Appropriate Scale Study Of Cultivated Land In The Tarim River Basin With Water Resource Constraints

The Tarim River basin evaporated,the precipitation is rare,and it is a typical irrigation agriculture area.Unlimited expansion of cultivated land in the basin can lead to agricultural water extruding ecological water,resulting in an ecological environment hazard.Therefore,under the framework of water resource constraints,it is important to conduct an appropriate scale study of cultivated land to promote sustainable development and ecological protection in the Tarim River Basin.This paper estimated the water demand for agricultural irrigation based on the water footprint theory and then constructed a model to calculate the appropriate scale of cultivated land,found out the appropriate scale of cultivated land in the Tarim River basin under two scenarios of priority economic development and priority ecological protection from 2010 to 2019,and analyzed the overload situation of cultivated land.The main findings of the study are as follows.(1)In terms of water availability for agricultural irrigation,under the priority scenario of economic development,the water availability for agricultural irrigation in the Tarim River basin fluctuates and increases from 24.59 billion m~3 in 2010 to 29.54 billion m~3 in 2019,while under the priority scenario of ecological protection,the water availability for agricultural irrigation fluctuates and increases from 17.31 billion m~3 in2010 to 20.74 billion m~3 in 2019.Except for the Aksu Prefecture and Kizilsu Kirghiz autonomous prefecture,the water available for agricultural irrigation in the rest of the Tarim River basin shows a fluctuating upward trend.In terms of water use structure,under the priority scenario of ecological protection,the difference in water use between domestic water use,production water use,and ecological water use in the Tarim River Basin decrease compared with the priority scenario of economic development.(2)In terms of agricultural irrigation water demand,except for the Kashgar Prefecture,the change of agricultural irrigation water demand in all regions shows a linearly decreasing trend during 2010-2019.Among them,the agricultural irrigation water demand in Bayingol Mongolian Autonomous Prefecture is always higher than that in other regions;the agricultural irrigation water demand in the Aksu Prefecture shows a fluctuating decreasing trend;the decreasing trend in Kashgar Prefecture is more obvious than that in other regions;the agricultural irrigation water demand in Kashgar Prefecture increases in fluctuation,but the increase is not large;the agricultural irrigation water demand in Hotan Prefecture reaches the highest value in 2010,and then decreases for three consecutive years,and also shows a fluctuating decreasing trend overall.The trend is also fluctuating.(3)In terms of the appropriate scale of cultivated land,the appropriate scale of cultivated land in the Tarim River basin under the priority scenario of economic development and the priority scenario of ecological and environmental protection are both smaller than the actual scale of arable land,i.e.,the actual scale of cultivated land is in an overload state.Under the priority scenario of economic development,9%-18%of the cultivated land in Bayingol Mongolian Autonomous Prefecture,7%-19% in Aksu Prefecture,3%-15% in Kizilsu Kirghiz Autonomous Prefecture,10%-19% in Kashgar Prefecture,and 6%-19% in Hotan Prefecture need to be retired;under the priority scenario of ecological protection,13%-25% of the actual cultivated land in Bayingol Mongolian Autonomous Prefecture,10%-27% in Aksu Prefecture,and 10% in Kizilsu Kirghiz Autonomous Prefecture need to be retired.In the ecological protection priority scenario,Bayingol Mongolian autonomous prefecture needs to retreat 13%?25%,Aksu Prefecture needs to retreat 10%?27%,Kizilsu Kirghiz Autonomous Prefecture needs to retreat 4%?21%,Kashgar Prefecture needs to retreat 14%?27%,and Hotan Prefecture needs to retreat 8%?28%.(4)The Tarim River Basin should optimize the crop planting structure,gradually reduce the area planted with high water-consuming crops such as cotton,and increase the proportion of low water-consuming and drought-tolerant crops.At the same time,efficient water-saving irrigation measures should be vigorously promoted to effectively reduce the proportion of water used in agriculture in order to promote farmers' income and healthy development of the agricultural economy.In addition,the principle of ecological priority needs to be adhered to in the development of the agricultural economy,and importance should be attached to the improvement and enhancement of the quality of the ecological environment to ensure a virtuous cycle of the ecological environment and maintain the security and stability of the watershed ecosystem.