环渤海地区土壤有机碳库及其空间分布格局的研究

土壤碳库的研究和管理以及土地利用变化对土壤碳库的影响已成为全球变化研究中的核心内容．本文利用第2次土壤普查时环渤海地区1374个土壤剖面资料，对该地区土壤有机碳库进行了估算，结果表明，整个环渤海地区1m深的土壤有机碳库为2．1PgC．进一步分析该区域各土壤类型的有机碳库发现，棕壤的有机碳库最大，占该区域总有机碳库的55．6％，其次为潮土，占26．9％，风沙土和暗棕壤的土壤有机碳库则很小，仅占0．1％以下．对不同土壤类型的碳密度比较发现，沼泽土的碳密度最高，为22．9kgC·m^-2，其次是暗棕壤，为16．04kgC·m^-2；而风沙土的碳密度最低，为2．88kgC·m^-2，再次是盐土，为6．0kgC·m^-2．可见土地风沙化和盐碱化将极大地降低土壤的有机碳．此外，该地区表层土壤中的碳储量为673．30TgC，即约占总碳储量三分之一的土壤碳易受人类活动的影响．该地区土壤有机碳的水平分布主要为沿海地区、平原地区、西北部地区和山地丘陵区4个区域，其碳密度由大到小依次为山地丘陵区(森林)>西北部地区(农牧区)>平原地区(农业)>沿海地区(裸地)．其分布规律不仅在一定程度上体现了气候和地形等因素的作用，而且充分反映了不同人类活动强度对土壤有机碳的影响．因此，加强该区域土地的保护和管理对于维护土壤有机碳和土地的持续利用极其重要．

Soil organic carbon pool and its spatial distribution pattern in the Circum Bohai Region

The research and management of soil carbon pool and the effect of land-use on it are the key project of study on global change. In this paper, the data of 1 374 soil profiles in the Circum Bohai Region were used to estimate the soil organic carbon (SOC) pool of this region. The results showed that in this region, the total soil organic carbon pool in 1m depth was 2.1 Pg C, and the biggest SOC pool was brown soil, occupying 55.6 % of the total SOC. The second one was moisture soil, accounted for 26. 9 % . The SOC pools of aeolian sandy soil and dark brown soil were very small, only about 0.1% of the total. However, the soil organic carbon density (OCD) of boggy soil was the biggest (22.90 kg C.m-2), the second was dark brown soil (16.04 kg C.m2), and the lowest were aeolian sandy soil (2.88 kg C.m-2) and solonchak (6.0 kg C.m-2), implying that desertification and salinalization could reduce soil organic carbon. Moreover, the results also suggested that the topsoil held 673. 30 Tg C. It meant that there was about one-third of the total SOC could be easy to be disturbed. According to the OCD at its level distribution gradient, it could be divided into four regions, i. e., coastal region, plain region, northwestern region, and hilly region. The order of OCD from high to low was hilly region, northwestern region, plain region, and coastal region. This regulation reflected not only the role of climate and landform, but also the effect of human activity intensification on SOC. Therefore, it was very important to protect and manage the land in this region well for the SOC maintenance and the sustainable land use.