Key Laboratory of Agro-ecological Processes in the Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China.
J Sci Food Agric. 2012 Mar 30;92(5):1031-7. doi: 10.1002/jsfa.4645. Epub 2011 Oct 12.
Microbial activities involved in the dynamics of organic matter determine the potential for organic carbon (C) accumulation in soil. To understand this for paddy soil, an incubation experiment (25 °C, 45% water-holding capacity) was established using (14)C-labelled glucose and rice straw (500 µg C g(-1) soil) as substrates; an adjacent upland soil was used for comparison.
The amount of microbial biomass in the paddy soil was approximately 6 times larger and its turnover rate was 1.5-3 times faster than in the upland soil. These proportions of (14)C-labelled glucose and rice straw mineralized in the paddy soil were about 3% smaller (P < 0.01) than those in the upland soil. Also, there was no significant priming effect of fresh substrate additions on the mineralization of native organic C in the paddy soil, while the priming effect was significant in the upland soil.
Although the paddy soil contains a large amount of microbial biomass, which is also very active, the mineralization of fresh substrates is significantly restricted in this soil, along with a small priming effect. This favours the accumulation of organic C in paddy soils.
参与有机质动态变化的微生物活性决定了土壤中有机碳（C）积累的潜力。为了了解稻田土壤的情况，我们使用（14）C 标记的葡萄糖和稻草（500µg C g（-1）土壤）作为底物进行了一项培养实验（25°C，45%持水能力）；同时使用相邻的旱地土壤进行了对比。
稻田土壤中的微生物生物量大约是旱地土壤的 6 倍，其周转率比旱地土壤快 1.5-3 倍。（14）C 标记的葡萄糖和稻草在稻田土壤中的矿化比例比旱地土壤小约 3%（P<0.01）。此外，新鲜底物的添加对稻田土壤中天然有机 C 的矿化没有显著的激发效应，而在旱地土壤中则存在显著的激发效应。
尽管稻田土壤中含有大量的微生物生物量，而且这些微生物也非常活跃，但新鲜底物的矿化在这种土壤中受到了明显的限制，同时激发效应也较小。这有利于有机 C 在稻田土壤中的积累。
