Abstract:In order to unravel effects of heat treatment on biological effect of soil and nutritional medium, we heated soil and nutritional medium on which cucumber were successively planted for 12 times at 55 ℃ and 75 ℃ both for 48 h and 96 h, and then analyzed the characteristics of growth rate of cucumber, soil enzyme activities, soil microbial community and soil nutrients. The results showed that heat treatment significantly enhanced cucumber growth rate for both soil and nutritional medium, and alleviated the symptoms of continuous cropping obstacle; heat treatment significantly increased the activities of catalase, neutral phosphatase and sucrose, the number of bacteria and actinomycetes, and soil organic matter contents, total nitrogen, alkali-hydrolyzale nitrogen and available potassium, while decreased the number of soil fungi. However, short-time heat treatment at 55 ℃ increased the activities of catalase, neutral phosphatase and the amounts of bacteria and actinomycetes, while decreased the activities of sucrose and urease, the number of fungi, soil total nitrogen, alkali-hydrolyzale nitrogen and available potassium in nutritional medium. In conclusion, heat treatment can alleviate continuous cropping obstacle, especially for the treatment at 55 ℃ for 96 h. This study provided a theoretical and technical basis for restoration and reuse of the vegetable crop nutrient medium repair and recycled.