Carbon Footprint Of Alfalfa Production In Gansu Province

Alfalfa（Medicago Sativa Linn）is a high-quality forage crop that is the basis of herbivorous animal husbandry.Studying alfalfa’s carbon emissions is of great significance for reducing agricultural carbon emissions and is also the basis of studying the life cycle carbon footprint of herbivorous animal products.Gansu Province is one of the main alfalfa producing areas in China,and its planting area ranks first in the country.Alfalfa is a high-quality forage crop,which is the basis of herbivorous animal husbandry,so its carbon emissions are also the basis for studying the life cycle carbon footprint of herbivorous livestock products.In this paper,the carbon footprint of alfalfa production in Gansu Province was taken as the research object.Through actual research,farmers and enterprises have been invested in alfalfa production.Weighted average is used to obtain the average production input.The life cycle assessment method and online modeling method are used to clarify alfalfa carbon emissions The main links are compared,and the differences in carbon emissions between the rain-fed agricultural areas on the Loess Plateau and the oasis agricultural areas in the Hexi Corridor,and the different production entities（farmers and enterprises）,as well as the influencing factors,are finally put forward.The main conclusions are as follows:（1）The total greenhouse gas emissions of 1 t of alfalfa grass produced by farmers in rain-fed farming areas are 216 kg CO₂-eq.The planting process,harvesting process and transportation process are 215 kg CO₂-eq、0.108 kg CO₂-eq、0.39 kg CO₂-eq,respectively.The total greenhouse gas emissions from the production of 1 t of alfalfa fresh grass by farmers in the oasis agricultural area of the Hexi Corridor is 226kg CO₂-eq.The planting process,harvesting process and transportation process are212 kg CO₂-eq,12.1 kg CO₂-eq,1.63 kg CO₂-eq,respectively.The total greenhouse gas emissions from the production of 1 t of alfalfa grass by rain-fed agricultural enterprises are 314 kg CO₂-eq.The planting process,harvesting process and transportation process are 298 kg CO₂-eq,15.7 kg CO₂-eq,0.899 kg CO₂-eq,respectively.The total greenhouse gas emissions from the production of 1 t of alfalfa grass in the oasis agricultural area of the Hexi Corridor is 578 kg CO₂-eq.The planting process,harvesting process and transportation process are 559 kg CO₂-eq,17.7 kg CO₂-eq,1.97 kg CO₂-eq.（2）Comparison the carbon emissions in different geographical areas,greenhouse gas emissions of 1 t fresh alfalfa grass produced by farmers in rain-fed agricultural areas were 216 kg CO₂-eq,and those of farmers in oasis agricultural areas were 226 kg CO₂-eq.Greenhouse gas emissions from rain-fed agricultural areas in the planting stage are 0.02 times more than those in oasis agricultural areas,and greenhouse-gas emissions in the oasis agricultural areas during harvest and transportation are 111 times and 3.18 times higher than those in rain-fed agricultural areas,respectively.The greenhouse gas emissions from the production of 1 t fresh alfalfa grass by enterprises in rain-fed agricultural areas were 314 kg CO₂-eq,and those from enterprises in oasis agricultural areas were 578 kg CO₂-eq.The greenhouse gas emissions of enterprises in oasis agricultural areas during the planting,harvesting and transportation stages were 0.88 times,0.13 times,and 1.19 times higher than those in rain-fed agricultural areas,respectively.（3）Comparing the carbon emissions of different producers,the greenhouse gas emissions of 1 t fresh alfalfa grass produced by farmers in rain-fed agricultural areas were 216 kg CO₂-eq,and the emissions of enterprises were 314 kg CO₂-eq.The greenhouse gas emissions of enterprises in rain-fed agricultural areas during the planting,harvesting and transportation stages were 0.38 times,144.4 times,and 1.31times higher than those of farmers.Greenhouse gas emissions from farmers producing1 t fresh alfalfa grass in oasis farming area were 226 kg CO₂-eq and 578 kg CO₂-eq respectively.The greenhouse gas emissions of enterprises in the Hexi Corridor during the planting,harvesting and transportation stages were 1.64 times,0.46 times,and0.21 times higher than those of oasis farmers.In order to reduce the carbon emissions of alfalfa production,based on the above conclusions,this article proposes the following countermeasures:（1）Increase the distribution of alfalfa industry in rain-fed agricultural areas on the Loess Plateau.By comparison,it can be found that alfalfa production of the same quality has smaller carbon emissions in rain-fed agricultural areas.The Hexi Corridor Area mainly adopts the model of high input and high output,and the advantages of alfalfa hay production are obvious;rain conditions in rain-fed agricultural areas are acceptable and have the basis for large-scale alfalfa production,but the current level of attention and input is insufficient.The rain-fed agricultural zone in Gansu is located in the ecotone between agriculture and animal husbandry in China.Under the favorable policies of changing grain to feed,more attention should be paid to alfalfa production.（2）Strengthen support for alfalfa production by farmers.It can be seen from the comparison results that the carbon emissions of alfalfa produced by farmers are significantly smaller than those of enterprises.The main reason is that the enterprise adopts industrialized management,and various inputs are relatively large,while small-scale farmers produce small inputs.However,at the farmer level,there is no substantial subsidy for alfalfa production,and there are many supporting policies for enterprises.In view of the environmental advantages of farmers’production of alfalfa,the grain to feed policy should introduce support measures for farmers to grow alfalfa.（3）Strengthen the management of the use of chemical agricultural materials.Through investigation,it was found that all producers have the habit of excessive use of agricultural chemicals,especially mulch and nitrogen fertilizer.Plastic mulch and nitrogen fertilizer have significant greenhouse gas emissions in the production process,and nitrogen fertilizer emissions in farmland are also large.Soil testing and fertilization are almost not used in the survey area,and fertilization is very random.In the future,the fineness of alfalfa production should be strengthened to minimize the use of agricultural chemicals.