【摘要】 为探究凋落物输入变化对土壤有机碳库的影响，明确凋落物对森林生态系统土壤碳循环的作用，以黄河三角洲滨海盐碱地柽柳人工林为研究对象，通过设置添加凋落物(LA)、去除凋落物(LR)和对照(CK)3种处理方法，分析凋落物不同输入变化对土壤理化性质、土壤有机碳及其组分的影响。结果表明：凋落物添加和去除处理影响土壤理化性质的变化，与对照相比，添加凋落物降低了土壤密度和含盐量，增加了土壤含水量和养分(全氮、全磷、全钾),而去除凋落物则相反。3种处理对土壤有机碳(SOC)及其储量以及活性有机碳组分的影响一致，均表现为LA处理影响最大，LR处理影响最小，其中LA处理比CK增加了SOC质量分数及储量，但增加不显著；LR处理则显著降低了SOC质量分数及其储量，土层深度(d)0<d≤10 cm土层，LR处理比CK处理的SOC质量分数及其储量分别显著降低了34.93%、12.66%,10 cm<d≤20 cm土层，LR处理比CK处理的SOC质量分数及其储量分别显著降低了24.27%、16.13%。LA处理的土壤SOC及可溶性有机碳(DOC)、易氧化有机碳(EOC)、微生物量碳(MBC)质量分数均出现明显的表聚现象，而LR处理影响则不显著，且DOC和MBC则出现随土层深度增加而增大的趋势。土壤惰性有机碳(ROC)质量分数在不同土层间存在差异，0<d≤10 cm土层，各处理表现为LA>CK>LR,10 cm<d≤20 cm土层，各处理则表现为CK>LA>LR,而在CK和LR处理出现随土层增加而增加的趋势，偏于向土层下方积累。土壤密度(BD)与SOC及其各组分呈负相关，而土壤含水量(WC)、全氮、全磷与SOC及EOC、MBC、DOC质量分数呈极显著正相关(P<0.01)。因此，不同处理方式及不同土层深度的土壤密度、全氮质量分数和土壤含水量是影响SOC及组分变化的主要环境因子。更多还原

【Abstract】 To investigate the impact of litter input changes on the soil organic carbon pool and to clarify the role of litter in soil carbon cycling in the forest ecosystem, Tamarix chinensis plantation in the coastal saline-alkali land of the Yellow River Delta was selected as the research subject. The one-year effects of different litter input changes on soil physico-chemical properties, soil organic carbon and its components were studied by setting up three treatments, including adding litter(LA), removing litter(LR), and control(CK). The results showed that both litter addition and removal treatments affected the changes in soil physico-chemical properties. Compared to the control, litter addition decreased soil bulk density and salinity, while increasing soil moisture and nutrients(total nitrogen, total phosphorus, total potassium). On the other hand, litter removal had the opposite effect. All three treatments exhibited consistent effects on soil organic carbon(SOC) and its reserves, as well as on the active organic carbon fractions, with the LA treatment demonstrating the greatest impact and the LR treatment the smallest. The LA treatment increased the SOC mass fraction and reserves compared to CK, however, these increases were not significant. The LR treatment significantly decreased the SOC mass fraction and its reserves, particularly in the soil layer at 0<d≤10 cm, where SOC mass fraction and reserves were markedly reduced by 34.93% and 12.66% respectively, and in the soil layer at 10 cm<d≤20 cm, where SOC mass fraction and reserves were markedly reduced by 24.27% and 16.13% respectively when compared to the CK treatment. The LA treatment demonstrated a clear surface aggregation phenomenon of SOC, dissolved organic carbon(DOC), easily oxidizable organic carbon(EOC), and microbial biomass carbon(MBC) mass fractions, while the LR treatment had no significant impact. Additionally, the DOC and MBC showed an increasing trend with increasing soil depth. The mass fractions of soil inert organic carbon(ROC) differed in different soil layers, with the LA treatment>CK treatment>LR treatment for 0<d≤10 cm soil layer and the CK treatment>LA treatment>LR treatment for 10 cm<d≤20 cm soil layer. However, ROC in CK and LR treatments showed a tendency to rise with increasing soil layers, tending to accumulate in the lower soil layer. Soil bulk density(BD) was negatively correlated with SOC and its components, while soil water content(WC), total nitrogen and total phosphorus were positively correlated with SOC, EOC, MBC and DOC. Hence, soil bulk density, total nitrogen mass fraction, and soil moisture under different treatments and at different soil depths are the main environmental factors influencing the variation of SOC and its fractions.更多还原