Study On Factors Affecting Water Footprint Of Grain Production In Irrigation District

Climate change is becoming a global recognized environmental problem,and agriculture is the basic of the national industry,so study the effects of climate change on grain production is the hot topic of academic circles.The effects of other factors on grain production are not negligible.Water footprint provides a new method to assess the water use efficiency of grain.This study is on the typical irrigation district in semi-humid region — People's Victory Canal Irrigation District and pure-well irrigation area—Cheng'an county and well-canal irrigation area— Huojia county as examples.Study the factors affecting on water footprint per unit yield of grain production comprehensively through two levels of irrigation district and peasant household.The study contents and conclusions are as follows:(1)At first,taking the People's Victory Canal Irrigation District as a study area,this paper calculated the blue and green water footprint per unit yield of winter wheat based on the long series data between 1961 and 2013 using Penman formula and CROPWAT software.Variation of blue and green water footprint and their impacting factors were analyzed.This paper also analyzed the relationship between water footprint and climatic and agricultural input factors using the method of Structural Equation Model.Blue and green water footprint of winter wheat shows a significant downward trend while ETc of winter wheat shows no significant change but yield of winter wheat significant increased between 1961 and 2013.Yield is the key factor affecting the blue and green water footprint of winter wheat.Main meteorological factors affecting the ETc of winter wheat is average wind speed,average temperature,relative humidity,and sunshine hours.Without considering the influence of agricultural inputs,average wind speed is the biggest climate factor affecting blue and green water footprint of winter wheat.Impact of sunshine hours and effective precipitation on blue and green water footprint of winter wheat are smaller than average wind speed.Under the combined effect of agricultural inputs and meteorological factors,main factors affecting blue and green water footprint of winter wheat are scalar quantity of agricultural fertilizers,total power of agricultural machinery,and effective precipitation.(2)Taking Cheng'an county and Huojia county as study areas,by using penmen formula and crop water requirement from the microscopic to calculate the grain production crop water requirement under the different levels of irrigation,and further to account the footprint per unit yield of grain production in different levels of spending and natural conditions have different social and economic characteristics of the peasant households.On this basis,by using the multiple regression analysis method to quantitatively separate the climate factors and other factors affecting the water footprint of peasant household.Definite the key factors affecting the water footprint of grain production of peasant household.The following conclusions: From the peasant household level,irrigation guarantee rate and family characteristics are the key factors that affect water footprint of grain production of the peasant household.The water shortage degree of the peasant household(effective precipitation /crop water requirement during the crop growth)affect the grain yield and water footprint through the irrigation guarantee degree.Under the condition of constant other conditions,the shortage of the water will reduce the irrigation guarantee rate,and the blue and green water footprint will be less.The change degree of summer corn is smaller than winter wheat.(3)In the end,this study definite the incidence of climate factors affecting on the water footprint per unit yield according two levels of the irrigation area and peasant household.Analysis of the change of the light and temperature potential productivity in the irrigation district,definite the effects of climate change on crops yield,combined with the analysis of the effects of climate change on crop water requirement,and then predict the change of the water footprint which is caused by the climate change.Come to a conclusion: In the condition of keeping the existing agricultural input levels and irrigation degree,climate factors comprehensively affect that blue and green water footprint will be under a slight decline trend,the change degree of blue water footprint is smaller than the green water footprint.