长期植稻年限序列水稻土团聚体有机碳分布特征

通过开展有机质物理分组试验,研究了杭州湾南岸不同植稻年限序列水稻土有机碳含量的粒级分布变化特征.结果表明: 各植稻年限耕层水稻土中,土壤团聚体主要分布在微团聚体(<0.25 mm)中,其中大微团聚体(0.053～0.25 mm)随着植稻年限的增加而减少；在微团聚体(0.053~0.25 mm,<0.053 mm)中,有机碳含量随着植稻年限的增加而增加,在0.053～2 mm粒径范围内,各粒级有机碳占总有机碳比例随着粒级的减小而增加,有机碳主要集中在大微团聚体(0.053～0.25 mm)中；随着种植年限的增加,颗粒有机碳含量减少.栽培年限长的水稻土比栽培年限短的水稻土碳封存量大,早期开垦的水稻土仍有很大的固碳潜力.

Distribution characteristics of aggregates organic carbon in a paddy soil chronosequence

By the method of physical fractionation of organic matter, this paper studied the distribution characteristics of organic carbon in different particle size aggregates in a paddy soil chronosequence on the south bank of Hangzhou Bay, East China. In the plow layers of the paddy soil chronosequence, micro-aggregates (<0.25 mm) dominated, and the proportion of large micro-aggregates (0.053-0.25 mm) decreased with increasing rice cultivation year. In the micro-aggregates (<0.053 mm and 0.053-0.25 mm), the organic carbon content increased with increasing rice cultivation time; and in the aggregates (0.053-2 mm), the ratio of the organic carbon in different particle size fractions to the bulk soil organic carbon increased with decreasing particle size, and the organic carbon mainly distributed in large micro-aggregates (0.053-0.25 mm). With increasing rice cultivation time, soil particulate organic carbon decreased, indicating that the paddy soil with a longer rice cultivation history had a stronger capability of carbon sequestration than the soil with a shorter rice cultivation history, and the early cultivated paddy soil still had great potential for carbon sequestration.