关键词: 荒漠草原, 补播, 土壤有机碳, 剖面分布, 粒径分布

Abstract: In order to explore the effects of reseeding on soil organic carbon and its distribution in desert steppe,the experimental plots were deep ploughed and reseeded using Agropyron mongolicum+A. desertorum(G),A. mongolicum (M) and A.desertorumS (S).The non-reseeded grasslands were used as control group (CK). The soil organic carbon and its distribution in soil profiles and different size of aggregates at 0~40 cm depth of each treatment were studied. The results showed that the contents of the total and aggregate organic carbon increased in grasslands of different reseeding treatments compared with the control grassland,especially at 30~40 cm depth. The soil organic carbon at 10~20 cm and 20~30 cm depth in grassland reseeded with A. desertorum were significantly higher than that of control grassland (P<0.05). For profile distribution,the soil organic carbon contents in all treated grasslands increased gradually with depth,and they were significantly higher at 30~40 cm depth than those at 0~10 cm depth (P<0.05). The contents of <0.053 mm aggregates organic carbon were the highest at each depth in different treated grasslands. The contribution of macroaggregates to soil organic carbon increased with depth. At 30~40cm soil layer,0.053~0.25 mm and >2 mm aggregates contributed more to total organic carbon. Overall,reseeding was conducive to soil organic carbon sequestration for degraded desert steppe. In this study,the effect of increasing soil organic carbon was obvious by reseeded with A. desertorum.

Key words: Desert steppe, Reseeding, Soil organic carbon, Profile distribution, Particle size distribution