Forest Ecology & Stable Isotope Center, College of Forestry, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
Xiqin Forestry Station of Fujian Agriculture and Forestry University, Nanping 353001, Fujian, China.
Ying Yong Sheng Tai Xue Bao. 2021 Mar;32(3):825-835. doi: 10.13287/j.1001-9332.202103.008.
Litter is one of the most important factors controlling the accumulation, stabilization, and turnover of soil organic carbon (SOC) in forests. There is a knowledge gap of the impacts of aboveground and belowground litter inputs on the balance of new and old SOC under different forests in subtropical region. We examined the effects of aboveground and belowground litter inputs on SOC turnover using isotopic tracing technique, based on a 3-year C3 plants/C4 soil replacement experiment in natural forest (NF), Masson pine () plantation (PM) and Chinese fir () plantation (CL). Our results showed that forest types, litter treatments, and sampling time significantly affected SOC contents, δC, new and old SOC contents. Moreover, there were significant interactions between forest types and litter treatments. Litter input increased SOC content and net SOC increment, with higher sensitivity of NF than CL. Litter inputs decreased soil δC, with lower values in NF and PM compared to CL. For PM, the new SOC content in belowground litter treatment was significantly higher than that in aboveground litter treatment. The contents of old SOC were lower in belowground litter treatment than aboveground litter treatment in the NF and CL. Above- and below-ground biomass were positively correlated with SOC content and net increment. Belowground litter biomass were positively correlated with soil C/N ratio and new SOC content. Our results implied that belowground litter input had stronger effects on SOC turnover compared to aboveground litter input, with the effects varying among different forests. Our results provided new information on SOC accumulation and on sustainable management of the typical forests in subtropical region.
垃圾是控制森林土壤有机碳（SOC）积累、稳定和转化的最重要因素之一。在亚热带地区，不同森林地上和地下凋落物输入对新老 SOC 平衡的影响存在知识空白。我们通过 C3 植物/C4 土壤替代实验，以天然林（NF）、马尾松（PM）和杉木（CL）人工林为研究对象，利用同位素示踪技术研究了地上和地下凋落物输入对 SOC 周转的影响。结果表明，森林类型、凋落物处理和采样时间显著影响 SOC 含量、δC、新老 SOC 含量。此外，森林类型和凋落物处理之间存在显著的相互作用。凋落物输入增加了 SOC 含量和净 SOC 增量，天然林的敏感性高于杉木林。凋落物输入降低了土壤 δC，与杉木林相比，天然林和马尾松林的土壤 δC 值较低。对于马尾松林，地下凋落物处理的新 SOC 含量显著高于地上凋落物处理。与地上凋落物处理相比，天然林和杉木林地下凋落物处理的老 SOC 含量较低。地上和地下生物量与 SOC 含量和净增量呈正相关。地下凋落物生物量与土壤 C/N 比和新 SOC 含量呈正相关。研究结果表明，与地上凋落物输入相比，地下凋落物输入对 SOC 周转的影响更强，不同森林的影响也不同。研究结果为亚热带典型森林的 SOC 积累和可持续管理提供了新的信息。
