【摘要】 为探讨不同地力玉米田土壤有机碳矿化特征,通过为期196 d的土壤有机碳矿化培养试验,对高、中、低3种不同地力玉米田0～20 cm和20～40 cm土层土壤进行了研究。结果表明:不同地力玉米田土壤有机碳矿化速率随时间的变化呈现相同的变化趋势,即随培养时间延长,呈现先高后低的变化趋势,最后趋于平稳;但随地力等级的降低,土壤有机碳矿化速率逐渐减小。培养结束时,不同地力玉米田0～20 cm和20～40 cm土层土壤有机碳累积矿化量之间均存在显著性差异(P<0.05);低地力土壤有机碳稳定性最差,固存量最小。同一地力,20～40 cm土层土壤有机碳矿化速率和累积矿化量较0～20 cm显著降低(P<0.05),表层土壤稳定性较差,不利于土壤有机碳固定。伴随土壤有机碳矿化过程,土壤微生物生物量碳(MBC)和土壤可溶性有机碳(DOC)含量均较初始含量显著降低(P<0.05);土壤有机碳潜在矿化势(Cp)与土壤有机碳、全氮、铵态氮、硝态氮、MBC和DOC均呈极显著正相关。土壤有机碳矿化是陆地生态系统碳循环的重要过程,且当地力等级变化时,各土层土壤有机碳的稳定性均受到不同程度的影响。更多还原

【Abstract】 In order to explore the mineralization characteristics of soil organic carbon, we carried out soil organic carbon mineralization culture experiments lasting 196 days using the soil from 0～20 cm and 20～40 cm depths with different fertility(high, medium, and low soil fertility). The results showed that the soil organic carbon mineralization rate varied over time and exhibited a consistent trend in maize fields with different soil fertility(the mineralization rate first increased, then decreased, and finally stabilized). With the decrease in soil fertility,the mineralization rate of soil organic carbon gradually decreased. At the end of the culture experiment, there were significant differences in the cumulative mineralization amount of soil organic carbon between the 0～20 cm and 20～40 cm deep soils with the same soil fertility level(P<0.05). Compared to the other soil fertility levels, the soil organic carbon in the low fertility soil was the most unstable, with the smallest soil carbon pool. Compared to the 0～20 cm deep soil, both the organic carbon mineralization rate and the cumulative mineralization amount of soil organic carbon of the 20～40 cm deep soil were lower for the same soil fertility level, which indicated that the surface soil stability was poor, and inhibited the fixation of organic carbon. Accompanied by the process of soil organic carbon mineralization, the soil microbial biomass carbon(MBC)and dissolved organic carbon(DOC)contents were lower than the initial stage. The mineralization potential(Cp)of soil organic carbon was positively correlated with the soil organic carbon, total nitrogen, ammonium nitrogen, nitrate nitrogen, MBC, and DOC contents. Soil organic carbon mineralization is an important part of the carbon cycle in the terrestrial ecosystem, and the stability of soil organic carbon at different soil depths likely would be affected when the soil fertility varies. This study provides data support for understanding the dynamic trend of soil organic carbon in soils with different fertility levels and the benefits of carbon sequestration and emission reduction in maize fields.更多还原