Peanut/sorghum intercropping drives specific variation in peanut rhizosphere soil properties and microbiomes under salt stress

Intercropping can promote positive plant-soil interactions resulting in improved nutrient availability and ecological fitness, with microbes playing a key role. However, the specific effects of peanut/sorghum intercropping on soil properties and microbial community remain unclear, especially under salt stress conditions. In this study, sole-cropped peanut (SP) and intercropped peanut (IP) with sorghum in a field planting box experiment were performed under normal (N) and salt-stress (S, 0.25% NaCl) conditions, aims to investigate the specific response of peanut rhizosphere soil properties and microbial community to salt stress. The results showed that soil salinity negatively affects soil nutrient availability and enzymatic activities. To a certain extent, S-IP has a definite effect on the improvement of soil properties, and ammonium nitrogen (NH4+-N) increased 5.45%, total phosphorus (TP) increased 8.01%, soil organic carbon (SOC) increased 4.02%, soil peroxidase (POD) increased 8.15%, soil nitrate reductase (NR) increased 17.07%, and soil fructose-1,6-biphosphate aldolase enzyme (FDA) increased 16.26% compared with S-SP. Alterations of soil properties affect the microbial community structure and predicted function. Microbial community analysis revealed that the relative abundance of Massilia (5.79-times), Conocybe (47.43-times), Funneliformis (1.59-times), and Talaromyces (14.49-times) were significantly increased in S-IP compared to S-SP. Furthermore, the proportions of microbe associated with the saprotrophs were increased and pathogens were reduced in S-IP than in S-SP. Thus, peanut/sorghum intercropping under salt stress affects the potential functions of a microbial community by changing the soil properties and remodeling the microbial community, which had potential effects on improving the environmental adaptability and yield of peanuts.