Soil biochemical properties and microbial composition in aged and non‐aged apple (Malus domestica) orchards in Luochuan County, Loess Plateau, China

Abstract

AbstractThe 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.