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通过实地研究主要位于宜兴市域的区域乡村景观代表性样方,评价并阐明了人口密集的长江下游平原区乡村景观的结构,土地管理与土壤有机碳储量的关系。景观绘图是基于1m分辨率的IKONOS影像并采用生态立地分类及绘图标准,通过直接解译和实地检验对边界清晰的均质景观缀块进行分类和绘图;依据区域权重分层取样设计方法,在生态立地斑块中随机设定取样点进行土壤和淤泥取样;利用区域权重系数进行区域土地利用/覆被和土壤有机碳储量评价计算。结果表明:在2.13×106hm2的长江下游平原区乡村景观面积范围内,0~30cm土壤有机碳储量为76.97Tg。该区域土地利用/覆被的主要类型为水田,水产养殖,非渗漏性建筑用地,旱地1年生作物和水浇地多年生作物,这5种类型的面积百分数和土壤有机碳储量百分数分别为83%和85%。其中平原稻田面积为0.89×106hm2,占总面积的42%;其0~30cm土壤有机碳储量高达36.60Tg,占总储量的48%。通过区域分层取样和小尺度景观斑块的区域权重推绎分析,揭示了人口密集的乡村景观中土地利用/覆被方式对当地和区域土壤有机碳的影响模式。这种在小尺度下对土地管理调查,土壤有机碳和其它生态特征研究的方法明显优于传统的基于30~1000m分辨率遥感影像的土地覆被研究和基于土壤类型的区域土壤有机碳储量评价方法。
Through the field study of representative rural quadrats in Yixing City, this paper evaluates and clarifies the relationship between the structure of rural landscape and the management of soil organic carbon in the densely populated area of the lower reaches of the Yangtze River. Landscape mapping is based on IKONOS image with 1m resolution and adopts eco-site classification and drawing standard to classify and draw homogenous landscape patch with clear boundary through direct interpretation and field inspection. According to the hierarchical sampling design method based on region weight, Samples of soil and silt were randomly set in sampling plots of ecological sites and regional land use / cover and soil organic carbon storage were evaluated using regional weight coefficients. The results showed that within the area of 2.13 × 106hm2 in the plain area of the lower reaches of the Yangtze River, the soil organic carbon storage at 0 ~ 30cm was 76.97Tg. The main types of land use / cover in the region are paddy fields, aquaculture, non-leakage construction land, dryland annual crops and irrigated perennial crops. The percentages of these five types of area and soil organic carbon stocks are 83 % And 85%. The plain paddy field area is 0.89 × 106hm2, accounting for 42% of the total area. The organic carbon storage area of 0-30cm is 36.60Tg, accounting for 48% of the total reserves. Through the regional stratified sampling and regional weight deduction analysis of small-scale landscape patches, the impact model of land use / cover on the local and regional soil organic carbon in densely populated rural landscapes was revealed. This method of small-scale survey of land management, soil organic carbon and other ecological characteristics is obviously superior to the traditional land cover research based on remote sensing images of 30 ~ 1000m resolution and evaluation of regional soil organic carbon storage based on soil types method.