[Analysis of Bacterial Community Characteristics in Maize Root Zones Under Maize-soybean Compound Planting Mode].

Abstract

Maize-soybean compound intercropping has the potential to increase yield and is being tested for spreading in Huang-Huai-hai Plain. However, the main regulatory regions of this cropping pattern on soil microbial communities have not been clarified. In the present study, the tested samples were collected from three maize root zones of bulk soil, rhizosphere soil, and roots under mono- and intercropping planting modes, respectively. The non-rhizosphere soil chemical properties and enzyme activities were determined, and bacterial communities were characterized using high-throughput sequencing of the 16S rRNA gene V3-V4 region. Compared with monocropping, the maize bulk soil electric conductivity （EC）, soil organic matter （SOM）, available potassium （AK）, available phosphorus （AP）, total nitrogen （TN）, and enzyme activities of intercropping were significantly increased. The α diversities and β diversity of the bacterial community in rhizosphere soil were significantly different between the two planting modes. There were 11 bacteria genera with significantly higher abundance in the rhizosphere soil of compound planting than that of monoculture, and TN, AP, and catalase were the three most important factors contributing to their distribution. The abundances of 8 genera among the 11 genera mentioned above, unclassified Vicinamibacterales, unclassified Geminicoccaceae, MND1, unclassified Gemmatimonadaceae, Acidibacter, unclassified Vicinamibacteraceae, Sphingomonas, and unclassified Comamonadaceae were significantly positively correlated with TN. As for the bacteria distribution in maize root, AK contributed the most and had a significantly negative correlation with unclassified Rhizobiaceae and unclassified Microscillaceae and a positive correlation with Haliangium. Maize-soybean compound intercropping affected mainly the bacterial community of maize rhizosphere and had an evident effect on soil fertilizer cultivation and microbial diversity regulation, which provides a theoretical basis and practical guidance for rational intercropping to maintain agroecosystem biodiversity.