缓坡水平梯田土壤水分空间变异性

Spatial variability of soil moisture in horizontal terrace on slightly sloping land

以江苏省扬州市区北部某梯田为例,分析了小于2°的缓坡水平梯田土壤含水率的空间变异特征,并针对缓坡水平梯田土壤含水率由较高田块到较低田块逐渐增加、同一级梯田内由内侧到外侧含水率逐渐减小的分布特征,提出了适合研究该种地形土壤含水率空间分布的有效方法,即趋势辅助克立格法(简记为KTAI)。该方法同时考虑了不同级梯田高程和同级田块内不同部位对土壤含水率的影响,用它对梯田土壤含水率进行插值,估计方差比传统的普通克立格法(简记为OK)大幅度降低,大大提高了估值精度,减轻了野外采样工作量,对于研究梯田土壤水分空间变异性具有重要意义,同时拓展了地质统计学理论在土壤水分空间变异性研究中的应用范围。

Taking a horizontal terrace on a slightly sloping land with a gradient less than 2°in northern Yangzhou,Jiangsu Province for example,spatial variability of soil moisture in the terrace was analyzed.Soil moisture of a terrace on the upper level is higher than that of the lower one,and soil moisture of the inner side is higher than that of the outside in the same terrace.Based on the distribution of soil moisture,an effective method named Kriging using trends as auxiliary information（KTAI）was proposed.The method taking into account the effects of both elevation of different terrace levels and different locations of the same level terrace on soil moisture,was used to interpolate the soil moisture in terraces.KTAI is useful for studying spatial variability of soil moisture in terraces and extending the application of geostatistics in spatial variability of soil moisture.