Effects Of Different Tillage Methods On Soil Organic Carbon Content And Wheat Yield In Rainfed Farming

At present,climate warming due to elevated greenhouse gases has become one of the focused issues in the world.Different agricultural management measures can directly or indirectly affect the soil's carbon sequestration and greenhouse gas emissions,while the change of soil carbon sink is directly reflected in the change of soil organic carbon content.Wheat is the main crop in north China.The research on different tillage management measures affecting organic carbon content and wheat yield have positive meaning to low carbon and high yield farmland in northern area.This study set straw counters-field rotary tillage(SRT)and straw mulching no-till(SNT)two processing at Shanxi Linfen conservation tillage positioning experimental area during 2013-2015,to study the dynamic change of wheat straw decay rate and nutrient release rate in the two kinds of different farming respectively.Then,we calibrate and verify the CENTURY model and APSIM-Wheat model respectively using the data of soil organic carbon(SOC)content and wheat production in the setting of conventional tillage(CT)and no-tillage(NT)in Shanxi Linfen long-term experiment stations for 1994-2010.Next,we use the calibrated and verified models to simulate and predict soil organic carbon content and Wheat production under the climate change in Linfen,and analyze the influence of different tillage measures on soil organic carbon content and the Wheat yield under the future climate change.The test results are as follows:(1)In wet years,the decomposition rate of wheat straw under SNT treatment was slower than that of SRT.In the second year,the residual rate of straw was higher under no-tillage coverage,and there was still obvious decomposition of the rotary tillage treatment.In dry years,the decay rate of straw is slow,especially the larger sidue of no-tillage.There is a large difference in the degree of decomposition of the no-tillage and rotary tillage treatment after a growing season.After a growing season of decay,cellulose content in the straw decreased,while hemicelluloses and lignin content did not change significantly.The content of cellulose in straw was obviously less than that of rotary tillage,and the content of hemicelluloses and lignin was not significantly changed.The total nitrogen content in straw was obviously less than that of rotary tillage,while the organic carbon content was not changed significantly.(2)Through calibrating and verifying the CENTURY model and APSIM-Wheat model,the CENTURY model can well simulate the dynamic change of soil organic carbon content and wheat yield,APSIM-Wheat model can better simulate the dynamic changes of the wheat yield.Through the verification and verification of the model,it can be concluded that the simulated value of the model is in good agreement with the measured value,and the simulation value can better represent the trend of the measured value.The future simulation of soil organic carbon and wheat yield can be carried out by the verified CENTURY model,and the future simulation of Wheat yield can be carried out by the verified APSIM-Wheat model.(3)The no-tillage pattern can increase the content of soil organic carbon whether it's climate change or not.In the next two climate models,the soil organic carbon content of both tillage measures is on the rise,indicating that the implementation of conservation tillage can lead to the overall carbon sink trend of soil carbon.In the future climate change,the carbon sink will be reduced.In the long run,the implementation of no-tillage mode will benefit the solid carbon emission reduction in Linfen.The no-tillage pattern generally increases the wheat yield,especially increase of drought year.Wheat production will increase in the future whether it's climate change or not.In the future,the no-tillage model is more conducive to the high quality and high yield of wheat in Linfen.