Carbon Sequestration And Emisson Reduction Of Different Fertilization And Its Exitension Regulation In Paddy Fields In The Middle And Lower Reaches Of Yangtze River

Fertilizer is one of the important input factors in agricultural production.It is a significant link in grain secruity and food safety and other issues,which has an irreplaceable effect on the increase of grain production and farmers’ income.”12th Five-Year Period",China has achieved that the grain output increased continuously for 12 years,while excessive fertilization caused the agricultural environment has also aroused high attention.In order to pursue high yield and fertilize excessively,the negative externalities are becoming more and more obvious.Agricultural products quality decline,soil acidification and groundwater pollution and a series of environmental problems continue to intensify.Small-scale production is primary in China.The number of farmers is large and they are scattered.In the agricultural production,low utilization rate of fertilizer,excessive fertilization etc.has become a common phenomenon.China’s total fertilizer production and total sales accounted for more than 1/3 of the world,the farmers’ behavior and decision directly affects the fertilizer inputs.Therefore,from the perspective of farmers,how to guide the farmers’ scientific and reasonable fertilization is an urgent problem to protect the ecological environment and promote the sustainable development of agriculture.In this study,we choose the middle and lower reaches of the Yangtze River as the study area.In order to determine the net mitigation potentials of the soil under different fertilization measures,a quantitative study from macroscopic regional angle is conducted to analyze the effect of different fertilization measures on paddy soil organic carbon sequestration and greenhouse gases emission in the middle and lower reaches of the Yangtze River by the method of Meta-analysis.Through the questionnaire survey,the fertilization behavior of farmers is qualitatively studied from the microscopic point of view,so as to clarify the influencing factors of farmers’ willingness to reduce fertilization.Based on the combination of regional research from macro angle and farmers behavior from micro angle,this paper clarifies the suitable fertilization methods in the middle and lower reaches of the Yangtze River under the condition of net emission reduction,and puts forward the corresponding policy suggestions accordingly.The main conclusions are as follows:(1)The results showed that all fertilization treatments could significantly increase the relative annual change of SOC content in paddy fields,and the RAC under N,NPK,O and OF were 0.03,0.16,0.22 and 0.31 g-kg-1·a-1,respectively.The highest of the RAC among the four fertilization modes was the OF treatment.With the extension of the cycle,the rate of increase of organic carbon in paddy field decreased gradually under the four fertilization treatments.In the carbon cycle,the ratio of organic carbon in paddy soil increased respectively 5.8%,29.43%,32.71%and 43.05%,among which OF was the highest.Therefore,from the perspective of paddy soil carbon fixation,OF fertilization model is more suitable for the middle and lower reaches of the Yangtze River paddy field.(2)It showed that the effects sizes of N,NPK,O and OF on annual CH4 emissions were 0.24,0.27,0.53 and 0.63,respectively.While the effect size of N,NPK,O and OF on annual N2O emissions were 1.25,1.26,0.11 and 1.41,respectively.At the same time,the trend of greenhouse gas change at different fertilization levels and fertilization time is different,the net warming potential of fertilization was OF>O>NPK>N,and the grain yield is NPK>OF>N>O.From the point of view of higher yields and greenhouse gas emission reduction,NPK is more appropriate than the other two fertilization modes in middle and lower reaches of the Yangtze River.(3)Farmers behavior by the farmers of the individual characteristics,operating characteristics,farmers fertilizer application situation,the farmer’s perception of fertilizer and the influence of government behavior several aspects of influence;The willingness of farmers to reduce fertilization is determined by the determination of the amount of fertilizer applied,the degree of understanding of the quality of fertilizer brands,the negative effects of over-fertilization,the expectation of new fertilizers and the solutions to the problems.Among them,the expectation of new fertilizer varieties was negatively correlated with famers’ willingness to reduce fertilization,farmers to determine the amount of fertilizer based on the understanding of the quality of fertilizer brands,excessive fertilization and the negative impact of the solution to the problem and farmers’ willingness to reduce fertilization is a positive correlation.