Anhui Province Key Laboratory of Forest Resources and Silviculture, Anhui Agricultural University, Hefei 230036, China; Huitong Experimental Station of Forest Ecology, CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Shenyang 110016, China.
Anhui Province Key Laboratory of Forest Resources and Silviculture, Anhui Agricultural University, Hefei 230036, China.
Sci Total Environ. 2024 May 15;925:171752. doi: 10.1016/j.scitotenv.2024.171752. Epub 2024 Mar 16.
Plant- and microbial-derived organic carbon, two components of the soil organic carbon (SOC) pool in terrestrial ecosystems, are regulated by increased atmospheric nitrogen (N) deposition. However, the spatial patterns and driving factors of the responses of plant- and microbial-derived SOC to N deposition in forests are not clear, which hinders our understanding of SOC sequestration. In this study, we explored the spatial patterns of plant- and microbial-derived SOC, and their responses to N addition and elucidated their underlying mechanisms in forest soils receiving N addition at four sites with various soil and climate conditions. Plant- and microbial-derived SOC were quantified using lignin phenols and amino sugars, respectively. N addition increased the total microbial residues by 20.5% on average ranging from 9.4% to 34.0% in temperate forests but not in tropical forests, and the increase was mainly derived from fungal residues. Lignin phenols increased more in temperate forests (average of 63.8%) than in tropical forests (average of 15.7%) following N addition. The ratio of total amino sugars to lignin phenols was higher in temperate forests than in tropical forests and decreased with N addition in temperate forests. N addition mainly regulated soil microbial residues by affecting pH, SOC, exchangeable Ca, gram-negative bacteria biomass, and the C:N ratio, while it mainly had indirect effects on lignin phenols by altering SOC, soil C:N ratio, and gram-negative bacteria biomass. Overall, our findings suggested that N deposition caused a greater increase in plant-derived SOC than in microbial-derived SOC and that plant-derived SOC would have a more important role in sequestering SOC under increasing N deposition in forest ecosystems, particularly in temperate forests.
植物和微生物来源的有机碳是陆地生态系统土壤有机碳（SOC）库的两个组成部分，它们受大气氮（N）沉降增加的调节。然而，森林中植物和微生物来源的 SOC 对 N 沉降的响应的空间格局和驱动因素尚不清楚，这阻碍了我们对 SOC 固存的理解。在这项研究中，我们在四个具有不同土壤和气候条件的站点，探索了受 N 添加影响的森林土壤中植物和微生物来源的 SOC 的空间格局及其对 N 添加的响应，并阐明了其潜在机制。分别使用木质素酚和氨基糖定量植物和微生物来源的 SOC。N 添加平均增加了 20.5%的总微生物残留物，范围从温带森林的 9.4%到 34.0%，但在热带森林中没有增加，增加的主要来源于真菌残留物。N 添加后，温带森林中木质素酚的增加量（平均 63.8%）高于热带森林（平均 15.7%）。温带森林中总氨基糖与木质素酚的比值高于热带森林，并且随着 N 添加而降低。N 添加主要通过影响 pH 值、SOC、可交换 Ca、革兰氏阴性菌生物量和 C:N 比来调节土壤微生物残留物，而通过改变 SOC、土壤 C:N 比和革兰氏阴性菌生物量来对木质素酚产生间接影响。总体而言，我们的研究结果表明，N 沉降导致植物来源的 SOC 增加大于微生物来源的 SOC，并且在森林生态系统中，N 沉降增加时，植物来源的 SOC 将在 SOC 固存中发挥更重要的作用，特别是在温带森林中。
