0.37,SOM表现出中等程度的空间依赖性,SOM质量比和土壤颗粒的kriging插值图表明,两者具有显著空间相关性.SOM的空间分布格局是随机性因素和结构性因素共同作用的结果.

In order to fully understand the impact of water-saving irrigation canal lining on soil quality, spatial and temporal variation characteristics of soil organic matter（SOM） and soil particles in both sides of lining canals are investigated in trunk and branch canals Jinghuiqu Irrigation District, Shaanxi Pro- vince by using traditional statistics, geostatistics and GIS. The results show that SOM in both sides of lining canals is 18.96 - 162.92 mg/kg with an average of 86.07 mg/kg, particularly, SOM is the maximum for cast-in-place concrete lining canals, and is the minimum for composite geomembrane lining cannels, is in between for masonry ling cannels. Based on a variogram analysis the semivariance function of SOM can be best fitted by using an exponential function with a 21.7 km range. The spatial covariance has a second-order trend and anisotropy on the spatial variability in the study area; and the spatial heterogeneity, caused by the relevant part of the overall spatial variability, accounted for a smaller proportion, presenting of moderate dependence on space and belonging to moderate variability. Using the ordinary kriging interpolation method, the spatial distribution of SOM and soil particles are obtained; and the characteristics of the spatial distribution and influencing factors are analyzed.