草原恢复时土壤有机矿质复合体中结合态腐殖质变化

Variation of Combined Humus in Soil Organo-mineral Complexes in Process of Grassland Restoration

从退化草原恢复前后的土壤样品中，提取各粒级土壤有机矿质复合体，用不同浸提剂提取表征不同结合状态的腐殖质，对其含量、分布和组成在草原恢复过程中的变化进行了分析，得出了土壤各粒级复合体中腐殖质主要以松、紧结合形式存在；它大部分分布在粘粒和粗、细粉粒级复合体中；草原恢复时土壤腐殖质的增加主要是粘粒和粗、细粉粒级复合体中松态腐殖质的贡献，其次是稳态腐殖质；而松态腐殖质的增加主要是ＨＡ 的增加，稳态腐殖质的增加主要是ＦＡ 的增加。

Soil organo-mineral complexes were separated with fractional method of particle size and density from steppe soils, one degraded and another recovering. Then humus of different combined forms was extracted from these complexes, and humus content, distribution and composition were analyzed respectively. Results showed that humus of complexes was mainly composed of loosely and tightly combined form, and most of them were distributed in clay and silt complexes. Increases of soil humus in process of grassland restoration firstly resulted from loosely combined humus in clay and silt complexes, and secondly from stablely form. Meanwhile, increases of loosely combined humus mainly resulted from HA composition and stablely humus mainly from FA.