伊犁河谷土壤理化性质及可蚀性特征分析

Feature analysis of soil physicochemical properties and erodibility of the Yili Valley

探讨河谷坡地的土壤特性及其可蚀性对保护土地资源、制定水土保持措施具有重要意义。基于伊犁河谷典型区域127个调查点表层土壤的实地调查与取样分析,利用EPIC模型公式计算土壤可蚀性,分析了不同土地利用方式下土壤理化性质及土壤可蚀性的特征、探讨了土壤可蚀性与其他土壤特征因子间的关系以及土壤各特征因子的空间变化与异质性。研究结果显示:新开垦坡地增加了表层土壤水分、改善了土壤结构与质地,有助于减小土壤可蚀性;土壤理化性质随着海拔升高、由西南向东北明显改善,土壤可蚀性降低,质地更好的土壤有助吸水、保水与植被生长,进而降低土壤可蚀性;各土壤特性,包括土壤可蚀性,空间异质性在小尺度上总体较小,空间分布自相关程度多中等到高等。

The large scale exploitation of water and land resources in the Yili River Valley in recent decades is the background for this work. The exploitation has mainly been concentrated in the piedmont slope of the valley and this may have affected soil properties and erodibility. Research on soil properties and erodibility can help conduct better prospection of land resources,and develop effective soil and water conservation measures. We selected the piedmont slope of the valley as the research focus and conducted an investigation based on field surveys,sampling and experimental analysis. A typical area of piedmont slope with 400km^2 and 127 survey points was selected in order to obtain soil properties. Experience estimation formula of the EPIC model was used to get soil erodibility. This work analyzes the soil properties and soil erodibility under different land use patterns,tests the relationship between soil erodibility and each soil characteristic factor,and analyzes the spatial heterogeneity of soil properties and soil erodibility. We found that newly reclaimed fields increased soil water content,improved soil properties and structure,to some extent,and contributed to reducing soil erodibility. Soil N content and soil organic materials show an obvious decline in newly reclaimed fields than circumjacent uncultured areas. From southwest to northeast the soil becomes better with increasing altitude,such as lower soil bulk density,higher soil organic materials and N,and higher soil water content;soil erodibility is gradually declining.There is a close relationship between soil physicochemical properties and soil erodibility. The spatial heterogeneity of most soil properties,including soil erodibility,is low and at a relatively small scale. The degrees of autocorrelation of the spatial distribution of soil properties are middle to high.