Cultivated grasslands present a higher soil organic carbon sequestration efficiency under leguminous than under gramineous species

The establishment of grassland on abandoned cropland has been proposed as an effective method of mitigating climate change by increasing soil organic carbon (SOC) storage. In this study, five cultivated grasslands were established (three leguminous species – Coronilla varia, Onobrychis viciaefolia, Medicago sativa, and two gramineous species – Poa annua, Agropyron cristatum), one uncultivated, one natural grassland to examine how the SOC storage, sequestration rate and sequestration efficiency to change for 5 years restoration in semi-arid area. Our results showed that the cultivated leguminous grasslands had greater total biomass, SOC storage, SOC sequestration rate and efficiency than gramineous grasslands. The greater soil carbon (C) accumulation in leguminous grassland was mainly attributed to higher biomass production. Leguminous grasslands accumulated more SOC than gramineous grasslands by 0.64 Mg C ha−1 yr−1. The average SOC sequestration efficiency in leguminous grassland (1.00) was about 2 times greater than gramineous grassland (0.34). The results indicate that cultivated leguminous grasslands sequestered more SOC with higher SOC sequestration efficiency than cultivated gramineous grasslands in arid and semi-arid areas.