Study On Carbon Budget And Carbon Footprint Of Regional Planting Industry

As a part of terrestrial ecosystem,planting system is both a carbon sink and a carbon source.Based on the data of planting production in Deyang City and 6 counties(Jingyang District,Guanghan City,Luojiang County,Shifang City,Mianzhu City,Zhongjiang County)in the last 25 years,using methods such as crop parameter estimation,inventory estimation of carbon emissions and comparative analysis of regional systems,etc.The city is divided into plain area of Chengdu(Jingyang District,Guanghan City,Luojiang County),mountain and plain ecotone(Shifang City,Mianzhu City)and hilly area of central Sichuan(Zhongjiang County).The regional differences were compared in order to provide the theory for the development of low carbonization of planting industry in the city.Through this study,the following conclusions are reached:(1)In the last 25 years,the index of multiple cropping in Deyang City was on the rise.Crop planting was mainly grain crops(79.75%),and economic crops were supplemented(20.25%).The proportion of grain crops kept around 80:20.The main food crops were rice and wheat,and the cash crops were rape and peanut.The yield of rice,beans,rapeseed and peanut had increased,but the wheat,corn and bean had decreased.The input intensity of all kinds of agricultural materials in planting industry showed an upward trend that the increase of the intensity of agricultural film input was the largest(about 13 times).Nitrogen fertilizer was the main fertilizer input(56.61%).The regional differences in multiple cropping index,crop composition,yield per crop and input of agricultural materials were obvious in this city.The proportion of grain crops in the hilly region of central Sichuan as well as the mountain and plain ecotone had increased,while the proportion of cash crops in Chengdu Plain had increased.The intensity of chemical fertilizer input was the highest in the hilly area of central Sichuan(average 0.86 t/hm~2),the intensity of total mechanical power input in Chengdu Plain was the highest(average 7.43 kwh/hm~2),and the highest effective irrigation area was in the mountain plain interlaced zone.(0.92 hm~2/hm~2).(2)In the last 25 years,the amount of carbon budget,net carbon sink and carbon footprint of planting industry in Deyang City had the following characteristics:(1)The carbon absorption and intensity of planting industry in the whole city were 191.60*10~4t and 9.69 t/hm~2 respectively.The carbon emissions and intensity(average annual value were 42.69*10~4t and 2.25t/hm~2)showed an upward trend.The carbon absorption was obviously greater than carbon emissions,there was a clear carbon sink(annual average value of 148.91*10~4t)and the trend was fluctuating.(2)The carbon absorption of crops in the city was mainly based on grain crops.The proportion of rice and wheat was outstanding(respectively,45.25%and 24.93%),and the proportion of rape and peanut in the cash crops was also larger(11.71%and 1.25%respectively).Carbon emissions had the largest proportion of carbon emissions which caused by chemical fertilizers(39.81%of the total carbon emissions in the city).(3)The carbon footprint of the planting industry in this city was less than that of each year.There was a significant carbon ecological surplus(annual average value was 15.48*10~4hm~2),but the carbon ecological surplus was decreasing year by year(decrease 21.67%).(4)There were obvious regional differences in amount and intensity of carbon budget,net carbon sink and carbon footprint of planting industry in this city.The carbon budget and net carbon sequestration in the hilly region of central Sichuan were the largest and all showed an increasing trend.When the carbon budget and net carbon sink in the average ecotone of mountainous region were the smallest,the carbon absorption and net carbon sink were decreasing,but the carbon emissions were increasing.The carbon budget and net carbon sequestration in Chengdu Plain were in the middle,the carbon absorption and net carbon sink were decreasing while the carbon emissions were increasing.The main problems in the development of low-carbon planting in this city include:the interannual change of crop carbon sequestration,the increasing of carbon emission and intensity of planting industry,the decreasing trend of ecological surplus,the obvious regional difference of carbon revenue and expenditure in planting industry,citizens have insufficient understanding of the development of low-carbon farming.In the future,we can strengthen agricultural infrastructure,adjust crop structure,stabilize and increase carbon absorption in planting,improve farming practices,develop low-carbon planting in order to reduce carbon emissions from agricultural inputs,increase publicity for low-carbon and circular planting.,train new farmers and other measures.