The Economic And Environmental Benefits Of Biochar And Straw Returning In Dryland Winter Wheat

A large number of straw resources will be produced in agricultural production in China every year,and how to make rational use of these straw is an urgent problem to be solved.It is an effective way to reuse straw by returning straw to the field or making it into biochar into farmland.Through the comparative analysis of farmland with straw and biochar for a long time,this study compares the economic and environmental benefits between the two,and provides the basis for the pursuit of economic and environmental benefits in agricultural production.This experiment designed three treatments,namely: control(CK),fertilization +straw returning(SR)treatment,fertilization + biochar(BC)treatment,study the long-term application of biochar and straw to the economic benefits of winter wheat field in dryland and The main findings of the environmental benefits are as follows:(1)In terms of soil moisture,both biochar and straw returning can maintain soil moisture,and the effect of straw returning is better than that of biochar application.The effect of straw returning on water use efficiency is not obvious,but the application of biochar can significantly improve the efficiency of annual water use in level water.In terms of soil nutrients,biochar and straw returning could increase the contents of total organic carbon,total nitrogen,soil nitrate nitrogen and soil C/N,and the effect of biochar application was better than that of straw returning.As for wheat yield,biochar and straw returning treatment increased 8.6% and 12.2% annually in four years,and the effect of straw returning treatment was better than that of biochar treatment.(2)Economic benefits: the average annual net income of the three treatments is SR(8271 yuan)> BC(7180 yuan)> CK(7008 yuan).Moreover,the annual net income of straw returning is remarkable,and the application of biochar needs the fourth year to have better economic benefits because of the cost input of biochar in the earlier period.(3)Environmental benefits: The order of global warming potential(GWP)of the three treatments was SR > CK > BC through the study of environmental benefits from 2016 to2018.Among them,the annual average decrease of biochar application was 25.1% and the annual increase of straw returning was 13.9% compared with the control group,and the minimum GHGI application of biochar in the two years of greenhouse gas determination was 31.6% lower than that of the control group.There was no significant difference between straw returning treatment and control group(P > 0.05).Therefore,the application of biochar will reduce GWP,and have less impact on global warming,GHGI is smaller,which can effectively reduce the impact of wheat on climate per unit yield;on the contrary,the application of straw will increase GWP,which has a greater impact on global warming,GHGI is not significantly different from the control group.The total carbon footprint of wheat treated with different treatments was SR(1478.11)>CK(1445.83)>BC(1431.03).It can be seen that the application of biochar can reduce the total carbon emissions,on the contrary,the application of straw can increase the total carbon emissions.Carbon footprint per unit yield of wheat under different treatments showed that there were significant differences between biochar and straw returning to field and control group(P < 0.05).Carbon footprint per unit yield of wheat under biochar and straw returning decreased by 10.0% and 11.3% compared with control group.The results showed that the carbon emission of wheat per unit yield produced by applying biochar and straw was less.For the carbon balance analysis of winter wheat farmland system,the carbon sink input of the treatment with biochar and straw was larger than that of the control group,and the effect of straw returning was better than that of biochar application treatment.In short,in terms of economic benefits,both biochar and straw returning can increase yield.The annual economic benefits of straw returning are remarkable.It takes 4 years for biochar application to achieve better economic benefits.In terms of environmental benefits,the environmental benefits of biochar application are better than that of straw returning.Therefore,in order to achieve a win-win situation of economic and environmental benefits,the best way of returning field is to use biochar in four or more years as a cycle,which has better environmental and economic benefits.