钱江源国家公园不同景观土壤有机碳库和蓄水性能研究

Soil Organic Carbon Pool and Water Storage Performance of Different Landscapes in Qianjiangyu⁃an National Park

为了解钱江源国家公园不同土地利用景观区生态功能的差异,选择林地、茶园、水田和旱地等4类土地利用景观,分别采集了代表性表层和土壤剖面分层土样,分析了土壤有机质组分、酸碱度、主要养分元素及渗透性和蓄水性。结果表明,土壤有机质含量由表层向下呈下降趋势,土壤有机质含量、贮量和活性有机质占有机质的比例均是林地>茶园>水田>旱地,土壤C/N比为林地>茶园>水田、旱地;土壤pH值为水田>旱地>林地>茶园;土壤有效磷和速效钾含量为茶园>水田、旱地>林地。林地表层土壤具有较低的容重,其透水性和蓄水能力明显高于茶园和旱地,并具有较高的阳离子交换量和水稳定性团聚体数量。研究认为,从土壤固碳与保水2个方面考虑,钱江源国家公园内林地的生态功能明显强于其他景观用地,旱地的生态功能最弱。因此,加强林地建设和逐渐减小旱地面积有助于强化园区生态功能。

To understand the differences of soil ecological functions in different landscapes of the Qianjiangyuan Na⁃tional Park,four types of land-uses,including woodland,tea garden,paddy field and upland,were selected in the Park.Both representative surface soil and profile horizon soil samples were collected from each of land-uses for char⁃acterizing organic matter,pH,main nutrient elements,water permeability and water storage capacity.The results showed that the content of soil organic matter decreased from the surface to the bottom,content and storage of organic matter,and the proportions of active organic matter in total organic matter decreased in the order of woodland>tea garden>paddy field>upland.C/N ratio in the soils decreased in sequence of woodland>tea garden>paddy field and upland.Soil pH decreased in the order of paddy field>upland>woodland>tea garden.Soil available phospho⁃rus and available potassium increased in the order of woodland<upland<paddy field<tea garden.The surface soil in woodland had lower bulk density,and higher water permeability,storage capacity,cation exchange capacity and content of water stable aggregates than those in tea garden and upland.From the two aspects of soil carbon sequestra⁃tion and water conservation,the results indicated that the ecological function of woodland in the Park was obviously stronger than that of other land-uses,while the ecological function of upland was the weakest.Therefore,strengthen⁃ing the construction of woodland and gradually reducing the area of upland will help to enhance the ecological func⁃tion of the park.