The Yarkant River Basin Soil And Water Environment Evolution Factors And Prevention Strategies

Yarkant River Basin is in an arid region and it is the largest irrigated area of Xinjiang, which gets attention extensively from all circles because of deteriorating soil and water environment in it.The development of water and soil for a long time leads to the falling of oasis ecosystem vitality, the expansion of artificial oasisand and the atrophy of natural oasis.This years,there are more emphasis on development while ignoring environmental protection of water and soil;more development on artificial oasis while ignoring protection of natural oasis,more protection on irrigation,while ignoring the water and salt balance.Therefore, it is very important for the region to study the water and soil environment change and its influencing factors, then put forward policies of environmental remediation about it.This paper mainly analyzes the water and soil environmental change of Yarkant River Basin over the past 25 years from natural factors and human activities, studies the groundwater level, water quality and soil salinization variation in time and space, and proposes measures for prevention of deterioration of water and soil environment.Land-use change mainly associates with changes in pollution sources which is one of the root causes of the deterioration of water and soil environment. On that basis, this paper analyzes the land-use change in space and time of Yarkand River Basin.In space,the cultivated land in Yarkand River Basin mainly distributes in the middle and lower reaches of Yarkand River with an area of 485360.4hm2,the fruit-bearing forest mainly distributes in the south and near the river regions with an area 485360.4hm2, and the unused land up to 4434022.3hm2.Driven by natural factors and the socio-economic factors, the cultivated land in Yarkand River Basin is the fastest increasing land type from 1990 to 2014,which increases the area of 232750hm2. There are plenty of meadows and woodland turn into farmland and building land with a growing trend.This paper systematically analyzes the temporal-spatial change discipline of the groundwater level, groundwater quality,and soil salinity in the study area.In terms of time,the groundwater level showes a continued downward trend; in space,the level showed the following characteristics:lower in southern area while higher in northern area, and higher near the river while lower far from the river.Groundwater quality at the time showes a deterioration trend, groundwater salinity and ionic concentration also increase significantly over time; in space,from south to north, from the region of near river to desert area, water quality is worse.Besides,the groundwater salinity, the main ion content, Inorganic toxicology indicator and Trace organic indicators show a gradually increasing trend from upstream to downstream,and far less than the area near the river.what's more,the soil salinization is more worse in downstream than the upstream.It is analyzes the influencing factors of water and soil environmental change from natural factors and human activities.The water and soil environmental changes in time mainly due to changes in land-use; and the changes in space are caused by natural factors and human activities, in which the water table and salinization of major conventional ion spatial variations are main factors in natural,the spatial variations of Inorganic toxicology indicator and Trace organic indicators are main factors in human activities. Based on the analysis of the factors affecting water and soil environmental change,there has formulated measures on the prevention and control of soil and water environment deterioration.