Assessment On Environmental Impact Caused By Fertilization Cycle Of Wheat And Maize In Shanxi Province

Fertilizer plays an essential role in today’s agricultural production.The reasonable use of it can improve the grain yield per unit area,while the excessive use will lead to low utilization rate of fertilizer and even cause soil environmental pollution.Against the background of limited arable land and the continuous soil degradation together with the increasing population,applying fertilizer in a scientific and rational way is of great significance to ensure the security of grain production and supply.Making clear the resource consumption and environmental burden associated with fertilization in the grain production process can provide scientific basis for improving grain yield and reducing environmental pollution.At present,it’s urgent to figure out how to comprehensively evaluate the impact on resource and environment caused by fertilization in the grain production process.In this paper,we take wheat and maize,the main grain crops in Shanxi Province,as the research objects.Based on field investigation,the DNDC model is used to simulate the emission of pollutants in the crop production process.In addition,the Life Cycle Assessment(LCA)method is used to establish the inventory of resource consumption and environmental emission concerning the fertilization cycle of wheat and maize in different regions of Shanxi Province.The potential and leading factors of resource and environmental impact with regard to wheat and maize production in different regions of Shanxi Province are discussed.The results are as follows:1.The resource and environmental impact indices of maize fertilization in different regions are as follows:0.3396,the highest index,in Jinnan,0.3274 in Jinzhong and 0.2710,the lowest index,in Jinbei;the variation range for different peasant households is 34.7%～50.4%.The resource and environmental impact indices of wheat fertilization in different regions are as follows:0.2594,the lowest index,in Jinzhong,0.3110 in Liiliang,0.3114 in Changzhi,0.3495 in Linfen,0.3863 in Jincheng and 0.3881,the highest index,in Yuncheng;the variation range for different peasant households is 50.2%～79.3%.The environmental impact caused in the fertilizer application stage is greater than that caused in the fertilizer production stage.2.Several types of impact on resource and environment associated with maize fertilization in Shanxi Province are listed according to the corresponding impact indices from the highest to the lowest:eutrophication(0.5331),acidification(0.4791),land use(0.2155),greenhouse effect(0.1016)and resource consumption(0.0538);while in terms of wheat fertilization,the top four influential types are eutrophication(0.5142),acidification(0.4568),land use(0.3327),global warming(0.1100)and resource consumption(0.0422).As eutrophication and acidification are caused by ammonia volatilization,provided that the fertilization method of broadcast application is replaced with hole application,the ammonia volatilization will be reduced effectively,the comprehensive indices of environmental impact concerning wheat and maize fertilization will be reduced by 23.31%～36.41%and 11.24%～19.02%respectively.3.Comparing the six cities where both maize and wheat are planted,the comprehensive indices of environmental impact of maize planting in Jinzhong,Yuncheng and Luliang are higher than those of the wheat planting in the same regions.While the comprehensive indices of environmental impact of wheat planting in Linfen,Changzhi and Jincheng are higher than those of the maize planting in the same regions.However,the eutrophication indices of maize in Linfen,Changzhi and Jincheng are higher than those of wheat in the same regions.As for environmental acidification index,the index related to maize is higher than that related to wheat in Jincheng,while the other two cities enjoy equal indices concerning the two crops.As eutrophication and acidification are the main types of environmental pollution,the resource and environmental cost of fertilization in maize cultivation system in Shanxi Province is higher than that in the wheat cultivation system.