南长山岛不同土地利用方式下的土壤有机碳密度

Soil organic carbon density under different land use types on the Nanchangshan Island of Miaodao Archipelago

土壤有机碳库是陆地生态系统中重要的碳库之一,以往对海岛生态系统土壤有机碳储量估算及其影响因素的研究较少.因此,本研究在南长山岛实测了不同土地利用方式下表层土壤的有机碳密度,比较了相互之间的差别,分析了与土壤理化性质的相关性.结果表明,南长山岛不同土地利用方式土壤有机碳密度差异显著(p<0.01),表现为:针阔混交林>刺槐>黑松>侧柏>农田>水库沿岸草地>果园;森林土壤有机碳密度高于其他类型土壤.森林土壤有机碳密度与坡度(r=-0.459,p=0.085)、海拔相关性不显著.在土壤理化性质中,土壤全氮(r=0.763,p<0.01)、有机质(r=0.833,p<0.01)含量与森林土壤有机碳密度呈显著正相关.

Soil organic carbon( SOC) library is one of important carbon sources in the terrestrial ecosystem. However,the comprehensive estimation on total SOC reserves and their influencing factors in the island ecosystem,especially under different land-use types,are limited. In this paper,the SOC densities of topsoil in four land-use types,including forest,farmland,orchard and grassland( reservoir area),on the Nanchangshan island of Miaodao Archipelago in Shandong Province were investigated. The relationships of SOC density with physical and chemical properties of soil were also examined. The results indicated that the SOC density in the topsoil in different land-use types decreased in the order( p<0. 01) : deciduous-conifer mixed forest>R. Pseudoacacia forest>P. Thunbergii forest>P. Orientalis forest>farmland>grassland>orchard. The SOC density of forest was higher than that of the others. Pearson correlation analysis showed that there were no significant correlation between forest SOC density and slope( r =- 0. 459,p = 0. 085) and elevation. The SOC density of forest was influenced by soil physical-chemical properties. The SOC density of forest was significantly positively correlated with total nitrogen( r = 0. 763,p<0. 01) and organic matter( r = 0. 833,p<0. 01).