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水稻生长影响土壤有机质在土壤及其各组分中的分布,是关系土壤有机质储量的重要因子.为量化水稻光合同化碳在土壤不同粒径和密度组分中的分布,进而为水稻土有机质积累持续机制与固碳潜力研究提供数据支撑,应用14C连续标记示踪技术,以当地主栽水稻品种“中优169”为供试作物,分别选取亚热带区4种典型稻田土壤,通过土壤有机质物理分组方法探讨了水稻根际输入的光合碳在土壤物理组分(粒径、密度)中的含量和分配特征.结果表明,水稻标记种植80 d后,250～2 000μm粒径的SOC14含量范围为118.23～309.94 mg.kg-1,SOC14/SOC的比例范围为0.52%～1.55%,均大于20～250μm、<20μm这2个粒径的SOC14含量和SOC14/SOC的比例,250～2 000μm、20～250μm这2个粒径的轻组组分的SOC14含量均显著大于相应的重组组分的SOC14含量,说明稻田生态系统通过水稻的根际沉积作用将有机碳(水稻光合同化碳)主要固定在大粒径的轻组组分中,从而提高了土壤有机碳含量.相关分析表明,250～2 000μm粒径与其轻、重组组分、<20μm粒径、20～250μm粒径的SOC14含量之间均呈显著性正相关,而<20μm、20～250μm粒径的轻组组分的SOC14含量之间呈极显著性负相关.
The effect of rice growth on the distribution of soil organic matter in soils and its components is an important factor related to soil organic matter reserves.In order to quantify the distribution of photosynthetic carbon in different particle size and density components of soils, Accumulation of persistent mechanism and carbon sequestration potential of the study provide data to support the application of 14C continuous labeling tracer technology to the local main rice varieties “Zhongyou 169 ” as the test crop, were selected subtropical four typical paddy soil, soil The organic matter partitioning method was used to investigate the content and distribution of photosynthetic carbon (C 2 O 4) input in rhizosphere of rice in soil physical components (particle size and density). The results showed that the SOC14 content of 250 ~ 2 000 μm The range of SOC14 content and SOC14 / SOC ratio of the two particle sizes is 118.23 ~ 309.94 mg.kg-1, the ratio of SOC14 / SOC is 0.52% ~ 1.55%, all of them are larger than 20 ~ 250μm, 000μm and 20 ~ 250μm, respectively, were significantly higher than SOC14 content of the corresponding recombinant components, indicating that the paddy field ecosystem through the rhizosphere deposition of rice organic carbon (photosynthetic carbon ) The content of organic carbon in soil increased with the increase of soil organic carbon content.The results of correlation analysis showed that the particle size of 250-2000μm and its light and recombinant components, particle size of <20μm, SOC14 of particle size of 20-250μm There was a significant positive correlation between the content of SOC14 and the content of SOC14 in the light fractions of <20μm and 20 ~ 250μm.