Topsoil carbon sequestration of vegetation restoration on the Loess Plateau

Abstract

Vegetation restoration plays an important role in enhancing soil organic carbon (SOC) sequestration. However, there are diverse types of vegetation restoration with different SOC sequestration rates. Understanding the dynamic of SOC at topsoil (0–20 cm) and potential problems of the different types (i.e., woodlands, shrub lands, artificial grasslands, orchards, and abandoned lands) are important for future sustainable development. We surveyed 73 peer-reviewed studies conducted on the Chinese Loess Plateau from 2000 to 2019. The relative change in SOC stock under shrub lands, woodlands, and abandoned lands performed significantly and positively related to restoration time (P < 0.001). The rate was highest for shrub lands (0.55 ± 0.45 t ha−1 yr−1) compared to that of other restoration types. The Robinia pseudoacacia, a typical N-fixers, sequestrate more SOC (3.84% yr−1) than other tree species (1.18% yr−1). Orchards and artificial grasslands, however, were based on the relatively weak relations between restoration age and SOC stock with the low efficiency of SOC stock change (19.0 ± 32.1% and 20.2 ± 35.2% respectively overall time). The restoration age, initial SOC stock, and temperature significantly influenced the relative change in SOC stock (P < 0.001). In addition, the shrub lands remained inert to the temperature and precipitation (P > 0.05), indicating its wide adaptability on the Loess Plateau. We conclude that restoration types and environmental factors control SOC dynamic, and must be considered for the vegetation restoration types.