【摘要】 【目的】明确冻融条件对土壤活性有机碳影响程度，为黑土区有机碳保持和碳平衡的研究提供基础数据和理论依据。【方法】以德惠地区典型中层黑土为研究对象，通过冻融控制试验，研究不同冻融频次、冻结时间、冻融温度及土壤含水量对土壤活性有机碳的影响。【结果】土壤活性有机碳组分对冻融条件的响应差异显著。土壤可溶性有机碳、轻组有机碳、颗粒有机碳含量随着冻融频次的增加逐渐增加，当冻融20次后，含量变化幅度较小，逐渐趋于稳定；土壤微生物量碳含量在冻融12次后处于0.160～0.164 g kg^-1之间波动。冻结温度降低、融化温度升高均可促进土壤可溶性有机碳、轻组有机碳和颗粒有机碳含量增加，而土壤微生物量碳含量则随冻结温度的降低而降低，随融化温度的升高而增加，但含量仍比对照处理低10.42%～24.48%。土壤可溶性有机碳、轻组有机碳和颗粒有机碳含量随着冻结时间的增加差异显著，冻结时间为12～48 h时，增幅较大；冻结时间增加使得土壤微生物量碳含量显著降低，冻结时间为96 h时，降幅可达52.60%。随着土壤含水量增加可溶性有机碳、轻组有机碳和颗粒有机碳含量逐渐增加，当含水量为田间持水量的80%～100%时，轻组有机碳含量增加最显著，增幅达到9.69%～38.48%；而土壤微生物量碳含量则逐渐降低，当含水量为田间持水量的80%～100%时，含量降低不显著。【结论】冻融循环有利于增强或维持土壤有机碳含量，频繁的冻融作用能够提高部分活性有机碳组分含量，促进土壤养分循环。更多还原

【Abstract】 [Objective] Conducting research on the impact of freeze-thaw conditions on soil active organic carbon can provide basic data and theoretical basis for the study of organic carbon conservation and carbon balance in black soil areas. [Method] Taking typical middle layer black soil in Dehui area as the research object, the effects of different freeze-thaw cycles, freezing time, freeze-thaw temperature,and moisture content on soil active organic carbon were investigated through freeze-thaw control experiments. [Result] There were significant differences in the response of soil active organic carbon components to freeze-thaw conditions. The content of Dissolved Organic Carbon（DOC）, Light Organic Carbon（LFOC）, and Particulate Organic Carbon（POC） in soil gradually increases with the increase of freeze-thaw cycles, and the growth rate slows down after 20 freeze-thaw cycles; Soil Microbial Biomass Carbon（MBC）fluctuates between 0.160 g kg^-1 and 0.164 g kg^-1 after 12 freeze-thaw cycles. Both a decrease in freezing temperature and an increase in melting temperature can promote an increase in soil DOC, LFOC, and POC content, while the soil MBC content decreases with a decrease in freezing temperature and increases with an increase in melting temperature. However, the content still decreases by 10.42% to24.48% compared to the control state. The content of soil DOC, LFOC, and POC showed significant differences with the increase of freezing time, with a significant increase from 12 to 48 hours; The increase in freezing time resulted in a significant decrease in soil MBC content, with a decrease of 52.60% at 96 hours of freezing time. As the moisture content increases, the content of soil DOC, LFOC, and POC gradually increases. When the relative moisture content is between 80% and 100%, the increase in LFOC content is most significant, ranging from 9.69% to 38.48%; The soil MBC content gradually decreases, and the decrease tends to be gradual when the relative water content is between 80% and 100%. [Conclusion] The freeze-thaw cycle is beneficial for enhancing or maintaining soil organic carbon, and frequent freeze-thaw cycles can increase the content of some active organic carbon components and promote soil nutrient cycling.更多还原