The ageing of orchards is common in the apple planting process, which affects the yield and quality of apples, as well as the development of the apple industry and local economy. The investigation of soil properties is important to the improvement and soil management of aged apple orchards. In this study, we investigated the spatial distribution, correlation and clustering of soil properties (nutrients, pH, enzymes and microorganisms) in aged and non-aged apple orchards, as well as soil microbial communities in aged orchards with and without biofertilizer (Bacillus mucilaginosus + N, P, K) in Luochuan, Loess Plateau. The results showed that most soil properties, except for pH and catalase activity, decreased gradually with depth of soil and were highest in the 0–40 cm layer in both the aged and non-aged orchards. However, there were no obvious differences in the horizontal direction, especially in the aged orchards, indicating that the fertilizer application site was randomly located in the aged orchards. The significant correlations between soil nutrients and microbes, available phosphorus and tree age, and the clustering of orchards as aged and non-aged groups by soil properties, indicated that soil properties should be monitored in a timely manner to assess fertilizer application and predict the ageing of orchards. Additionally, the biofertilizer might make the aged orchard soil tend to non-ageing by increasing beneficial and reducing harmful microbes, which suggested that biofertilizers should be widely used in future fertilizer application management of aged orchards to delay ageing.

中文翻译：

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黄土高原洛川县陈化与未陈化苹果园土壤生化特性及微生物组成

果园老化现象普遍存在于苹果种植过程中，影响到苹果的产量和品质，也影响到苹果产业和地方经济的发展。土壤性质的调查对老年苹果园的改良和土壤管理具有重要意义。在这项研究中，我们调查了老化和未老化苹果园土壤特性（养分、pH、酶和微生物）的空间分布、相关性和聚类，以及使用和不使用生物肥料（Bacillus mucilaginosus）的老化果园的土壤微生物群落。 + N, P, K) 在黄土高原洛川。结果表明，除 pH 值和过氧化氢酶活性外，大多数土壤性质随着土壤深度逐渐降低，在老化和未老化果园的 0-40 cm 层中最高。但在水平方向上并无明显差异，尤其是陈年果园，说明施肥地点随机分布在陈年果园内。土壤养分和微生物、有效磷和树龄之间的显着相关性以及果园按土壤特性划分为老化组和未老化组的显着相关性表明，应及时监测土壤特性以评估施肥和预测老化果园。此外，