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为研究区域景观尺度土地利用方式变化对稻田土壤有机碳储量的影响,利用野外实地采样中1264个土壤样点有机碳含量的调查,采用遥感和GIS手段,分析红壤丘陵景观1933-2005年的土地利用变化引起的稻田表层土壤有机碳储量的动态变化。结果表明:研究区稻田与林地、茶园呈双向演替机制,以林地转变为稻田为最主要的土地利用变化方式,集中在高程50m-150 m内。稻田表层土壤有机碳含量为14.3 g/kg,显著大于林地(13.0 g/kg)和茶园(9.5 g/kg)(p<0.01);且稻田土壤有机碳的变异系数仅为26.0%,明显低于林地(55.5%)和茶园(50.9%)。1933-2005年间,由稻田转变为其他利用方式(主要为林地和茶园)的面积为1233.53 hm2,共损失碳10015 t,而由其他利用方式转变为稻田的面积为1598.90 hm2,共增加碳15372 t。总体而言,1933-2005年间稻田土壤表层碳库呈增加的趋势,表现为碳增汇;土壤有机碳储量在高程50m-150 m内受土地利用变化影响的方向和程度最为显著。因此,保护和增加50m-150 m高程内的稻田面积对于提升亚热带红壤丘陵区的固碳潜力具有重要的意义。
In order to study the impact of land use change on soil organic carbon storage in the regional landscape scale, a survey of 1264 soil organic carbon samples in the field sampling was conducted. Using remote sensing and GIS, the landscape of the hilly red soil in 1933-2005 Dynamic Changes of Soil Organic Carbon Storage in Paddy Fields Induced by Variation. The results showed that the paddy field, the woodland and the tea plantation in the study area presented a bi-directional succession mechanism. The main land-use change was the transformation from forestland to paddy field, and the concentration was in the range of 50m-150m. The content of organic carbon in surface soil of paddy field was 14.3 g / kg, significantly higher than that of forest (13.0 g / kg) and tea plantation (9.5 g / kg) (p <0.01), and the coefficient of variation of soil organic carbon was only 26.0% Woodland (55.5%) and Tea Garden (50.9%). Between 1933 and 2005, the area converted from rice fields to other uses (mainly woodland and tea plantation) was 1233.53 hm2, with a total loss of 10,001 t of carbon and 1598.90 hm2 of land converted from other uses to paddy fields, with a total increase of 15,372 t of carbon . In general, the surface carbon pool of paddy soil increased from 1933 to 2005, which was characterized by carbon sinks. The direction and degree of soil organic carbon storage affected by land-use change within the range of 50m-150m elevation were the most significant. Therefore, protecting and increasing the paddy field area within the elevation range of 50m-150m is of great significance for enhancing the carbon sequestration potential in subtropical red soil hilly areas.