Abstract:Taking the continuous cropping substrate for two consecutive times as the object, we conducted the pot experiment to set up the solar disinfection, hot water disinfection, carbendazim disinfection, garlic associated cultivation, microbial agent and new substrate as control. After cucumber planting, we analyzed the changes of the physical and chemical properties, nutrient content, phenolic substance content, related enzyme activities of the substrate, as well as the changes of the growth and development, photosynthesis and fruit yield of cucumber in the fruiting period, to explore the mechanism of the effects of different treatments on the growth and development of cucumber in continuous cropping substrate cultivation, and to provide new ideas and methods for the reuse of waste substrate in production. The results showed that both solar disinfection and hot water disinfection treatments significantly increased the pH of the continuous cropping substrate and decreased the electrical conductivity value after cucumber cultivation in the continuous cropping substrate. The electrical conductivity value, available nitrogen, available phosphorus, available potassium, and total phenol content of the substrate treated with microbial bacteria were significantly lower than those of the continuous cropping substrate, while the substrate phosphatase and catalase activities were significantly higher than those of the continuous cropping substrate. In addition, hot water disinfection significantly reduced the total phenolic content and composite phenolic content of the continuous cropping substrate. When cucumber grew to fruiting stage, solar disinfection, hot water disinfection, carbendazim disinfection, garlic associated cultivation and application of microbial bacteria significantly enhanced the root activity and plant height of cucumber. The most significant increase in yield was observed in hot water disinfection and the application of microbial bacteria, which increased by 16.56% and 18.40% compared to continuous cropping substrate cultivation, respectively. It could be seen that both hot water disinfection treatment and application of microbial bacteria in continuous cropping substrate could reduce the accumulation of substrate salt, reduce total phenolic content, and significantly improve the root vitality and photosynthesis of cucumber, thereby increasing cucumber yield.