[Effects of Bacillus fertilizer and agent on growth of young peach tree and soil environment under replant condition.]

We analyzed the effects of Bacillus fertilizer and agent supplementation at different concentrations in the replanted soil by examining the growth of young peach trees, soil nutrients, enzyme activities, and fungal commu-nity. The aim of this study was to provide theoretical basis for alleviating peach replant diseases. One-year-old potted 'Yuanmeng' peach trees were subjected to eight treatments: replanted soil without supplementation (RS), non-replanted soil without supplementation (NS), replanted soil with 1%, 4%, 8% Bacillus fertilizer supplementation (BF1, BF2, BF3), and 0.1‰, 0.5‰, 1‰ Bacillus agent supplementation (B1, B2, B3), respectively. The results showed that shoot growth and root biomass under NS treatment were greater than that under other treatments, and the contents of soil organic matter, available nutrients and soil catalase activity were greatly enhanced. Peach trees treated with BF and B treatments showed better root development than RS, among which, BF3 and B1 treatments were the best, and B1 treatment had similar effects as NS treatment. Compared with RS, BF and B treatments significantly increased the activities of soil catalase and urease during new shoot development, while B treatment significantly increased soil sucrase activity after the growth cessation of new shoots. Bacillus fertilizer and agent increased soil fungal diversity and the relative abundance of Ascomycota, Chaetomium and Penicillium, and decreased that of Basidiomycota. Considering the comprehensive parameters, BF3 and B1 showed more significant effects. In summary, our findings indicated that the supplementation of Bacillus fertilizer and agent to replanted soil could improve soil fertility, fungal community, and root development of roots, and thus provided a feasible method to alleviate peach replant diseases.研究向桃树连作土壤中添加芽孢杆菌菌肥和菌剂对再植幼树生长、土壤养分、酶活性和真菌群落的影响,可为缓解桃树连作障碍提供理论依据。在盆栽条件下,以一年生普通桃‘圆梦'和连作10年的桃园土壤为试材,设置8个处理,即连作土常规处理(RS)、客土常规处理(NS)、连作土常规处理基础上分别添加1%、4%、8%的芽孢杆菌菌肥(BF1、BF2、BF3),及分别添加0.1‰、0.5‰、1‰的芽孢杆菌菌剂(B1、B2、B3)。结果表明: NS处理的桃幼苗地上部和地下部生长指标、土壤有机质和速效养分含量、土壤过氧化氢酶活性显著高于其他处理。在连作土壤中加入不同浓度的芽孢杆菌菌肥和菌剂可促进桃幼树根系发育,其中B1和BF3处理的效果较好,且B1处理的促进效果与NS处理无显著差异。与RS相比,芽孢杆菌菌肥和菌剂处理显著提高了新梢生长高峰期的土壤过氧化氢酶、脲酶活性,菌剂处理显著提高了新梢停长期的蔗糖酶活性。在新梢停长期,菌肥和菌剂处理后土壤真菌群落多样性显著提高,子囊菌门、毛壳属、青霉属的相对丰度显著上升,担子菌门相对丰度显著下降。综合各项指标,B1和BF3的作用较显著。综上,桃树连作土壤施用一定量的芽孢杆菌菌肥和菌剂能改善土壤真菌群落结构,提高土壤肥力,促进树体根系发育,为缓解桃树连作障碍提供了可行方案。.