沂蒙山区桃园棕壤斥水性对理化性质的空间响应

以沂蒙山区典型土地利用桃园棕壤为例,在分析降雨前后桃园棕壤斥水性与理化性质空间变异的基础上,探讨了棕壤斥水性对土壤含水量、有机质含量和土壤质地的空间响应特征。按照1 m×1 m网格等间距测定降雨前后土壤实际斥水性与含水量,同时采集表层0~3 cm土壤样品,分析其有机质含量与砂粒、粉粒、黏粒含量,并借助经典统计学、地统计学与空间自相关理论对土壤斥水性及理化性质进行空间格局与空间相关性分析。结果表明:沂蒙山区桃园棕壤的斥水程度强烈,雨后斥水性显著降低;降雨前后棕壤斥水性均具有中等变异水平和较强的空间自相关性,且呈指数模型分布,各向异性显著。受结构变异和随机变异作用,斥水性空间格局沿耕作方向呈条带状分布,在其垂直方向上最小变程为1.4 m。土壤质地是影响棕壤斥水性空间变异的主要因素,斥水性与粉粒含量呈空间正相关,与砂粒和黏粒含量呈空间负相关,相关程度粉粒砂粒黏粒;棕壤斥水性与含水量呈空间负相关,相关度雨前较弱,雨后显著。

Spatial response of water repellency to physicochemical properties in peach (Prunuspersica) orchard brown soil in Yimeng Mountains

Peach(Prunuspersica) orchard is a type of land use typical of brown soil in the Yimeng mountains. Soil water repellency(SWR) and soil physicochemical properties, such as soil moisture, soil organic content and soil texture, in the peach orchard brown soil before and after rainfall were analyzed to explore spatial response of SWR of the soil to variation of its physicochemical properties. Soil moisture content and SWR was measured in-situ and a total of 100 topsoil samples were collected, too, in a 1 m×1 m grid pattern for analysis of contents of soil organic matter, sand, silt and clay. On such a basis, classic statistics, geostatistics and spatial correlation analysis were coducted. Results show that the SWR in studied brown soil was strong under the condition of lasting drought and decreased significantly after rainfall, and the SWRs before and after rainfall were both moderate in variability and strong in spatial autocorrelation, showing an exponential pattern in distribution with significant anisotropy. Under the joint function of structural and random variations, especially the structural variation, spatially the SWR was distributed in band following the direction of ploughing and its minimum codomain in vertical direction was 1.4 m. Soil texture was the main factor influencing spatial variability of SWR: SWR was positively related with silt content, but negatively with sand and clay contents in spatial distribution, showing an order of silt > sand > and clay in degree of spatial correlation with SWR. SWR was also negatively related with soil moisture in spatial distribution. The negative relationship was quite weak before rainfall and became significant after rainfall.