Influence of aerially seeded Pinus massoniana plantations on soil quality in severely eroded and degraded land of subtropical China

Abstract

Vegetation restoration is widely used to reduce soil erosion and control soil degradation, which is conducive to improving soil quality. Aerial seeding is an effective vegetation recovery method that has been applied in large areas with severe soil erosion in China. Pinus massoniana is not only a typical native coniferous tree species, but also a pioneer tree species for vegetation recovery in subtropical China. This study evaluates the soil quality of aerially seeded P. massoniana plantations of different stand ages and examines the vegetation factors affecting soil quality. Principal component analysis and Pearson correlation analysis were used to determine the minimum data set (MDS) for developing a soil quality index. The relationship between soil quality and vegetation factors was analyzed using redundancy analysis. The MDS was established with soil bulk density, field water capacity, non-capillary porosity, total nitrogen, soil organic matter, and pH. The results showed that the soil quality significantly increased with vegetation recovery age at 0–20 and 20–50 cm soil depths. The soil quality of the surface layer was mainly affected by understory vegetation and litter, whereas that of the deep layer was mainly affected by trees. Therefore, the appropriate management of P. massoniana forest, achieved by appropriately extending forest management rotation, replanting broad-leaved trees, and minimizing the damage to understory vegetation and litter, is essential for effectively improving soil quality.