College of Agronomy, Northwest Agriculture & Forestry University, Yangling, 712100, China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling, 712100, Shaanxi, China.
College of Agronomy, Northwest Agriculture & Forestry University, Yangling, 712100, China; Shaanxi Engineering Research Center of Circular Agriculture, Yangling, 712100, Shaanxi, China.
Environ Res. 2024 Dec 15;263(Pt 3):120285. doi: 10.1016/j.envres.2024.120285. Epub 2024 Nov 2.
Litter plays a crucial role in soil ecosystems. However, the differences in decomposition between leaf-litter and root-litter and their relative contributions to soil carbon pools and stability are not yet clear. Therefore, we conducted a 450-day in situ decomposition experiment in a semi-arid grassland to investigate the effects of soil biophysical and chemical properties on litter decomposition and to elucidate the dynamics of soil carbon pools during the decomposition process. The results showed that the decomposition rate (K) of leaf-litter was significantly higher than that of root-litter, and litter quality was the most important factor affecting the K of leaf-litter (58%) and root-litter (63%). Leaf-litter decomposition was more effective in promoting the increase in soil leucine aminopeptidase and β-1,4-glucosidase activities, as well as the accumulation of microbial biomass carbon (MBC), particulate organic carbon (POC), and dissolved organic carbon (DOC), compared to root-litter. However, the difference in the impact of leaf-litter and root-litter on soil organic carbon (SOC) was not significant. The decomposition of leaf-litter contributed more significantly to enhancing the soil carbon pool management index (CPMI) compared to root-litter, with increases of 39% and 25%, respectively. In contrast, leaf-litter decomposition significantly reduced the mineral-associated organic carbon (MAOC) and the MAOC/POC ratio, while root-litter decomposition significantly increased the MAOC and MAOC/POC. Random forest, partial correlation, and path analysis indicated that the effects of leaf-litter and root-litter decomposition on CPMI were mainly regulated by decomposition time and soil carbon components, while the effects on MAOC/POC were mainly controlled by litter quality. The results demonstrate that both leaf-litter and root-litter can enhance soil carbon storage and CPMI, but root-litter may be more beneficial for soil carbon pool stability. These results further contribute to the understanding of the continuous system of litter-soil carbon pools.
凋落物在土壤生态系统中起着至关重要的作用。然而，叶凋落物和根凋落物的分解差异及其对土壤碳库和稳定性的相对贡献尚不清楚。因此，我们在半干旱草原进行了一项为期 450 天的原位凋落物分解实验，以研究土壤生物物理和化学性质对凋落物分解的影响，并阐明分解过程中土壤碳库的动态变化。结果表明，叶凋落物的分解速率（K）明显高于根凋落物，凋落物质量是影响叶凋落物（58%）和根凋落物（63%）K 的最重要因素。与根凋落物相比，叶凋落物分解更有效地促进土壤亮氨酸氨肽酶和β-1,4-葡萄糖苷酶活性以及微生物生物量碳（MBC）、颗粒有机碳（POC）和溶解有机碳（DOC）的积累。然而，叶凋落物和根凋落物对土壤有机碳（SOC）的影响没有显著差异。与根凋落物相比，叶凋落物分解对土壤碳库管理指数（CPMI）的贡献更大，分别增加了 39%和 25%。相比之下，叶凋落物分解显著降低了矿物结合有机碳（MAOC）和 MAOC/POC 比值，而根凋落物分解显著增加了 MAOC 和 MAOC/POC。随机森林、偏相关和路径分析表明，叶凋落物和根凋落物分解对 CPMI 的影响主要受分解时间和土壤碳组分的调节，而对 MAOC/POC 的影响主要受凋落物质量的控制。结果表明，叶凋落物和根凋落物都可以增强土壤碳储存和 CPMI，但根凋落物可能更有利于土壤碳库的稳定性。这些结果进一步加深了对凋落物-土壤碳库连续系统的理解。
