Integration Of Environmental Footprints And Its Impact Analysis Of Beijing Crops Based On Life Cycle Assessment

Greenhouse gas emissions,lack of fresh water resources and shortage of bio-productive land are the three major environmental problems in the world,among the many environmental problems facing the world.The agricultural sector is China's largest water-consuming sector because it is an important source of our national economy in terms of food security,employment and rural livelihoods.However,it is also a major source of land and water use and the environmental burden of greenhouse gases,nutrients and other types of emissions.Therefore,how to scientifically evaluate the resource and environmental coercion of the agricultural sector has become an urgent problem in the environmental field.This paper introduces the concepts related to environmental footprint and takes crops in Beijing as the research object to quantitatively measure different types of environmental footprint to effectively characterize the environmental impact of the agricultural sector.In order to avoid the traditional environmental footprint assessment only from the perspective of resource consumption,it is impossible to assess its potential environmental impact.This paper quantitatively analyzes the water footprint,carbon footprint and carbon footprint of major agricultural crops?winter wheat,corn,soybean,potato,peanut and cotton?in Beijing.The land footprint is based on the life cycle assessment?LCA?method.In addition,in order to exclude a single footprint,only the limitation of environmental impact in a certain aspect can be evaluated,and in order to quantify the mutual influence and restriction effect between different footprints,this paper integrates different environmental footprints through standardization,weight judgment and integration to form A comprehensive footprint indicator that comprehensively considers the environmental impact of crops.The results show that the water footprint of crops in Beijing is cotton,which is 90209L H₂Oe?kg^-1,which is about 2.77 times that of soybean and 9.28 times of peanut times,17.07 times of winter wheat,22.67 times of maize and 21.23 times of potatoes;the carbon footprint per unit area of cotton is the largest,3341.14 kg CO₂-eq/hm²,which is about 5.21 times of winter wheat,10.25 times of corn,4.49times of soybean,9.30 times the potato and 4.34 times the peanut;the maize's maximum average value of land footprint is 6.63×10⁵ gha,which is 3.04 times,27.77 times,30.75 times,166.88 times and188.09 times of winter wheat,peanut,soybean,cotton and potato.In the integrated environmental footprint,the contribution of water footprint and land footprint is relatively large,the carbon footprint is relatively small,indicating that Beijing's environmental pressure on crop water resources and land resources is greater.Cotton has the largest integrated environmental footprint,with an average value of9.714 over 15 years,followed by soybeans,winter wheat,peanuts,maize and potatoes.The integrated environmental footprint of maize and potato is the smallest,with mean values of 3.504 and 2.447,which are only 0.361 and 0.252 for cotton.Except the integrated footprint of peanuts has increased by 60.11%,the overall integrated footprint has shown a downward trend,especially the decline rate of soybean reached 58.25%.The integrated environmental footprint can more fully characterize the environmental impact than any single environmental footprint.The results of this study also indicate that Beijing should consider planting more maize.Maize not only has a small environmental impact,but also a crop with relatively high economic benefits,avoid the cultivation of cotton and other crops that have a greater impact on the environment.In order to further assess the potential impact of the crop's environmental footprint,this paper analyzes the environmental impact of different crops from three aspects:Human health,Ecosystem quality,and Resource based on the Eco-indicator99 life cycle assessment method.In the entire environmental impact assessment,in the end point indicator of Human health,the environmental impact ranks as cotton>potato>soybean>peanut>maize>winter wheat;and in the category of Ecosystem quality is peanut>winter wheat>cotton>potato>maize>soybean;in terms of Resource,the environmental impact is ranked as cotton>soybean>peanut>winter wheat>potato>maize,and cotton is much larger than the other five crops.In the Eco-indicator99 method revised by Pfister et al,for water footprint,the three aspects of cotton have the largest impact,followed by soybean,maize and potato with the smallest environmental impact values.Under the double pressure of scarce resources and environmental stress,in order to balance economic development and environmental quality,environmental impact assessment and regulation of crop production has become an urgent task.According to the research results,in order to reduce the environmental pressure on crop resources in Beijing,it is recommended that select ecological compensation methods for inter-regional trade cooperation for food crops with high environmental impact?cotton,soybean,etc.?.Promoting water-saving irrigation technology and publicizing water-saving concepts to maximize the utilization of water resources.At the same time,it advocates the use of organic and farm fertilizers;the three-dimensional planting model and multi-crop planting are implemented using the relationship between different species compound cultivation to maximize land use.