Effects of Long Term Rice-rice-rape Rotation on Soil Physicochemical Properties and Microbial Community Structure

YANG Jinglin; LI Lin; HU Deyong

doi:10.15933/j.cnki.1004-3268.2017.09.008

Abstract：To explore the effect of rice-rice-rape rotation on soil physicochemical properties and microbial community structure in hilly area of southern China,the soil microbial biomass and composition of two kinds of different tillage systems[long rice-rice-rape rotation(DDY) and rice-rice continuous cropping(DD)] after 30 years of rotation were analyzed by PLFA marker spectrum analysis method,and the soil physicochemical properties during three periods(including the mature stages of early rice,late rice and oilseed rape) were studied.The results showed that compared with DD treatment,the contents of total N and total P and pH value of DDY treatment decreased,there was a significant defference for total N content,the total N content of DDY treatment significantly decreased by 50.76%,46.67%,49.62%;the total K content of DDY treatment increased,but the difference was not significant;the contents of organic matter,alkali-hydrolyzable N,available P,available K showed dynamic changes.Soil microbial PLFA marker test showed that compared with DD treatment,soil microbial PLFA amount of DDY treatment increased by 19.69%,20.20% and 49.12% at three different determination stages,respectively;the bacterial PLFA amount of DDY treatment increased,the fungi PLFA amount of DDY treatment decreased,and the ratio of fungi PLFA amount to bacteria PLFA amount of DDY treatment decreased.The principal component analysis of microbial PLFA showed that rotation obviously influenced the microbial community structure,the amount of bacteria and fungi were mainly affected by two tillage methods.Overall,the long term rice-rice-rape rotation promoted the decomposition of total N and P,significantly improved the microbial biomass,especialy bacteria,significantly decreased the fungal biomass,significantly increased the ratio of bacteria to fungi.