Study On Water Use Of Crops And Water Resource Management In Liuyang City Based On Water Footprint Theory

The application of water footprint theory and methods in water resource management of river basin is a frontier issue that is deeply explored in scientific research today.The green water and blue water in water footprint of crop are quantified by the amount of water required from evapotranspiration.In this study,the calculation method of crop water footprint based on regional water use is introduced.The water footprint of crop is calculated from the perspective of water demand and water consumption,which includes water loss due to evapotranspiration and leakage in the process of water transport,arable land use and drainage.It can also reflect the efficiency of water use,operation level of irrigation system and water use of agricultural production at regional scale,providing reference for water resource management of agricultural.Using the theory and method of water footprint as well as the CROPWAT model,this paper calculates the evapotranspiration and effective precipitation.At the same time,it calculates the water footprint of the major crops based on the data of meteorology,crop coefficients and yield,fertilizer use and soil conditions.Such methods are used to calculate and analyze the water footprint of major crops in Liuyang City in 2010 to 2019.Then,the variation characteristics of the water footprint of the major crops are analyzed based on time and data statistical methods,and suggestions for reducing water footprint are proposed.For the study of the water footprint of agricultural production in a relatively small area,on the one hand,it enriches the research cases of the water footprint,provides a reference for the reference value of the formation area and crops,and on the other hand,helps the region to reduce the water footprint of crop production through comparative purpose.Based on the research of this paper,following conclusions are made:(1)The overall downward trend of the unit water footprint and total water footprint of major crops in Liuyang City are based on the calculation method of water footprint of crop water demand and regional water use.Cotton has the highest water footprint per unit,and the lowest is fruits and vegetables;the highest total water footprint is rice and the lowest is cotton.It is found that the calculation results based on crop water requirement(under the most suitable growth conditions)are lower than that based on regional water consumption by comparing the calculation results of blue water requirement and blue water use of crops:the calculation based on water demand of crop,under the most suitable growth conditions,is lower than the calculation result based on regional water use:from 2010 to 2019,the total water footprint of blue of crops is 1-4 times of the total blue water requirement.The blue water footprint of rape,vegetable and cotton are 28,6 and 0.44 times of blue water requirement,respectively.The blue water footprint of early rice,tobacco and fruit are 3 times,2 times and 3 times,respectively.(2)Using the theory and method of virtual water,this paper calculates virtual water based on the data of crop consumption,crop yield and trade.The annual consumption of virtual water is 840 million m~3 in Liuyang City,among which the consumption of virtual water in rice,vegetables and fruits is decreasing,while the consumption of tobacco and rape is increasing.At the same time,it calculates the average annual flow of virtual water that is 650 million m~3,accounting for 43%of the virtual water,among which the output of rice and vegetables accounts for 48%of the virtual water.After 2013,the average annual input of virtual water of tobacco is180 million m~3,accounting for 29%of the virtual water flow.(3)Based on the results of water footprint calculation and virtual water flow,combined with the analysis of water supply capacity,the improvement path of water resources management of agricultural was proposed in Liuyang City:Take ET management as the direction to reduce water consumption in the process of transportation and distribution,so as to save water in the true sense;connect and manage ponds,channels and farmland to reduce water leakage;precision irrigation and fertilization of farmland through agricultural technology;management measures should be used to unify and coordinate management between basins and the upper,middle and lower reaches of basins,and reward and punishment systems should be established to stimulate internal management power.Virtual water inflow areas should jointly shoulder upstream water resources protection problems,so as to achieve the management goal of synchronous and efficient use of inter-regional water resources and economy.