Effects Of Different Intercropping Of Maize And Soybean On AMF Colonization And Greenhouse Gas Emission

Intercropping is an important agricultural measure to improve land use and crop yields,among which maize and soybean intercropping has typical features like high yield,high efficiency,improving soil quality,reducing greenhouse gas emission and sustainable development,etc.Arbuscular mycorrhizal fungi?AMF?are important microbial resources,which play an important role in promoting crop growth,enhancing plant stress resistance,and improving soil quality.In addition,intercropping,as a planting pattern worthy of promotion,is not comprehensive enough in greenhouse gas emission.Therefore,the field experiment were consisted of maize/soybean intercropping system,monoculture maize and monoculture legume.The purpose is to explore the marginal effect of maize and soybean intercropping with different row ratio,combine the dry matter accumulation and distribution,find out the influence of different crop ratio on the marginal effect,define the scope and intensity of the marginal effect,and summarize the regularity between the marginal effect and the dry matter distribution.Besides,to explore the periodicity of AMF growth and symbiosis with crops under different planting patterns in agriculture land,as well as the glomalin production of AMF.In addition focusing on the regulation of greenhouse gas emission,and the correlation between soil factors and greenhouse gas emissions.The main results are as fallows:The experiment showed that compared with monoculture,intercropping had a positive effect on maize dry matter accumulation,during big flare to maturity stage;but had a negative effect on soybean dry matter accumulation at filling stages.The border-middle-and internal row in intercrops of maize and the middle-and internal row in intercrops of soybean produced more dry matter accumulation rate and amount than the respective intercrops of maize and soybean,but the intercropping decreased the border dry matter accumulation rate and amount of soybean.the land equivalent ratio?LER?of intercropped treaments were all above 1,and maize showed competitive advantage over soybean.During the growth period,the stem and leaf dry matter of maize and soybean reached the maximum at 55 days after sowing.The remobilization of maize leaf,maize stem and soybean stem and leaf were 10.48-20.67 g p^-1,18.77-33.70 g p^-1 and 3.29-9.72 g p^-1,respectively.The efficiency rates were 15.45-29.44%,33.62-62.96%,14.05-26.92%,and the conversion rates were 9.82-22.09%,18.07-32.30%and 13.08-37.25%,respectively.The mycorrhizal colonization and colonization density and hypha density increased gradually with the symbiotic between AMF and crops,in the milking stage of maize?the filling stage of soybean?.The mycorrhizal arbuscular richness increased rapidly in the silking stage of maize?the flowering stage of soybean?,and then decreased.With the growth of crop,the spore density of AMF increased from 269.40 spore 100g^-1to 1484.20spore 100g^-1,the content of easily extractable glomalin increased from 430.88 ug g^-1 to600.78 ug g^-1,and the content of total glomalin increased from 942.59 ug g^-1to 1304.03 ug g^-1.Intercropping of maize and soybean improved the colonization efficiency of AMF,the mycorrhizal colonization,colonization density,arbuscular richness of mycorrhiza and the soil hypha and spore density and glomalin content of intercropping treatments were higher than those of monoculture.The marginal effect has been found in symbiosis between AMF and crops in intercropping system.During two years,the hypha density,spore density,easily extractable glomalin,total glomalin of maize in intercropping treatments showed an increase,as the distance of maize further away from soybean.The correlation analysis showed that there was a close relationship among mycorrhizal colonization,colonization density,arbuscular richness,hypha and spore density,and glomalin content,as well as,the correlation coefficient was above 0.51.Maize and soybean intercropping reduced the emission rate of CO₂ and N₂O,and reduced the absorption rate of CH₄.The N₂O and CO₂emission peak was formed when apply fertilize so the apply of fertilize had an effect on the emission rate.The CH₄emission rate was generally low in different planting pattern,the range was-1.19-0.94?g CH₄-C m^-2 h^-1.In intercropping system,soybean belt?IS?has the highest N₂O,CO₂emission rate,followed by maize belt?IM?,the junction belt?IJ?was the lowest.Compared with monoculture,IM and IS showed decreased GWP by 27.4%and 10.0%,respectively.The GHGI of intercroping was lower than monoculture soybean?MS?and higher than monoculture maize?MM?.Among the impact to greenhouse gas emission,the NO₃^-,NH₄⁺content exerted the highest influence to CO₂ emission,correlation coefficient values were both 0.32;the NO₃^-content exerted the highest influence to N₂O emission,correlation coefficient values was 0.50;only soil water content has a direct effect on CH₄ emission,correlation coefficient values was 0.13.