Effects of Maize-Peanut Intercropping on Rhizosphere Microecological Environment and Yield of Peanut
Continuous cropping seriously affected the growth of peanut plants,resulting in decreased yield and quality.Intercropping,as a combined planting mode,is a safe,effective and ecological method to alleviate continuous cropping obstacles.In order to further investigate the effects of maize-peanut intercropping on rhizosphere microecological environment and yield of peanut,the fields of continuous cropping peanut for 10 years in Juxian County of Shandong Province were selected,'Huayu 22'and'Zhengdan 958'were used as experimental materials,and the intercropping mode of maize and peanut at 3∶4 was set with continuous cropping peanut as control.The effects of maize-peanut intercropping on nitrogen,phosphorus,potassium and organic matter contents and microbial community structure in rhizosphere soil,and pod yield of peanuts were studied.The effects of maize root exudes and maize rhizosphere microorganisms on the growth and rhizosphere microbial community structure of continuous cropping peanut were investigated through laboratory simulation experiments.The results of field experiment showed that compared with continuous cropping peanut,maize-peanut intercropping significantly increased the contents of orgnic matter,alkali hydrolytic nitrogen,available phosphorus and available potassium,significantly increased the abundance of Actinospica,Granulicella,Bry-obacter and Chujaibacter while significantly decreased the abundance of Bradyrhizobium and Mesorhizobium in the rhizosphere soil of peanut.The 100-pod weight of intercropped peanut increased significantly by 41.8%,the rotten pod number per plant decreased significantly by 66.7%,and the pod yield increased significantly by 32.2%.The results of laboratory simulation experiments showed that adding maize root exudate and rhizosphere microorganism could increase the abundance of Actinospica in rhizosphere soil and significantly promote root growth of continuous cropping peanut;Maize root exudate treatment significantly increased the peanut above-ground dry weight by 24.1%,while the root length and root surface area increased only by 7.2%and 5.4%.Maize rhizosphere microorganism treatment increased the peanut above-ground dry weight by 4.7%and in-creased the root length and root surface area by 50.5%and 47.4%,respectively.In conclusion,maize-peanut intercropping could improve the availability of soil nutrients and the structure of microbial community in peanut rhizosphere,reduce rotten pod number and thus increase peanut yield.Maize root exudates and maize rhizo-sphere soil microorganism in maize-peanut intercropping system played an important role in improving the soil ecological environment of continuous cropping peanut,and were one of the main factors to alleviate the obsta-cles of continuous cropping peanut.