Research Institute of Subtropical Forestry, Chinese Academy of Forestry, Hangzhou 311400, China; Qianjiangyuan Forest Ecosystem Research Station, National Forestry and Grassland Administration of China, Hangzhou 311400, China.
Xin'an'jiang Forest Farm, Jiande, Zhejiang 311600, China.
Sci Total Environ. 2023 Dec 20;905:167275. doi: 10.1016/j.scitotenv.2023.167275. Epub 2023 Sep 21.
A vast expanse of Moso bamboo (Phyllostachys pubescens J.Houz.) forests in subtropical areas was once intensively managed but has been abandoned in recent years. However, the response of soil organic carbon (SOC) to abandonment management remains unclear, partly because how carbon-degrading enzymes vary with abandonment management and the role of this change in the soil carbon cycle are still poorly understood, which restricts the scientific evaluation of carbon sink benefits of these abandoned Moso bamboo forests. The results of the survey, based on 40 Moso bamboo forests, showed that compared with intensive management, abandonment management for 7-10 and 11-14 years exhibited a significant decrease in ligninase activities (a reduction of 12.14 % and 44.41 %, respectively) and a significant increase in SOC content (an increase of 49.39 % and 52.64 %, respectively). However, abandonment management did not affect cellulase activities or easily oxidizable organic carbon content (p > 0.05), but significantl increased non-easily oxidizable organic carbon (p < 0.05). Furthermore, the total nitrogen (TN) content and pH value increased with prolonged abandonment, and these trade-offs between ligninase and cellulase were primarily driven by pH and TN. The ligninase-to-cellulase activities ratio is the most key factor affecting NEOC and SOC changes in abandoned Moso bamboo forests. Together, these findings demonstrate the response of carbon-degrading enzyme trade-offs to abandonment management and highlight the role of these trade-offs in controlling SOC accumulation. In addition, the different responses of different SOC fractions to abandonment management deserve attention in future studies.
大面积的亚热带毛竹（Phyllostachys pubescens J.Houz.）林曾经得到集约化管理，但近年来已被废弃。然而，土壤有机碳（SOC）对废弃管理的响应仍不清楚，部分原因是碳降解酶如何随废弃管理而变化，以及这种变化在土壤碳循环中的作用仍知之甚少，这限制了对这些废弃毛竹林碳汇效益的科学评估。基于 40 个毛竹林的调查结果表明，与集约化管理相比，7-10 年和 11-14 年的废弃管理使木质素酶活性显著降低（分别降低 12.14%和 44.41%），SOC 含量显著增加（分别增加 49.39%和 52.64%）。然而，废弃管理并不影响纤维素酶活性或易氧化有机碳含量（p>0.05），但显著增加了难氧化有机碳（p<0.05）。此外，随着废弃时间的延长，总氮（TN）含量和 pH 值增加，木质素酶和纤维素酶之间的这种权衡主要受 pH 和 TN 的驱动。木质素酶与纤维素酶活性的比值是影响废弃毛竹林 NEOC 和 SOC 变化的最关键因素。综上所述，这些发现表明了碳降解酶权衡对废弃管理的响应，并强调了这些权衡在控制 SOC 积累中的作用。此外，在未来的研究中，不同 SOC 组分对废弃管理的不同响应值得关注。
