Comparison On Environmental Impacts Of Existing Grassland Agriculture And Cropland Agriculture Systems In Longdong Area

The"No.1 Central Document"has been proposing to improve the agricultural ecological environment and strengthen the management of agricultural non-point source pollution for eight years?2012²019?.Longdong Area is located in the farming-pastoral zone of northern China,forming a pattern of coexistence of grassland agricultural system and cropland agricultural system.The environmental impacts of the two agricultural systems in Longdong Area have important implications for the agricultural production of the farming-pastoral zone and even the whole country However,there are many economic analysis for grassland agricultural system and cropland agricultural system,but the environmental impacts of the two systems'whole production process are unresolved scientific problems.134 households in Longdong Area were investigated.In view of the whole industry chain of planting and breeding,from the production of agricultural products to the slaughter of livestock,by life cycle assessment method and eFootprint online evaluation software,the environmental impacts of the beef and pork were analyzed.And then,the differences of environmental impacts were summarizd between the two agricultural systems based on the output efficiency of 1 hectare?ha?.And corresponding policy recommendations were presented.The main conclusions are as follows:?1?The comprehensive impact of the 1kg beef output on the existing grassland agricultural system is 2.69E-11 in Longdong Area.Water use?WU?,primary energy demand?PED?,environmental acidification potential?AP?,eutrophication potential?EP?and global warming potential?GWP?are 1.38E+02kg,9.54E+01MJ,9.00E-02 kg SO₂ eq,1.57E-01 kg PO₄^3-eq,1.18E+02 kg CO₂ eq,respectively.?2?The comprehensive impact of the 1kg pork output of the cropland agricultural system on the environment is 1.18E-11 in Longdong Area.Water use?WU?,primary energy demand?PED?,environmental acidification potential?AP?,eutrophication potential?EP?and global warming potential?GWP?are 8.39E+01kg,3.55E+01MJ,3.94E-02 kg SO₂ eq,1.57E-01 kg PO₄^3-eq,2.36E+01 kg CO₂ eq,respectively.?3?In Longdong Area,based on the system output of 1ha,the existing grassland agricultural system produces beef 499.50 kg/ha,the comprehensive impact value is1.34E-08,while cropland agricultural system produces pork 931.50 kg/ha,the comprehensive impact is 1.10E-08.In terms of primary energy demand?PED?and acidification potential?AP?,the existing grassland agricultural system is 38.66%and22.01%higher than the cropland agricultural system respectively;in terms of global warming potential?GWP?,eutrophication potential?EP?and water use?WU?,the existing grassland agricultural system is 25.00%,68.37%and 11.88%lower than the cropland agricultural system respectively.The impacts of water use?WU?,primary energy demand?PED?and environmental acidification potential?AP?of the two systems are mainly from the stage of corn and wheat productions,the breeding stage is the main impact of global warming potential?GWP?and eutrophication potential?EP?.Based on the results above,this study proposes the following suggestions:First of all,change the feed formula of the existing grassland agricultural system in Longdong Area,reducing the ratio of corn and wheat.Secondly,using anaerobic fermentation technology to treat cattle and pig manure in technical application.In terms of policy,expanding the scale of alfalfa cultivation in Longdong Area.