三江平原草甸湿地土壤有机碳矿化对C/N的响应

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。

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

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 C₀ and C₀/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.