目的 获得种植马铃薯土壤有机碳库调控的水肥管理模式，并揭示土壤酶活性对土壤有机碳组分和碳库管理指数(Carbon pool management index，CPMI)的影响。方法 在南宁市防雨棚内进行2种滴灌灌水量水平(高灌水量：苗期、块茎形成期、块茎膨大期和淀粉积累期土壤含水量分别保持在田间持水量的60%~70%、70%~80%、75%~85%和50%~60%；低灌水量：苗期、块茎形成期、块茎膨大期和淀粉积累期土壤含水量保持在田间持水量的50%~60%、60%~70%、70%~80%和40%~50%)和3种滴灌施肥比例(NK100-0：N、K肥以100%作基肥土施；NK70-30：N、K肥以70%作基肥土施，30%作滴灌追肥；NK50-50：N、K肥以50%作基肥土施，50%作滴灌追肥)的田间试验。测定马铃薯收获后土壤总有机碳(Total organic carbon，TOC)、可溶性有机碳(Dissolved organic carbon，DOC)、微生物量碳(Microbial biomass carbon，MBC)、活性有机碳(Labile organic carbon，LOC)含量以及蔗糖酶、纤维素酶和过氧化氢酶活性，计算碳库管理指数，并分析土壤有机碳库组分含量和碳库管理指数与土壤酶活性之间的关系。结果 滴灌灌水量显著影响土壤有机碳及其组分含量。相同施肥比例下，高灌水量土壤有机碳及其组分含量、CPMI和蔗糖酶活性较低灌水量土壤高。高灌水量下，NK50-50土壤TOC含量分别比NK100-0和NK70-30提高15.2%和7.1%，NK50-50土壤LOC含量较NK100-0增加25.0%，且高灌水量NK50-50处理土壤TOC和LOC含量显著高于其他处理。在相同滴灌灌水量下，滴灌施肥比例对3种酶活性的影响不显著。土壤蔗糖酶活性以高灌水量NK50-50处理最高。高灌水量下NK50-50土壤碳库指数(Carbon pool index，CPI)和CPMI比NK100-0分别提高15.1%和25.8%；低灌水量下NK50-50土壤CPI和CPMI比NK100-0分别提高12.6%和8.4%。所有处理土壤CPI和CPMI以高灌水量NK50-50处理较高。此外，土壤TOC、DOC和MBC含量均与蔗糖酶活性呈极显著或显著正相关，相关系数分别为0.61、0.48和0.46。结论 高灌水量NK50-50处理提高了土壤有机碳及其组分含量和蔗糖酶活性，可作为马铃薯种植土壤有机碳库调控的水肥管理模式；土壤TOC、DOC和MBC含量受到土壤蔗糖酶活性的影响。
Objective The aim was to obtain a water and fertilizer management mode that regulates potato-planting soil organic carbon storage, and reveal the influence of soil enzyme activity on soil organic carbon fraction and carbon pool management index (CPMI). Method Field experiment was carried out in Nanning under the rain-shelter condition with two drip irrigation levels (high irrigation amount: Soil water content was maintained at 60%–70%, 70%–80%, 75%–85% and 50%–60% of field capacity at the seedling, tuber formation, tuber expansion and starch accumulation stages, respectively; Low irrigation amount: Soil water content was maintained at 50%–60%, 60%–70%, 70%–80% and 40%–50% of field capacity at the seedling, tuber formation, tuber expansion and starch accumulation stages, respectively) and three drip fertigation ratios (NK100-0: All N,K fertilizer were applied to soil as base fertilizer; NK70-30: 70% N,K fertilizer were applied to soil as base fertilizer and 30% as topdressing with drip fertigation; NK50-50: 50% N,K fertilizer were applied to soil as base fertilizer and 50% as topdressing with drip fertigation). The contents of total organic carbon (TOC), dissolved organic carbon (DOC), microbial biomass carbon (MBC) and labile organic carbon (LOC) and the activities of sucrase, cellulase and catalase in the soils were measured after harvesting the potato. Then CPMI was calculated and the relationships of soil organic carbon fraction and CPMI with soil enzyme activities were analyzed. Result Drip irrigation amount affected organic carbon contents and components in the soils significantly. Under the same fertigation ratio, high irrigation amount had higher organic carbon contents and components, CPMI and sucrase activity in the soils than those of low irrigation amount. Under the high irrigation amount condition, NK50-50 increased TOC content by 15.2% and 7.1% respectively compared with NK100-0 and NK70-30, and NK50-50 increased LOC content by 25.0% compared with NK100-0. Moreover, NK50-50 of high irrigation amount treatment had significant higher contents of TOC and LOC than those of other treatments. Under the same drip irrigation amount, the effect of drip fertigation ratio on the activities of three enzymes was not significant. Among all treatments, NK50-50 of high irrigation amount treatment had the highest sucrase activity. Compared with NK100-0, NK50-50 increased soil CPI and CPMI by 15.1% and 25.8% respectively under the high irrigation amount condition, and NK50-50 increased carbon pool index (CPI) and CPMI by 12.6% and 8.4% respectively under the low irrigation amount condition. Among all treatments, NK50-50 of high irrigation amount treatment had higher CPI and CPMI. In addition, soil TOC, DOC and MBC were extremely significantly or significantly correlated with the sucrase activity (with correlation coefficients of 0.61, 0.48 and 0.46, respectively). Conclusion NK50-50 of high irrigation amount treatment increases the contents of organic carbon and its components and sucrase activity in soil, and can be used as the water and fertilizer management mode regulating potato-planting soil organic carbon storage. Soil sucrase activity affects the contents of TOC, DOC and MBC.