Abstract:An experiment was conducted in 2017-2018 to explore the effects of potato starch processing wastewater irrigation on soil fertility characteristics, crop yield, and the regulatory effects of different fertilization on its fertilizer efficiency. 7 fertilization treatments were set:T1 (CK), no fertilization; T2, conventional fertilization; T3, optimized fertilization (reduced nitrogen and increased phosphorus); T4, optimized fertilization + oxygenator; T5, optimized fertilization 70% + bio-organic fertilizer; T6, optimized fertilization 70% + bio-organic fertilizer + oxygenator; T7, slow-release fertilizer (Wofte 26-10-12), soil nutrients and microbial counts were detected. The results showed that the contents of soil organic matter, available nitrogen, phosphorus and potassium of topsoil (0-20 cm) and subsurface soil (20-50 cm) were increased by 68.65% and 70.73%, 95.47% and 86.41%, 434.60% and 931.05%, 485.07% and 580.31% after 60 days irrigation and before planting compared to before irrigation. After harvest, soil nutrient contents were all decreased significantly and significantly different in different fertilizations. Meanwhile, fungi, bacteria and actinomycetes in topsoil were increased by 10, 50 and 1.5 times respectively, and total microbes increased by 34 times. Fungi was increased under different fertilization except T1, bacteria and total microbes were decreased, and actinomycetes was increased significantly after harvest. Among different fertilization, bacteria, actinomycetes and total microbes were highest under T5 and T6, and fungi was highest under T4. The height and aboveground biomass of both tested maize varieties were in the same sequence under different fertilization:T6>T5>T7>T3>T4>T2>T1. Hence, it can be concluded that potato starch processing wastewater has a certain fertilizer efficiency, and the fertilizer effect of potato starch wastewater can be effectively promoted by reducing the application of chemical fertilizer and increasing the application of organic fertilizer and oxygenator.