Compost amendment reportedly improved apple tree growth in replant soils. However, its effects should be evaluated at different soil depths and locations. This study investigated the impact of soil improvement with compost on soil physicochemical properties and bacterial community structure of a replanted apple orchard in comparison with the original orchard without compost improvement. The V1–V3 region of the bacterial 16S rRNA gene was subjected to high-throughput 454 pyrosequencing, and data were analyzed using the Mothur pipeline. The results showed that the soil improvement benefited tree growth and fruit quality during the study period. The compost amendment markedly increased tree height and stem diameter by a range of 6.1%–21.0% and 4.0%–14.0%, respectively. Fruit yield (9.5%), average weight (9.6%), and soluble solid content (5.6%) were also increased by compost amendment compared to those of the unimproved treatment. The pH, organic matter, and available N, P, and K contents were significantly increased by 5.7%–21.9%, 0.2%–62.9%, 9.3%–29.3%, 36.7%–64.5%, and 17.2%–100.3% in the compost improved soil. The pyrosequencing data showed that the soil improvement changed the bacterial community structure at all soil depths (0–20 cm and 20–40 cm) and locations (in-row and inter-row) considered; e.g., the relative abundance of Proteobacteria (20.2%), Bacteroidetes (2.5%), and Cyanobacteria (1.0%) was increased while that of Chloroflexi (5.5%), Acidobacteria (5.2%), Nitrospirae (4.5%), Gemmatimonadetes (3.8%), and Actinobacteria (1.8%) was decreased. The relative abundance of some dominant genera Burkholderia (2.3%), Pseudomonas (1.0%), and Paenibacillus (0.5%) were enhanced in the compost improved soil. Moreover, other dominant genera such as Nitrospira (6.4%), Gemmatimonas (2.2%), and Phenylobacterium (0.3%) were reduced by the application of compost. Our results indicate that soil improvement benefits the growth of tree and fruit quality, and is likely mediated by increased soil pH, organic matter, and available nutrient contents and beneficial bacterial community composition.

据报道，堆肥改良可改善补种土壤中苹果树的生长。但是，应在不同的土壤深度和位置评估其影响。这项研究调查了堆肥改良土壤与未堆肥改良原始苹果园相比，对复种苹果园土壤理化性质和细菌群落结构的影响。对细菌16S rRNA基因的V1-V3区域进行了高通量454焦磷酸测序，并使用Mothur管道分析了数据。结果表明，在研究期间，土壤改良有利于树木生长和果实品质。堆肥的改良显着增加了树高和茎径，范围分别为6.1％–21.0％和4.0％–14.0％。水果产量（9.5％），平均重量（9.6％）和可溶性固形物含量（5。与未经改良的处理相比，通过堆肥改良的比例也增加了6％）。pH，有机质和有效氮，磷和钾含量分别显着增加了5.7％–21.9％，0.2％–62.9％，9.3％–29.3％，36.7％–64.5％和17.2％–100.3％堆肥可以改善土壤。焦磷酸测序数据表明，土壤改良改变了所有土壤深度（0–20 cm和20–40 cm）和所考虑的位置（行内和行间）的细菌群落结构；例如，Proteobacteria（20.2％），Bacteroidetes（2.5％）和Cyanobacteria（1.0％）的相对丰度增加，而Chloroflexi（5.5％），Acidobacteria（5.2％），Nitrospirae（4.5％），Gemmatimonadetes（3.8） ％），放线菌减少（1.8％）。在堆肥改良的土壤中，某些优势属伯克霍尔德氏菌（2.3％），假单胞菌（1.0％）和芽孢杆菌（0.5％）的相对丰度增加了。此外，其他优势属如硝化螺旋藻（6.4％），芽孢杆菌（2.2％）和苯细菌（0.3％）通过堆肥减少。我们的结果表明，土壤改良有利于树木和果实品质的增长，并可能由土壤pH值，有机质，有效养分含量和有益细菌群落组成的增加而介导。