Sugarcane/peanut intercropping system improves the soil quality and increases the abundance of beneficial microbes

Sugarcane/peanut intercropping is a highly efficient planting pattern in South China. However, the effects of sugarcane/peanut intercropping on soil quality need to be clarified. This study characterized the soil microbial community and the soil quality in sugarcane/peanut intercropping systems by the Illumina MiSeq platform. The results showed that the intercropping sugarcane (IS) system significantly increased the total N (TN), available N (AN), available P (AP), pH value, and acid phosphatase activity (ACP), but it had little effect on the total P (TP), total K (TK), available K (AK), organic matter (OM), urease activity, protease activity, catalase activity, and sucrase activity, compared with those in monocropping sugarcane (MS) and monocropping peanut (MP) systems. Both intercropping peanut (IP) and IS soils contained more bacteria and fungi than soils in the MP and MS fields, and the microbes identified were mainly Chloroflexi and Acidobacteria, respectively. Intercropping significantly increased the number of unique microbes in IS soils (68 genera), compared with the numbers in the IP (14), MS (17), and MP (16) systems. The redundancy analysis revealed that the abundances of culturable Acidobacteriaceae subgroup 1, nonculturable DA111, and culturable Acidobacteria were positively correlated with the measured soil quality in the intercropping system. Furthermore, the sugarcane/peanut intercropping significantly increased the economic benefit by 87.84% and 36.38%, as compared with that of the MP and MS, respectively. These results suggest that peanut and sugarcane intercropping increases the available N and P content by increasing the abundance of rhizospheric microbes, especially Acidobacteriaceae subgroup 1, DA111, and Acidobacteria.