Wei Wen-Tao, Ni Xiang-Yin, Yue Kai, Guo Hong-Rong, Wu Ruo-Bing, Zhu Ling, Wu Fu-Zhong
Key Laboratory for Humid Subtropical Eco-Geographical Processes of the Ministry of Education, School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China.
Ying Yong Sheng Tai Xue Bao. 2022 Aug;33(8):2121-2128. doi: 10.13287/j.1001-9332.202208.005.
To assess the dynamics and spectral characteristics of dissolved organic matter of twig litter in continuous increase stage, peak stage, and continuous decrease stage of twig litter production in different types of forest in middle subtropical China, a field experiment was conducted in natural forest, secondary forest and plantation. The results showed that litter production stage and forest type significantly affected the content and spectral characteristics of dissolved organic matter of twig litter were . Compared with the secondary forest and plantation, natural forest had higher dissolved organic carbon (DOC) content and lower special ultraviolet-visible absorption values at 254, 260 and 280 nm (SUVA, SUVA, SUVA) at the continuous decrease stage of twig litter production, indicating high twig litter quality of natural forest and high cycling efficiency with dissolved organic matter in the natural forest at this stage. In contrast, the higher contents of total nitrogen (TN), total phosphorus (TP), total dissolved nitrogen (TDN), total dissolved phosphorus (TDP), and lower DOC:TDP and TDN:TDP ratios of twig litter in the plantation were observed at the peak stage of twig litter production, while no differences were detected in dissolved organic matter contents and spectral values in the secondary forest among the stages. In addition, the DOC, TDN, TDP of twig litter were negatively correlated with temperature and precipitation in the natural forests and secondary forests, but TDN and TDP of twig litter were positively correlated with temperature and precipitation in the plantations. These results suggested that the higher nutrient content at the peak stage of twig litter production in the plantation might lead to more efficient material cycling and that there would be a higher efficiency of material cycling for twig litter dissolved organic matter in natural forest at reduction stage of twig litter production.
为了评估中国中亚热带不同类型森林中细枝凋落物在持续增加阶段、峰值阶段和持续减少阶段溶解有机物的动态变化和光谱特征，在天然林、次生林和人工林中进行了田间试验。结果表明，凋落物生产阶段和森林类型对细枝凋落物溶解有机物的含量和光谱特征有显著影响。与次生林和人工林相比，在细枝凋落物生产的持续减少阶段，天然林的溶解有机碳（DOC）含量较高，在254、260和280 nm处的特定紫外可见吸收值（SUVA254、SUVA260、SUVA280）较低，表明天然林细枝凋落物质量较高，且该阶段天然林中溶解有机物的循环效率较高。相反，在细枝凋落物生产的峰值阶段，人工林中细枝凋落物的总氮（TN）、总磷（TP）、总溶解氮（TDN）、总溶解磷（TDP）含量较高，而DOC:TDP和TDN:TDP比值较低，而次生林中不同阶段的溶解有机物含量和光谱值没有差异。此外，天然林和次生林中细枝凋落物的DOC、TDN、TDP与温度和降水呈负相关，但人工林中细枝凋落物的TDN和TDP与温度和降水呈正相关。这些结果表明，人工林细枝凋落物生产峰值阶段较高的养分含量可能导致更高效的物质循环，而在细枝凋落物生产减少阶段，天然林细枝凋落物溶解有机物的物质循环效率更高。
