纳帕海不同土地利用方式下土壤有机碳分布特征

The Distribution Characteristics of Soil Organic Carbon under Different Land Uses Patterns in Napahai

[目的]探讨纳帕海区域土壤有机碳(SOC)在不同土地利用方式下的剖面分布特征及其与土壤含水量、容重的相关关系,为该区域合理高效利用土地资源提供科学依据。[方法]对猪拱地、农田、灌丛和森林4种土地利用类型的SOC分布特征进行研究。[结果]0~50 cm土层深度内,SOC含量由高到低依次为农田(26.43 g/kg)、猪拱地(20.95 g/kg)、灌丛(20.16 g/kg)、森林(17.25 g/kg);猪拱地、农田、灌丛和森林均为0~10 cm土层SOC含量最高,是主要的碳储层,分别占0~50 cm土层的37.42%、28.07%、49.81%和30.10%,随土壤深度的加深,SOC含量呈减少趋势;SOC密度与SOC储量呈基本一致的变化趋势;各样地表层SOC与土壤含水量呈显著正相关(R^2=0.50,P<0.05),与土壤容重呈极显著负相关(R^2=0.60,P<0.01)。[结论]不同土地利用类型其SOC含量在垂直方向上的分布不同,湿地的退化会不同程度地导致SOC流失,表层SOC含量很大程度上受土壤含水量和土壤容重的制约。

[ Objective ] To study the profile distribution characteristics of soil organic carbon （SOC） under different land use patterns and its correlation with soil water content and bulk density in Napahai plateau wetland in order to provide scientific basis for the rational and efficient use of land resource in the region. [Method]The pig arched meadow, farmland, shrub and forest were selected in this area and the study was carried out. [ Result] In 0 -50 cm soil depth, soil organic carbon content from high to low was farmland （26.43 g/kg）, pig arched meadow （20.95 g/kg）, shrub （20.16 g/kg） , forest （17.25 g/kg） in Napahai plateau wetland area. SOC content was the highest at 0 -10 cm soil layer and which was the main SOC reservoir accounted for 37.42%, 28.07%, 49.81% and 30.10% of 0 - 50 cm soil depth, and the SOC content decreased with soil depth enhance. The SOC density and SOC reserves showed a consistent trend. According to the regression equa- tion, the soil water content was positively correlated with SOC（ R^2 = 0. 50, P 〈 0.05 ）and the soil bulk density was negatively correlated with SOC （ R^2 = 0. 60 ,P 〈 0.01 ）, and they all reached a significant level in the soil surface layer （P 〈 0.05 ）. [ Conclusion ] Different land use patterns have different storage capacity for SOC in vertical direction, and the degradation of wetland will lead to the loss of SOC in varying degrees. The content of SOC in the surface is largely affected by soil water content and soil bulk density.