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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,在密闭系统模拟研究水稻根际输入光合碳对土壤有机碳(SOC)及其组分的影响.结果表明,标记种植80 d后,水稻地上部和地下部的累积的总碳量范围分别为1.86～5.60 g.pot-1和0.46～0.78 g.pot-1.种植水稻后供试土壤的14C-SOC含量范围为114.3～348.2 mg.kg-1,而14C-DOC、14C-MBC含量范围为4.05～8.65 mg.kg-1、12.5～37.6 mg.kg-1.水稻生长期间内,不同土壤条件下,土壤14C-SOC与14C-水稻碳量的比率范围为5.09%～6.62%,这说明尽管不同土壤的光合生产能力不同,但根际沉积效率相似.土壤可溶解性有机碳(DOC)、微生物量碳(MBC)和SOC的更新率分别为6.72%～14.64%、1.70%～7.67%和0.73%～1.99%.而且,水稻光合碳的分配和转化对土壤活性碳组分的DOC、MBC含量变化影响较大,而对土壤有机碳影响较小.本研究进一步量化了水稻生长期间光合碳对土壤有机碳库各组分(SOC、DOC和MBC)的贡献,为水稻土有机质积累持续机制与固碳潜力研究提供了数据支撑.
Using 14C continuous marker tracing technique, four typical paddy soils of subtropical zone were selected from the main cultivated rice variety “Zhongyou 169” as tested crop, and the effects of photosynthetic carbon on rice rhizosphere were studied in a closed system. (SOC) and its components were studied.The results showed that after 80 d of planting, the accumulated total carbon in shoots and underground parts ranged from 1.86 to 5.60 g.pot-1 and from 0.46 to 0.78 g.pot -1. The 14C-SOC content of paddy soils tested ranged from 114.3 to 348.2 mg.kg-1, while the 14C-DOC and 14C-MBC ranged from 4.05 to 8.65 mg.kg-1 and 12.5-37.6 mg. kg-1. The ratio of soil 14C-SOC to 14C-rice under different soil conditions during the growth of rice ranged from 5.09% to 6.62%, indicating that although the photosynthetic capacity of different soils is different, the rhizosphere sedimentation efficiency .The rates of DOC, MBC and SOC renewal ranged from 6.72% to 14.64%, 1.70% to 7.67% and 0.73% to 1.99%, respectively.Moreover, the distribution of photosynthetic carbon And transformation had a significant effect on the contents of DOC and MBC in soil active carbon, but had little effect on soil organic carbon.This study further The contribution of carbon during photosynthesis in rice grown on soil organic carbon pool of components (SOC, DOC and MBC) of paddy soil organic matter accumulation potential of carbon sequestration and sustained mechanism provides data support.