Global climate change has been found to affect plant net primary production and thereby could modify the quantity and quality of aboveground litter, which may consequently affect soil organic carbon (SOC). Whether those changes have influenced the chemical components of SOC is still unclear, especially for the soil beneath the surface soil. This study examined the changes in biopolymers (lignin, substituted fatty acids, amino sugars) in 0–10 cm and 10–20 cm soil depth in a temperate forest after five years of aboveground litter addition or removal treatments. The results showed that although SOC and soil nitrogen contents were not influenced by litter manipulation, the lignin phenols and substituted fatty acids contents in SOC of 10–20 cm soil were significantly higher in litter addition treatment compared to litter removal treatment, suggesting a selective accumulation pathway for these plant biopolymers in the 10–20 cm soil under litter manipulation. Soil amino sugar content, however, was not influenced by litter manipulation, although microbial biomass carbon (MBC) and nitrogen in 0–10 cm soil were significantly higher in litter addition plots due to the significantly higher substrate availability (dissolved organic carbon) and nutrient availability (total dissolved nitrogen) than those in the control. Although higher MBC could increase decomposition of SOC, this effect did not counterbalance the effect of higher aboveground litter input in litter addition plots, but rather changed the composition of SOC toward compounds of a purportedly more stable composition. The effects of aboveground litter removal were not entirely in contrast to the effects of aboveground litter addition on SOC, hinting that belowground inputs could sustain the storage of SOC for at least five years under aboveground litter removal treatment. The changes in the chemical composition of SOC under litter manipulation for five years suggested the potential changes in SOC stability and pool size in the future, especially in the 10–20 cm soil, to which more attention should be paid in future litter manipulation studies.

已发现全球气候变化会影响植物净初级生产，从而可能改变地上凋落物的数量和质量，从而可能影响土壤有机碳 (SOC)。这些变化是否影响了 SOC 的化学成分尚不清楚，特别是对于表层土壤以下的土壤。本研究检查了温带森林中 0-10 厘米和 10-20 厘米土壤深度的生物聚合物（木质素、取代脂肪酸、氨基糖）在经过五年的地上凋落物添加或清除处理后的变化。结果表明，虽然 SOC 和土壤氮含量不受凋落物处理的影响，但与凋落物处理相比，添加凋落物处理的 10-20 cm 土壤 SOC 中木质素酚类和取代脂肪酸含量显着升高，表明在凋落物处理下这些植物生物聚合物在 10-20 厘米土壤中的选择性积累途径。然而，土壤氨基糖含量不受凋落物操纵的影响，尽管 0-10 厘米土壤中的微生物生物量碳 (MBC) 和氮在凋落物添加地块中显着更高，因为底物可用性（溶解有机碳）和养分显着更高可利用性（总溶解氮）高于对照。尽管较高的 MBC 可以增加 SOC 的分解，但这种效应并没有抵消在凋落物添加图中较高的地上凋落物输入的影响，而是将 SOC 的组成改变为据称组成更稳定的化合物。地上垃圾清除的影响与地上垃圾添加对 SOC 的影响并不完全相反，这表明在地上垃圾清除处理下，地下输入可以维持 SOC 的存储至少五年。5 年凋落物处理下 SOC 化学成分的变化表明未来 SOC 稳定性和池大小可能发生变化，特别是在 10-20 cm 土壤中，在未来的凋落物处理研究中应更加关注这一点。