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土壤有机碳在陆地生态系统碳循环中起着举足轻重的作用。针对农田区域内典型县域尺度有机碳储量及其空间格局特征的研究,可以为区域农田土壤固碳提供参考,为研究我国土壤有机碳储量提供基础数据支持。基于2012年农田土壤有机碳分析调查数据,结合GIS和GPS技术对川中丘陵区盐亭县土壤有机碳密度和储量及空间格局进行了估算和分析。结果表明:其主要土壤类型的0~20cm耕层土壤有机碳密度为1.11~4.26kg/m2,平均值为2.66kg/m2,水田和旱地耕层土壤有机碳密度分别为3.45和2.34kg/m2,均低于全国平均值;全县20cm深度土壤有机碳总储量2.50×109 kg C,紫色土类土壤有机碳储量最大,为1.53×109kg C,水稻土次之,有机碳储量0.93×109kg C,两者占据了农田土壤有机碳储量约98%,冲积土和黄壤土类由于面积小,有机碳储量也最低。各土壤类型有机碳储量丰度指数(RI)值都较低,碳存储能力处于中下水平。在县域农田尺度,有机碳空间格局与气候差异、植被类型关系不大,土壤类型空间差异和地形差异是有机碳空间格局形成的主要原因。
Soil organic carbon plays a decisive role in the carbon cycle of terrestrial ecosystems. The research on the typical county-scale organic carbon storage and its spatial pattern in the farmland region can provide reference for soil carbon sequestration in the farmland, and provide basic data for the study of soil organic carbon storage in China. Based on the survey data of farmland soil organic carbon in 2012 and the combination of GIS and GPS technology, the soil organic carbon density and the spatial pattern of Yanting County in the central Sichuan hilly region were estimated and analyzed. The results showed that the soil organic carbon density of 0-20 cm soil layer of main soil types was 1.11 ~ 4.26 kg / m2, the average was 2.66 kg / m2, and the soil organic carbon density of paddy field and dry land was 3.45 and 2.34 kg / m2 , All lower than the national average. The total soil organic carbon storage at the depth of 20cm in the county was 2.50 × 109 kg C, and the purple soil had the largest organic carbon storage of 1.53 × 109kg C, followed by paddy soil with 0.93 × 109kg C , Both of which account for about 98% of the soil organic carbon storage in farmland. Due to the small area and the lowest organic carbon storage in alluvial and yellow loamy soil, The organic carbon storage abundance index (RI) values of all soil types were lower, and the carbon storage capacity was at the middle and lower levels. In farmland scale of county, the spatial pattern of organic carbon has little to do with climate difference and vegetation type. The main reason for the formation of organic carbon spatial pattern is the difference of soil type and topography.