Soil microorganism quantities and enzyme activities were studied in fields under wheat-cotton and garlic-cotton intercropping systems. Compared with cotton monoculture, both intercropping systems proved to be conducive to the proliferation of soil bacteria and actinomycetales and inhibited proliferation of fungi, the effects of the garlic-cotton intercropping system being more pronounced than those of the wheat-cotton intercropping system. Throughout the growth period of the cotton crop, soil urease activity and sucrase activity in 0-20 cm soil layer in the garlic-cotton intercropping system were significantly higher than in cotton monoculture, and the alkaline phosphatase activity in the garlic-cotton intercropping system was significantly higher than that in the cotton monoculture except at the flowering and blooming stages of cotton. The catalase activities in the garlic-cotton intercropping system at the seedling stage and boll-opening stage were significantly higher than in cotton monoculture. In the wheat-cotton intercropping system, soil urease activity and sucrase activity in the 0-20 cm soil layer at the seedling, flowering and boll stages of cotton were higher than in cotton monoculture, alkaline phosphatase activity at the bud stage was significantly higher than in cotton monoculture, and catalase activity at the seedling and boll opening stages was significantly higher than in cotton monoculture. In conclusion, the garlic-cotton and the wheat-cotton intercropping systems can increase the quantities of soil bacteria and actinomycetales, thus effectively suppressing the occurrence of succession cropping obstacles in cotton fields, and they also increase the activities of soil-related enzymes, which is good for creating healthy soil in cotton fields.
