Effects Of Tillage And Straw Management Practices On Soil Properties,Greenhouse Gas Emission,and Yield Of Summer Peanut Farmland

High yield,high efficiency,and environmentally friendly production of crops are the basic requirements of agricultural production in China and are also the key to achieving the sustainable development of agriculture.Soil is the foundation of agricultural production and shallow cultivation layer,compact structure,and low low fertilizer utilization efficiency have become important factors limiting the sustainable development of agriculture.In addition,agricultural emission reduction is also an urgent issue for sustainable agricultural development.Therefore,optimizing agricultural management measures to improve soil structure,increase soil fertility,and reduce greenhouse gas emissions is an important way to achieve high yield,high efficiency,and environmentally friendly cooperative development of agriculture.Tillage and straw management are important agricultural production practices;however,there is a lack of systematic research on the effects of different tillage and straw management practices in improving soil productivity,increasing crop yield,and promoting sustainable agricultural development.In this study,the fixed-site field experiment and ¹⁵N tracer micro-plot experiment were performed at the experimental station of Shandong Agricultural University.The present study was carried out using a split-plot design,including three main plots（no-tillage,rotary tillage,and plow tillage）and two subplots（wheat straw returning and without wheat straw returning）.There were six experimental treatments:no-tillage with wheat straw mulching（NTS）,no-tillage without wheat straw mulching（NT）,rotary tillage with wheat straw returning（RTS）,rotary tillage without wheat straw returning（RT）,plow tillage with wheat straw returning（PTS）,and plow tillage without wheat straw returning（PT）.The effects of different tillage and straw management practices on soil structure,carbon and nitrogen fractions content,rhizosphere soil microbial community,greenhouse gas emission,peanut nodule nitrogen fixation,fate of fertilizer nitrogen,and peanut yield were systematically studied.In order to provide a scientific basis for the development of high yield,high efficiency,and environmentally friendly cultivation technology of summer peanut.The main results were as follows:1.The effects of tillage and straw management practices on soil propertiesUnder the same tillage practice,straw returning improved soil structure,enhanced the stability of aggregate,and increased the content of soil carbon fractions（TOC,EOC,DOC,and MBC）and nitrogen fractions（TN,MBN,NH₄⁺-N,and NO₃^?-N）,and improve the activity of soil enzyme（invertase,urease,catalase,and cellulase）.Under the same straw management practice,no-tillage increased the mass ratio of WSA_lm（2?8 mm）,the MWD and GMD,and soil carbon and nitrogen fractions content and promoted the improvement of soil enzyme activity at the 0?5 cm soil layer.However,no-tillage increased the stratification rate of soil TOC and TN content,resulting in the stratification phenomenon of"rich in the top and poor in the bottom",which was not conducive to the overall improvement of soil fertility.Under the same straw management practice,plow tillage reduced the SBD at the 0?30 cm soil layer and improved aggregate stability,soil TOC and TN storage,and soil enzyme activity at the 10?30 cm soil layer.2.The effects of tillage and straw management practices on rhizosphere soil microbial communityStraw returning increased the Chao1 index and Shannon index of bacterial and fungal communities,which indicated that the richness and evenness of bacterial and fungal communities in rhizosphere soil were improved by straw returning.Under the same straw management practice,no-tillage increased the Shannon index of fungal community.In the present study,Proteobacteria was the dominant phylum of bacterial community with the highest relative abundance,and Ascomycota was the dominant phyla of fungal community with the highest relative abundance.Straw returning increased the relative abundance of Mesorhizobium and Nitrospira.Redundancy analysis（RDA）showed that the content of DOC,NH₄⁺-N,and TOC were the main driving factors affecting the composition of bacterial community.The content of DOC,NO₃^?-N,and EOC were the main driving factors affecting the composition of fungal community.Therefore,different tillage and straw management practices drove the differences in bacterial and fungal community composition by regulating the content of carbon and nitrogen fractions in rhizosphere soil.3.The effects of tillage and straw management practices on soil greenhouse gas emissionIn the present study,the emission flux of CH₄ were both positive and negative,but almost all of them were negative,indicating that the soil acted as an uptake sink for CH₄ during the experiment period.Under the same straw management practice,the effects of different tillage practices on cumulative CO₂ emission were as follows:rotary tillage>plow tillage>no-tillage;the effects on cumulative N₂O emission were as follows:no-tillage>rotary tillage>plow tillage;and the effects on cumulative CH₄ uptake were as follows:no-tillage>plow tillage>rotary tillage.Therefore,under the same straw management practice,rotary tillage increased the GWP.In addition,straw returning increased the cumulative emission of CO₂ and N₂O,and decreased the cumulative uptake of CH₄.Thus,straw returning increased the GWP,but reduced the GHGI.4.The effects of tillage and straw management practices on peanut nodule nitrogen fixation and yieldStraw returning increased leghemoglobin content,nodule nitrogenase activity,and nodule nitrogen fixation,improved crop absorption and soil residue of nitrogen fertilizer,and reduced the loss of nitrogen fertilizer.Therefore,straw returning promoted nitrogen accumulation and yield increase of peanut.Under the same straw management practice,plow tillage promoted the improvement of nodule nitrogen fixation and increased the absorption of nitrogen fertilizer.Thus,the nitrogen accumulation was increased,and the pod yield and kernel yield were improved.In the 2022 growing season,compared with no-tillage with wheat straw mulching（NTS）and rotary tillage with wheat straw returning（RTS）treatment,plow tillage with wheat straw returning（PTS）treatment increased peanut pod yield by 8.23%and 6.19%,and increased kernel yield by 9.84%and 7.58%,respectively.In addition,for the yield sustainability index,plow tillage with wheat straw returning（PTS）treatment increased the pod and kernel yield sustainability index.In conclusion,PTS treatment was beneficial for improving soil productivity and increasing crop yield,reducing greenhouse gas emission intensity and fertilizer nitrogen loss,promoting sustainable development of agriculture,and is the optimal treatment for high yield,high efficiency,and environmental friendliness under the experimental conditions.