地形和土地利用对黄土丘陵沟壑区小流域土壤无机碳分布的影响

地形和土地利用方式对土壤无机碳(SIC)的空间分布和碳汇效应有重要影响。以黄土高原丘陵沟壑区纸坊沟小流域为对象,研究土地利用、地形对0-200cm土层内SIC空间分布的影响。结果表明,地形对纸坊沟流域SIC空间分布呈极显著影响(P<0.01),表现为峁顶(15.32g/kg)>坡地(14.45g/kg)>沟底(12.27g/kg)的变化趋势;土地利用方式影响该流域SIC分布,其含量表现为灌木地>草地>林地>农地,其中灌木地极显著高于林地、草地和农地,林地和草地极显著高于农地,而林地与草地无显著差异;地形与土地利用交互作用极显著影响SIC空间分布(P<0.01)。相关结果可为黄土高原土壤碳库提供基础数据,有助于明确黄土高原在中国陆地碳循环中的作用。

Effects of Topography and Land Use on Spatial Distribution of Soil Inorganic Carbon in a Small Watershed of the Loess Hilly-gully Region

It is significant to accurately assess regional spatial distribution characteristics and influencing factors of soil inorganic carbon and to study effects of land use and topographies on spatial distribution of soil inorganic carbon.Taking Zhifanggou small watershed,which is situated in loess hilly-gully region,as an object,influences of land use and topographic on the distribution of inorganic carbon on 0-200 cm soil layer were studied.Results showed that the terrain had a significant influence on the spatial distribution of soil inorganic carbon on Zhifanggou small watershed,and ranged as: Table land(15.32 g/kg) >slope land(14.45 g/kg) >gully land(12.27 g/kg).There were differences in the distribution of soil inorganic carbon under different land use.Soil inorganic carbon content in shrub land were significantly higher than those in wood land,grassland and farmland,wood land and grassland significantly higher than those in farmland.But there were no significant difference between wood land and grassland,and soil inorganic carbon content under different land use could be ordered as follows: Shrub land >grassland >woodland >farmland;interaction of topographic position and land use significantly affected the spatial distribution of soil inorganic carbon(P<0.01).The result can provide basic information for soil carbon pool of the Loess Plateau,it is helpful to know that the Loess Plateau which is important to carbon cycle of terrestrial ecosystems of China.