[Effects of residual apple fermentation products on continuous cropping soil environment and the growth of Malus hupehensis Rehd. Seedlings].

Effects of fermented apple products on the growth of continuous cropping Malus hupehensis Rehd. seedlings and soil environment were examined in a pot experiment to provide theoretical basis for apple replant disease. There were four treatments, the replanted soil (control, CK), sterilized replant soil (T), replanted soil applied with apple fermentation products (T), and replanted soil applied with sterilized apple fermentation products (T). The results showed that T, T and T significantly promoted seedlings growth, with better performance of T and T. T increased root respiration rate, plant height, ground diameter, fresh weight, and dry weight by 107.3%, 50.6%, 42.4%, 171.7%, 225.3%, while T increased them by 104.4%, 50.6%, 42.3%, 171.8%, 225.5%, respectively over CK. T and T increased the activities of nutrient conversion-related enzymes in continuous cropping soil. T increased the activities of catalase, urease, neutral phosphatase and sucrase by 44.5%, 169.5%, 23.4%, 169.3%, while T increased them by 23.7%, 72.6%, 1.5%, 121.5%, respectively. Catalase and sucrase activities under T treatment did not differ from that in CK, whereas their urease and neutral phosphatase activities were reduced by 40.8% and 41.6%, respectively. The contents of ammonium, nitrate, available phosphorus and available potassium in T soil were increased by 18.6%, 50.6%, 14.0% and 36.7% respectively. T only increased the content of available nitrogen, with ammonium and nitrate being increased by 7.0% and 23.6% respectively. The content of available nutrients of T decreased compared with CK. T and T significantly reduced the abundance of actinomycetes and fungi in soil and increased that of bacteria. The abundance of bacteria, actinomycetes and fungi in T treatment were all significantly decreased. Results of real-time fluorescence quantitative PCR analysis showed that the gene copies of Fusarium proliferaturn, F. moniliforme, F. solani and F. oxysporum in T, T and T were ecreased to different degrees. Apple fermented product could inhibit soil pathogen in replanted orchard soil, improve soil environment, and promote seedling growth, which could be used to alleviate the apple replant disease.