Effects of different rotation crops on soil physicochemical properties and microbial community structure in continuous cotton fields.

Cotton monoculture is widespread in the oasis cotton-growing region of Xinjiang. Long-term continuous cropping has led to declines in soil fertility and imbalances in microbial communities, constraining sustainable, green production. Crop rotation is an effective agronomic practice to mitigate the deleterious effects of continuous cropping; however, the selection of rotation crops and the regulatory mechanisms by which rotation reshapes the soil micro-ecology require systematic clarification. Using continuous cotton (CK) cropping as the control, we combined high-throughput amplicon sequencing with soil physicochemical analyses to evaluate the effects of four previous-crop schemes-cotton → peanut (CPC), cotton → soybean (CSC), cotton → rapeseed (CRC), and cotton → maize (CMC)-on soil properties and the microbial community structure. Relative to CK, the CPC, CSC, and CRC treatments led to significantly reductions in yield and gross output value ranging from 38.72 to 62.23% and 34.54 to 55.35%, respectively. Although the net profit under CPC treatment decreased by 36.27% relative to CK, the benefit-cost ratio showed no significant difference. CPC significantly increased soil organic matter, available phosphorus, NH4