Vegetation and species impacts on soil organic carbon sequestration following ecological restoration over the Loess Plateau, China

摘要

Extensive soil organic carbon (SOC) accumulation has been reported following ecological restoration on the Loess Plateau of northwest China. While previous studies have found the restoration age to be a major factor controlling SOC change, potential effects of vegetation type and plant species have been largely neglected. Here, we compiled a database of 331 measurements of SOC changes following cropland restoration across the entire Loess Plateau. Results from stepwise multiple linear regressions indicated dominant contributions by restoration age, vegetation type or plant species, and/or their interactions in post-restoration SOC accumulation, accounting for 67-86% of the variation in SOC sequestration being explained by the model. Of the four restoration types examined, managed grassland was found to have the highest SOC sequestration rate (0.41 Mg C hm(-2) yr(-1)), followed by plantation (0.27 Mg C hm(-2) yr(-1)) and shrubland (0.25 Mg C hm(-2) yr(-1)), with the lowest value found for naturally recovered grassland (0.13 Mg C hm(-2) yr(-1)). The different SOC sequestration capacities for these vegetation types were further confirmed by an independent mechanistic modeling approach based on SOC turnover rate. Our results highlight the critical role of plant type in determining SOC sequestration following revegetation over cropland. Such management-relevant information should be considered in future restoration efforts.