As commonly used harvest residue management practices in subtropical plantations, stem only harvesting (SOH) and whole tree harvesting (WTH) are expected to affect soil organic carbon (SOC) content. However, knowledge on how SOC and its fractions (POC: particulate organic carbon; MAOC: mineral-associated organic carbon) respond to different harvest residue managements is limited. In this study, a randomized block experiment containing SOH and WTH was conducted in a Chinese fir () plantation. The effect of harvest residue management on SOC and its fractions in topsoil (0–10 ​cm) and subsoil (20–40 ​cm) was determined. Plant inputs (harvest residue retaining mass and fine root biomass) and microbial and mineral properties were also measured. The responses of SOC and its fractions to different harvest residue managements varied with soil depth. Specifically, SOH enhanced the content of SOC and POC in topsoil with increases of 15.9% and 29.8%, respectively, compared with WTH. However, SOH had no significant effects on MAOC in topsoil and SOC and its fractions in subsoil. These results indicated that the increase in POC induced by the retention of harvest residue was the primary contributor to SOC accumulation, especially in topsoil. The harvest residue managements affected SOC and its fractions through different pathways in topsoil and subsoil. The plant inputs (the increase in fine root biomass induced by SOH) exerted a principal role in the SOC accumulation in topsoil, whereas mineral and microbial properties played a more important role in regulating SOC dynamics than plants inputs in subsoil. The retention of harvest residues can promote SOC accumulation by increasing POC, and is thus suggested as an effective technology to enhance the soil carbon sink for mitigating climate change in plantation management.

中文翻译：

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杉木人工林收获残留物的滞留通过增加颗粒有机碳促进表土有机碳的积累


作为亚热带种植园常用的收获残留物管理做法，仅茎收获（SOH）和整树收获（WTH）预计会影响土壤有机碳（SOC）含量。然而，关于 SOC 及其组分（POC：颗粒有机碳；MAOC：矿物相关有机碳）如何响应不同收获残留物管理的知识有限。本研究在杉木人工林中进行了含有SOH和WTH的随机区组试验。确定了收获残留物管理对表土 (0-10 cm) 和底土 (20-40 cm) SOC 及其部分的影响。还测量了植物投入（收获残留物保留质量和细根生物量）以及微生物和矿物特性。 SOC及其分数对不同收获残留物管理的响应随土壤深度的不同而变化。具体而言，与WTH相比，SOH提高了表土中SOC和POC的含量，分别增加了15.9%和29.8%。然而，SOH对表土中的MAOC和下土中的SOC及其组分没有显着影响。这些结果表明，收获残留物的保留引起的 POC 增加是 SOC 积累的主要贡献者，特别是在表土中。收获残留物管理通过表土和底土的不同途径影响 SOC 及其部分。植物输入（SOH引起的细根生物量增加）在表土中的SOC积累中发挥着主要作用，而矿物质和微生物特性在调节SOC动态方面比植物在底土中的输入发挥着更重要的作用。 收获残留物的保留可以通过增加POC来促进SOC积累，因此被认为是种植园管理中增强土壤碳汇以缓解气候变化的有效技术。