Study On The Allocation Of Agricultural Planting Structure In The Lower Reaches Of Tarim River Based On The Temporal And Spatial Evolution Of Water Footprint

The shortage of water resources is also one of the key factors restricting China’s agricultural development.With the continuous and rapid development of social economy and the continuous promotion of urbanization,the competition for water resources in various industries and regions is becoming increasingly fierce,and it is increasingly difficult to increase food production by expanding irrigation area.However,the uneven distribution of water resources,floods,climate change and unreasonable water use policies lead to the severe reality of resource,structural and polluting water shortage in China’s agricultural water resources.At present,the demand for water resources for agricultural development is mainly related to climate change,planting area,planting structure and water-saving technology.Through scientific and reasonable adjustment of crop planting structure,we can effectively tap the potential space of agricultural water-saving.In Xinjiang,the lack of water resources and unreasonable consumption of agricultural water are one of the long-term problems faced by agricultural production.In the 1970s,Tarim,an inland region,faced the first shortage of water resources in China’s history.How to ensure the coordinated development of agricultural economy and sustainable utilization of water resources is an urgent development problem in the lower reaches of Tarim River Basin.Taking the lower reaches of Tarim River as the research area,the present situation of agricultural water footprint in this region was quantitatively revealed and the agricultural planting structure was simulated.The research includes three aspects:first,the utilization of water resources in the lower reaches of Tarim River is comprehensively analyzed based on the spatial-temporal evolution of water quantity,precipitation and water quality,so as to master the dynamic changes of water resources in the lower reaches of Tarim River.Second,CROPWAT8.0 model software was used to calculate and analyze the green water footprint,blue water footprint and grey water footprint of winter wheat,spring wheat,corn and cotton and cash crops in Luntai County,Korla City and Yuli County in the lower reaches of Tarim River from 2000 to 2019.Grasp the water resources consumption of main crops in the lower reaches of Tarim River.Thirdly,a multi-objective optimization model was established to simulate the allocation of agricultural planting structure in the lower reaches of Tarim River,aiming at the overall consideration of sustainable utilization of water resources and economic development.The main research results show that:(1)Changes in water resources in the lower reaches of Limu River:in terms of changes in water delivery volume,taking 2010 as the boundary,the water delivery volume generally shows a trend of increasing first and then decreasing;In terms of precipitation,in terms of time series change,the precipitation of three counties and cities in the lower reaches of the Tarim River increases first and then decreases.The overall trend of precipitation change is consistent with that of water conveyance.In terms of spatial variation,before 2010,the precipitation pattern of Luntai County in the upper part of the Tarim River was significantly higher than that of Korla City in the middle part and Yuli County in the lower part;In terms of water environment quality,the water environment quality in the lower reaches of Tarim River has been continuously improved since the ecological water conveyance project.(2)Temporal and spatial changes of process water footprint of winter wheat,spring wheat,corn,cotton and other major crops in three counties and cities in the lower reaches of the Tarim River from 2000 to2019:affected by differences in policies and field management,crop planting area and unit yield fluctuate every year.There are crop type differences and spatial differences in blue water footprint,but they are higher than green water footprint,It is proved that the four crops mainly consume blue water,that is,irrigation water;Under the condition of consistent yield per unit area of crops,affected by the time and space differences of temperature,precipitation and sunshine,the green water footprints of main crops are low,which proves that the effective precipitation of three counties and cities in the downstream area is low;Affected by the change of chemical fertilizer application measures,except wheat,the other three crops showed a trend of increase and decrease.(3)Through the rational allocation of the planting area of main crops in the lower reaches of the Tarim River in the past 20 years:the planting area of Winter Wheat in Luntai County in the lower reaches of the Tarim River can be configured as 9.1×10~3hm~2,spring wheat planting area configurable 3.7×10~4hm~2,corn planting area configurable 1.1×10~4hm~2,cotton configurable 1.8×10~3hm~2;The planting area of Winter Wheat in Korla can be configured as 3.2×10~3hm~2,spring wheat planting area configurable 4.1×10~4hm~2,corn planting area can be configured as 9.0×10~3hm~2,cotton configurable 4.6×10~3hm~2;The planting area of Winter Wheat in Yuli County can be configured as 9.1×10~3hm~2,spring wheat planting area configurable3.7×10~4hm~2,corn planting area configurable 1.12×10~4hm~2,cotton configurable 1.8×10~3hm~2,the overall configuration of the three counties and cities meets the policy requirements of market demand,cultivated land protection,food security and ensuring the development and supply of animal husbandry under the existing socio-economic conditions,and achieves the purpose of reducing water resource consumption and higher economic benefits.