小流域生态建设对土壤团聚体及其有机碳影响研究

Effects of Ecological Construction on Soil Aggregation and Organic Carbon in A Small Watershed

以黄土高原王茂沟典型流域5种不同生态建设方式土壤为研究对象,探讨不同的生态建设条件下,坡耕地转变为林地、草地、灌木地及梯田对0～60cm土层土壤团聚体稳定性及其有机碳含量的影响.结果表明:对坡耕地实施水土保持林草、工程措施后,大团聚体破碎化降低,土壤结构稳定性增加,微团聚体向中间团聚体和大团聚体转化,土壤结构趋于改善.坡耕地和灌木土壤有机碳主要分布在微团聚体内,草地有机碳主要分布在大团聚体内,梯田大团聚体有机碳储量最低,林地团聚体有机碳储量差异不显著.对坡耕地进行生态建设恢复,可以有效促进0～20cm土层土壤团聚体有机碳的积累和保护,有助于土壤有机碳的恢复和截存.该研究可为合理规划区域生态建设和促进土壤碳库的管理提供科学依据.

Five ecological construction patterns in Wangmaogou,a typical watershed on theLoess Plateau,were selected as research objects.The soil aggregate stability andaggregate-associated organic carbon content in 0~60 cm soil layer were evaluated aftersloped farmland transformed to forestland,grassland,shrub land and terraced field.Theresults showed that implementation tree-grass planting measures and engineeringmeasures decreased the fragmentation of the large aggregates,increasedthe stability ofsoil structure,facilitated the micro-aggregate transformed to middle aggregate and largeaggregate,and improved the soil structure.Soil organic carbon in slopedfarmland,shrublands and grasslandswere mainly distributed in the micro-aggregates and large-aggregates,respectively.The terraced field had the lowest organic carbon storage inlarge-aggregates.And the soil organic carbon storage in different soil aggregates had nosignificant difference in woodland.Conducted ecological construction on sloped farmlandcould effectively improved the accumulation and protection of organic carbon in soilaggregates in 0~20 cm soil layer.The present study could provide scientific basis forrational planning theregional ecological construction and management the soil carbonstorage.