关键词: 苹果, 连作障碍, 棉隆熏蒸, 短期轮作葱, 真菌群落结构, 土壤酶

Abstract: In order to provide basis for preventing and controlling apple replant disease，the Malus hupehensis Rehd.，which was planted in a Allium fistulosum rotation after dazomet fumigation under pot condition，was tested to study the effect on the soil environment and the growth of its seedling. Experiments were begun to conduct in May 2015，and four treatments were：soil of old apple orchard， Allium fistulosum rotation，dazomet fumigation，and Allium fistulosum rotation after dazomet fumigation. The seedlings of M. hupehensis Rehd. for all treatments were planted in May 2016. The results showed that，compared Allium fistulosum rotation after dazomet fumigation with the control in 2015，the fungi number was reduced by 73%；the copy number of Fusarium proliferatum which was analysised by Real-time PCR was reduced by 67%；the number of bacteria was reduced by 19%；the ratio of bacteria and fungi was increased by 213%. The results of principal component analysis of T-RFLP（PCA）and cluster analysis showed that，Allium fistulosum rotation after dazomet fumigation significantly changed soil fungal community structure. Compared with dazomet fumigation，the soil enzyme activity（urease，sucrase，catalase，phosphatase）of Allium fistulosum rotation after dazomet fumigation was increased. In August 2016，compared with the control，the plant height，stem diameter，fresh weight and dry weight of M. hupehensis Rehd. seedlings with a Allium fistulosum rotation after dazomet fumigation were 1.96，1.75，2.31 and 2.34 times those of the control，respectively，and the root length，root area，root volume，root respiration rate were increased by 155%，310%，294% and 89%，respectively. The treatment with a short time Allium fistulosum rotation after dazomet fumigation had the highest ratio of bacteria and fungi，significantly changed the soil fungal community structure，improved soil enzyme activity，promoted the growth of M. hupeheusis Rehd.，and had the better function in prevention and control of apple replant disease than that of dazomet fumigation，therefore，it could be an effective measure to reduce apple replant disease.

Key words: apple, replant disease, dazomet fumigation, short-time Allium fistulosum rotation, fungal community, soil enzyme activity