Objective Explore the improvement effect of microbial microbial agent on cotton continuous cropping soil and its influence on cotton yield and quality.

Methods Conventional fertilization was used as the control group, and three microbial microbial agents, "Oasis No. 1" (S1), "salt solution capsule" (S2), and composite microbial microbial agent (S3) were selected as the three experimental groups, and afterwards field tests were carried out in long-term continuous cropping saline-alkali cotton fields.

Results The results showed that S2 had the best soil improvement effect. Compared with conventional fertilization, soil enzyme activity was significantly increased, soil organic matter and AP were increased by 30.83% and 55.19%, respectively, and the soil total salt content decreased by 46.09%. The best effect on cotton growth was S3. Compared with conventional fertilization, the root activity and nitrate reductase activity of cotton leaves significantly increased, chlorophyll content significantly increased, and malondialdehyde content significantly decreased. Compared with the control, the cotton yield and quality of S3 treatment were significantly increased, the lint and seed cotton yields were significantly increased by 20.13% and 37.76%, respectively, the cotton fiber strength and length were increased, the uniformity was improved, and the short fiber index was decreased.

Conclusion Microbial microbial agent S3 has the best effect on improving continuous cropping cotton field obstacles, and can improve soil physicochemical properties and increase cotton yield.