Mineralization characteristics of soil organic carbon under different herbaceous plant mosaics in semi-arid grasslands

We aimed to explore the mineralization characteristics of soil organic carbon(SOC) under different plant species in semi-arid grassland and provide basic soil carbon cycling data. Leymus chinensis, Stipa krylovii Roshev, Artemisia frigida, and Agrophorn cristam (L.) Gaertn were selected as the plant species. Incubation experiment were conducted on SOC mineralization in soil aggregates with particle sizes of > 2, 1–2, 0.25–1, and < 0.25 mm. The cumulative SOC mineralization amount in L. chinensis with a particle size > 2 mm was the highest, exceeding that of A. cristam (L.) Gaertn by approximately 136.14%. S. krylovii Roshev (70.73%), L. chinensis (58.05%), and A. frigida (33.73%) exhibited pronounced promotion effects on mineralization. The potential SOC mineralization of S. krylovii Roshev was the greatest among all species at the same soil particle size. The potential SOC mineralization was highest at a particle size of > 2 mm for all plant types. All plant types increased the SOC mineralization rate and cumulative mineralization in soils with large particle sizes, the mineralization reaction occurred more strongly. Organic carbon cumulative SOC mineralization rapidly increased in all tests during the first 20 days and gradually slowed thereafter.