The Spatio-temporal Evolution Of Water Footprint For Cotton Production In Xinjiang

Xinjiang, the most dry inland agricultural irrigation area in west-China, with weathercharacteristics as follows: high yearly accumulative temperature, few precipitation, highevaporation and dry climate. Rapid population increases as well as fast economic andagricultural development lead to serious crisis to water resources in Xinjiang province.Agricultural water use made up to95%of the total water use in Xinjiang. Xinjiang is themost important cotton granary in China; cotton production plays the most important part inXinjiang’s agricultural production, which consumes huge quantity of water. Therefore wateruse efficiency in cotton production has important relationship with the sustainabledevelopment of agriculture in Xinjiang.Solutions to the shortage of water resources in Xinjiang not only rely on technologymethods, but also need more supports from policy and management. Therefore, In order tothe serve the policy making and water management, we need to grasp the water using statusof the cotton production in Xinjiang. As the water consumption evaluation method in cropproduction process, crop water footprint provides a new train of thought for regionalagricultural water management evaluation.(1) Water footprint of cotton product (WFPC) in Xinjiang show a significantly reducetrend in recent30years, while cotton water footprint (WFC) show an increase trend.Yearly average value of WFPC in1980s is14.29m~3/kg, and decreased to4.9m~3/kg in2000s. The blue water footprint of cotton product (BWFPC) has a similar decreasing trendwith the WFPC, while green water footprint of cotton product (GWFPC) takes less than10%part of the WFPC. Results show that cotton production in recent30years developed rapidly,Cotton production level in Northern-Xinjiang keeps a higher level compared to Southern andEastern Xinjiang. Cotton production level in Southern and Eastern Xinjiang has a lower startpoint, but developed fast, there are still a lot of potential to rise.Yearly average value of WFC in1980s is36.45×108m~3/a, and increased to119.20×108m~3/a in2000s, which means that cotton production consumed119×108m~3water resource,nearly1/8of the total water resource in Xinjiang.(2) Space distribution of WFPC in Xinjiang is increasing from north to south, while thespace distribution of WFC is increases first and then decreases from northwest to southeast.Distribution situation of WFC, BWFC, GWFC in Xinjiang are basically the same.Counties with smaller WFPC concentrated in the tarim river basin, and GuoLe Mongolian autonomous prefecture, middle and lower reaches of Manias river basin and Usu City.Counties with larger WFPC concentrated in Urumqi city, the surrounding of turpan, karamaycity, Yining County and western kashgar. Space differences of WFPC in Xinjiang arediminishing yearly.(3) The direct effect factors of WFPC is cotton yield, the main effect factors of WFPCare chemical fertilizer usage, farm machinery power and wind speed.Statistical analysis of the related factors for WFPC shows that: fertilizer usage, farmmachinery power and temperature have a significant negative correlation with the WFPC, andwind speed has significant positive correlation with the WFPC. The increasing of Fertilizerusage promoted the cotton yield and reduced the WFPC. Farm machinery power increasemeans that cotton production Xinjiang developed toward scale and intensive direction haspositive effects to the control of WFPC. The wind-speed reduced greatly which abate the cropevapo-transpiration, and has positive effects on the WFPC’s reduce. Temperature also is thefavorable factors of the WFPC.(4) Virtual water of cotton (VWC) in xinjiang has been in the output state in recent30years, with tendency of gradually increase.VWC in Xinjiang accounts for about1/8of total water resources in Xinjiang. In which,the proportion of green virtual water of cotton (GVWC) increased, while the proportion ofblue virtual water of cotton showed a trend of decrease. Except the altay region, other indexsare virtual water net outflows area. Three virtual the water out centers located in the bothsides of tianshan mountain foothills, which is the north and west margin of tarim basin andsouthwest junggar basin. The output of the water resources directly caused cutoff of riversdownstream with dry and atrophy of Lake wet-land. There are virtual water inflows in IliRiver and Eltrix river basin which have abundant water resource. Reflect the Water and soilresources are imbalances and water utilization is not reasonable, intensifies environmentalcrisis in downstream of the inland river.(5) Finally, cotton production advises of WFPC were proposed through the analysis ofthe research results.Make rational, full and efficient use of blue water resources; Increasing productioninputs; Promoting agricultural mechanization development; Optimization cotton industrylayout; Committed to cotton production research and forecast; Make the cotton price stabilityand the water price reasonable; Implement inter-basin diversion; adjust the imbalance virtualwater flow in Xinjiang; Implement ecological compensation and ladder type water price.