Intercropping peanut with traditional Chinese medicinal plants improves soil microcosm environment and peanut production in subtropical China
Many environmental issues affect peanut production in continuous monocropping system. Deterioration of soil microbial communities, especially for decrease in fungal diversity and increase in fungal pathogens, is widely hypothesized as a key factor for decreasing peanut production. In this study, a pot experiment was conducted to investigate the changes in soil microbial communities and peanut yield under the scheme of peanut intercropped with traditional Chinese medicinal plants, including
Atractylodes lancea, Dioscorea zingiberebsis, Euphorbia pekinensis, Ophiopogon platyphyllum and Pinellia ternate. The results showed that soil microcosm environment was improved, and the fungal diversity and fungal pathogens such as Fusarium sp. and Verticillium sp. were restrained when peanut intercropped with A. lancea and E. pekinensis. The DGGE analysis of 18S-rRNA from DNA of the total soil communities showed obvious transferring of species of fungi between peanut monocropping and the intercropping systems. Compared with the control, the superoxide dismutase activity of peanut was increased by 43% in A. lancea and 37% in E. pekinensis intercropping systems, along with 37 and 16% yield improvement of peanut, respectively. Based on the result of the pot experiment, A. lancea and E. pekinensis were intercropped with peanuts in a field experiment. A considerable agreement was found between the results obtained from the field and pot experiments. Compared with peanut monocropping system, colony form unit of mould decreased by 31% in A. lancea and 18% in E. pekinensis intercropping treatments, where peanut yields were respectively increased by 39 and 35%. Further research should include integrated PCR-DGGE analysis to determine the transfer of peanut soil-born pathogens and its mechanism, and the optimization of intercropping system and planting density of medicinal plants to obtain the best benefits, and the understanding of the long-term effect of the intercropping systems.