Study On Carbon Footprint And Driving Factors Of Farmers’ Corn Production In Gansu And Ningxia

Agricultural production activities are an important source of greenhouse gas emissions,and an important link to achieve carbon peaking and carbon neutrality.The ecological environment in northwest China is fragile,and it is a very important research direction to clarify how agricultural production in this region can actively align with the dual carbon target and achieve low carbon production of major crops.In this study,we take eight northern cities in Gansu and Ningxia provinces(autonomous regions)as the study area,and adopt the Life Cycle Assessment method to reveal the current carbon emission status of farmers’ corn production.Further,machine learning algorithms of random forest were used to explore the main factors affecting the carbon emission intensity per unit of corn product from both natural and human aspects.The main results are as follows:(1)The average carbon footprint of each ton of corn produced by farmers in the study area was 670.48 kg CO2-eq,and the carbon emissions of farmers in Gansu Province(723.26 kg CO2-eq)were higher than those in Ningxia Hui Autonomous Region(513.34 kg CO2-eq).The carbon footprints of each region in descending order are Lanzhou City > Baiyin City > Qingyang City > Pingliang City > Guyuan City > Zhongwei City > Dingxi City > Wuzhong City.(2)In terms of the composition of carbon footprint sources,the carbon footprint of the whole life cycle of corn production in the study area mainly originated from the raw material production stage(52.15%),the field planting stage(46.52%),the harvesting stage(1.18%),and the straw disposal stage(0.15%).In terms of the contribution of inventory substances,the input substances that contribute ≧ 1%to carbon emissions are: compound fertilizer(34.26%),nitrogen fertilizer(31.08%),irrigation water and electricity(11.89%),machinery fuel(7.97%),agricultural film(6.85%)and phosphate fertilizer(6.21%).Fertilizer occupies a larger share of emissions in all regions,while irrigation also occupies a larger share in areas with irrigation access.(3)The factors affecting the carbon emission intensity of the same corn output in order of importance are: monthly average precipitation during the corn growing period,slope of farmland,planting scale,disaster,and monthly average temperature during the corn growing period.Thus,for the semi-arid region of northwest China,the main factors affecting carbon emissions from corn production are natural ones,especially precipitation is the main cause of carbon emission intensity of corn production.In general,human factors are not major factors and play a secondary role in carbon emissions.(4)Overall,monthly average precipitation and slope of farmland during the growing period of corn are negatively correlated with carbon emissions,and planting scale is positively correlated with carbon emissions.Among them,the carbon footprint is higher in areas with low precipitation,indicating that growing corn in this area has a high environmental cost.Based on these findings,the paper proposes the following production optimization recommendations:(1)Strengthen technical training.Farmers in the study area have a low level of education and do not understand the use of fertilizers,and unscientific farming practices such as over-fertilization are more obvious.Therefore,it is suggested that the relevant government departments should,on the one hand,make more efforts to carry out agricultural training to compensate for the lack of farmers’ knowledge and technology,improve their cultivation techniques,and thus circumvent the unscientific cultivation behavior of farmers.On the other hand,they need to provide public services such as soil testing and formulations to guide the fertilization program in areas with different soil conditions.(2)Optimize corn planting areas.According to the relationship between natural conditions and carbon emission intensity,scientific planning of corn planting areas,areas with low average monthly precipitation during the growing season are not suitable for corn planting,and other crops that are relatively more drought tolerant should be selected.Areas with steep slopes are also unsuitable for corn planting due to severe soil erosion,and should be returned to forestry and grass or planted with crops that maintain soil and water.(3)Valuing the environmental value of smallholder corn production.For farmers in the semi-arid northwest,their smallholder corn production instead has certain environmental advantages,and the importance of smallholder corn production should be increased when planning the planting scale,and it is not advisable to blindly expand the scale of corn planting for farmers.