三江平原草甸湿地土壤有机碳矿化对C/N的响应

Effects of Amendment C/N Ratio on Soil Organic Carbon Mineralization of Meadow Marshes in Sanjiang Plain

模拟研究了三江平原典型草甸小叶章湿地及人工林地土壤有机碳（SOC）矿化在4种C／N（Ⅰ：9—10，Ⅱ：11-12，Ⅲ：13—16，Ⅳ：16—22）处理下的变化特征，分析了SOC矿化对C／N的响应。结果表明：在36天的培养期内，高C／N处理下两种土壤的SOC累积矿化量分别是低C／N时的2．78和2．68倍，两种土壤SOC矿化量对C／N变化的响应不存在显著差异；不同C／N处理下，两种土壤SOC的矿化速率均在前期（0—4天）较高，随着培养时间的延长逐渐降低，并趋于稳定；一级动力学方程能较好的描述两种土壤的SOC矿化动态，其C0和C0／SOC值均随C／N的增加而增加；回归分析表明，试验C／N（9—22）范围内湿草甸土和林地土的SOC累积矿化量及矿化速率分别与C／N呈显著的线性和二次曲线关系，C／N是影响湿地土壤有机碳富集程度的关键因素。

An incubation expericment with typical Deyeuxia angustifolia meadow soil and artificial forest soil in the Sanjiang plain was conducted under different soil C/N （Ⅰ：9-10,Ⅱ：11-12,Ⅲ：13-16,Ⅳ：16-22） to examine the responses of soil organic carbon （SOC） mineralization to C/N changes. The result showed that during the period of 36d incubation, the SOC accumulative losses of two kinds of soils under high C/N treatment were about 2.78 and 2.68 times as much as that under low C/N, respectively. SOC mineralization rates for both the two kinds of soils were higher in the first 4 days of incubation, and became stable as the time prolonged. The dynamics of SOC mineralization of two kinds of soil preferably followed the first-order kinetics, and the CO and Co/ SOC values increased exponentially with the increasing of C/N. The regression analysis also found that there were significant linear or conic relationships between the accumulative loss and mineralization rate of SOC and C/ N, which explained that C/N was the key factor in affecting the sequestration of SOC in wetland.