新疆伊犁河谷新垦绿洲土壤盐渍化空间特征分析

Spatial Variation of Soil Salinization in the Epipedon at a Newly Reclamation Area in Yili Valley,Xinjiang

在新疆西部伊犁河谷察布查尔县农业示范区采集表层土壤84个,进行了土壤盐分、有机质、pH值和电导率等指标进行实验和统计学分析,探索新垦绿洲表层土壤盐分的空间变化规律及其成因。结果表明:示范区土壤盐渍化明显,主要为硫酸盐和氯化物硫酸盐盐渍化。盐渍化程度主要为轻度、中度盐渍化。示范区西部,盐渍化程度呈现由东南向西北逐渐增大的趋势。东部受洪积扇微地形起伏变化的影响,盐土呈现点片相间分布的格局。中部在垄状隆起区域盐渍化程度较重,两边洼陷部分盐渍化程度较轻。示范区土壤盐渍化过程受地下水、原始地形起伏、原生盐分和人工灌溉等结构性因素和随机性因素的影响。平整土地、灌排结合、林草间作是防治土壤次生盐渍化的主要措施。

In order to explore the cause and spatial transformation of surface soil salinity in a newly reclamation oasis,soil salinity,organic matter,pH and conductivity of 84 typical samples in Yili valley,Xinjiang were tested and statistically analysed.The results showed that salinization and secondary salinization were caused by the interaction of several factors such as parent material,climate,microtopgraphy,hydrogeology and biology.Parent material was the weathering products of igneous rocks in the upstream of Yili river and loess or loess deposits at piedmont of Wusun Mountain.The salt in parent material was the primary source at experimental area.The soil was mainly continuously accumulating salt type in experimental area;groundwater level was above the critical depth.It was in a state of continually accumulation.The soil had a dual nature that salinization and alkalization were carried out simultaneously.The groundwater of experimental area was stored in the space which was formed in the alluvium of Holocene series.So both river water recharge and groundwater recharge participated in the process of modern salification in the experimental area.Soil salinization was remarkable.Sulfate and sulphoxylate were the main types of salinization.It expressed mild and moderate salinization in the soil of experimental area.Salinization degree displayed an increased trend from southeast to northwest in the west of experimental area.Saline soil was alternating distribution which was affected by the change of terrain in the central of experimental area.Salinization degree was severe in the area of ridge terrain and mild at the low-lying district.The process of salinization was commonly affected by structural factors and random factors such as groundwater,terrain,artificial irrigation and primary salinity.Main measures to prevent and control secondary salinization were land leveling,automatic sprinkling irrigation,combination of drainage and irrigation and forest-grass rotation.This paper is a preliminary analysis of spatial differentiation of topsoil secondary salinization in a newly-cultivated soil at arid area.It can help us to understand the mechanisms of secondary salinization under the impacts of both natural and human factors,and also provide comprehensive basic data to prevent and control the process of topsoil secondary salinization.