上海土壤有机碳储量及其空间分布特征

RESERVES AND SPATIAL DISTRIBUTION CHARACTERISTICS OF SOIL ORGANIC CARBON IN SHANGHAI CITY

区域土壤碳库的估算不仅是陆地土壤碳循环研究的重要内容,同时也可为国家尺度的土壤碳库的估算提供更多的数据支持。利用上海第二次土壤普查资料,结合GIS技术对上海土壤有机碳储量、碳密度及其空间分布格局展开研究,结果表明,上海地区0～100cm深度的土壤有机碳总储量为5.76×107 t,占全国的0.062 6%,0～100cm的平均土壤有机碳密度为10.55kg/m2,高于全国平均值,反映出上海土壤具有较高的碳蓄积能力。各类土壤中,水稻土的土壤碳储量最大,其次是灰潮土和滨海盐土,而黄棕壤由于面积狭小,所以土壤碳储量最小。各类土壤0～100cm土壤有机碳密度的大小顺序依次为水稻土>灰潮土>黄棕壤>滨海盐土。从空间分布格局来看,上海土壤碳密度呈现为西高东低,在局部范围内还表现出高低相间,错综复杂的局面,这种分布规律在一定程度上体现了地形、微地貌、母质、土地利用方式等因素的影响。而快速的城市化引起的土地利用变化造成了土壤碳库的净碳损失量为392.44万t,相当于2000年化石燃料产生的碳排放的9.86%,这表明在经济和城市快速发展地区,土地利用变化已经成为影响土壤碳库的重要驱动力。

Estimation on soil carbon pool in regional scale is an important project in research on soil carbon cycling of terrestrial ecosystem,which can supply sufficient data for evaluating soil carbon storage in national scale.Combined with GIS,this paper studied the storage of soil organic carbon,the SOC（soil organic carbon）density of different soil types and its distribution in Shanghai City,based on the second soil survey of Shanghai City.The result shows that the total soil organic carbon storage at 100 cm depth of Shanghai City is 5.76×107 t,accounting for 0.062 6% of that of the country,and the mean of SOC density is 10.55 kg/m2,higher than that of the country,which shows higher carbon sequestration in Shanghai City.In different soil types,paddy soil has the most storage of SOC,followed by calcareous alluvial soil and seashore saline soil.Yellow brown soil has the least storage of SOC because of its limited area.As for the SOC density of different soil types,its turn is as follows：paddy soilcalcareous alluvial soilyellow brown soilseashore saline.The spatial distribution of SOC density in Shanghai City is that the density of the west is higher than of the east,and in local range,the situation becomes complicated,which shows the influence of the terrain,microtopography,parent material,land use and land-cover chang LUCC,et al.The net loss of SOC is 3.924 4 Mt,due to the LUCC caused by rapid urbanization,corresponding to 9.86% of carbon emitted by fossil fuel in 2000,which indicates LUCC has become the major driving force influencing the SOC pool in rapidly urbanized region.