Maize-peanut intercropping led to an optimization of soil from the perspective of soil microorganism

Maize-peanut intercropping (M//P) is widely used in the North China Plain, but little is known about the changes in soil microorganism and its interactions with soil nutrient availability. Based on 3 years of field experiment, this study systematically investigated the soil microorganisms and soil properties in the 0–10 cm, 10–20 cm and 20–40 cm soil layers. This study found that M//P changed the soil microbial community composition compared to monoculture modes in all the studied soil layers but had the most effects in the 10–20 cm soil layer. Soil organic carbon, available phosphorus and available potassium explained the most variation in the microbial composition, while Proteobacteria, Acidobacteria and Planctomycetes were the phyla that were most affected by environmental factors. Based on the correlations and microbial function analysis, we speculated that: 1) M//P increased the relative abundance of Chlorobi, Parcubacteria and Chlamydiae, which promoted carbon and nitrogen metabolism; 2) M//P increased the relative abundance of Chlamydiae, Saccharibacteria, and Parcubacteria and then enhanced phosphonate and phosphinate metabolism, providing more available phosphorus for crops; 3) some KEGG pathways related to immunity and disease were increased in M//P, which may be related to disease control.