Environmental Impact Assessment Of Corn Growth Process Under Different Water Conditions

At present,the impact of agricultural planting on the environment in Shanxi Province is gradually increasing.As the country's largest crop,the impact on corn is particularly important.In the process of crop growth,water consumption is essential.In order to study the effects of resource consumption and environmental emissions and improvement measures during the whole process of corn planting under different water conditions.Using the meteorological data from 2002 to 2016 in Taigu County,Shanxi Province,the fertilization and irrigation data of corn planting process,soil data and corn growth and development data,using localized corrected DNDC model and numerical simulation method,the whole corn was simulated.CO2,NH3 and N2 O emissions and nitrate leaching under the change of rainfall and fertilizer application,and the spatial distribution relationship of various pollution discharges and yields were established by GIS software.The whole growth of maize was evaluated by life cycle assessment method.The quantitative impact of the process on resource consumption and environmental emissions,analysis and comparison of the relationship between rainfall and resource consumption and environmental emissions,and propose improvements under different rainfall years.The results show:(1)The simulation results of DNDC model show that there is a correlation between precipitation and corn grain yield.The increase of precipitation will increase the yield of crops.At the same time,when the rainfall is in the range of 300mm-600 mm,the yield of winter wheat will increase with the precipitation.And CO2 emissions are increasing trend,the nitrate leaching NH3 volatilization is a downward trend,and the N2 O emissions are decreasing;(2)The spatial distribution indicates that during the corn planting process in Taigu County,the environmental impact of Rencun Township was higher than that of other areas in Taigu County during 2002-2016,and the environmental discharge gradually decreased from the high fertilization area to the surrounding area.trend.(3)Through the life cycle assessment of corn growth process,the potential value of environmental impact is: land use,eutrophication,environmental acidification,energy consumption and greenhouse gas emissions,the main reason for the impact on the environment during planting It is an excessive investment in fertilization in the years when precipitation is low.(4)There is a correlation between the environmental impact of corn during planting and the amount of precipitation.In the environmental factors of life cycle assessment,precipitation has a linear negative correlation with environmental impact.The comprehensive impact factor of the whole process of corn planting under the rainfall of more than 560 mm(bundant water year)is 0.19-0.20,and the annual precipitation is between 350mm-560mm(flat water year).The comprehensive impact factor is 0.17-0.27,annual precipitation.The comprehensive impact factor below 350mm(dry year)is above 0.3,and the environmental impact of the whole process of corn planting is as follows: dry year > flat water year > abundant water year;(5)Numerical simulations show that when the rainfall range is below 350 mm,under the condition of constant fertilization amount,increasing irrigation can increase production and reduce emissions,and the environmental impact factor drops below 0.2;under the condition of no irrigation,it should be reduced to the original fertilization.When the amount of water is 20%-30%,the environmental impact factor is reduced to 0.2-0.3;when the annual fertilization amount is reduced to 80%-85% of the original fertilization amount,the yield is not significantly decreased,but the environmental impact is significantly reduced.Greenhouse effects,eutrophication,energy consumption and land use are related to the type of precipitation.Therefore,in different precipitation years,providing reasonable water supply to corn planting,and rational application of fertilizer,and effectively improving the utilization efficiency of water and fertilizer resources,can effectively control the impact of ecological environment and ensure food production safety.