Zhang Yu-Jian, Song Ya-Li, Wang Ke-Qin, Yang Xiao-Yu, Xing Jin-Mei, Zhang Zhuan-Min
College of Ecology and Environment, Southwest Forestry University, Kunming 650224, China.
Ying Yong Sheng Tai Xue Bao. 2020 Aug;31(8):2523-2532. doi: 10.13287/j.1001-9332.202008.034.
From February 2018 to January 2019, a field experiment of simulated nitrogen (N) depo-sition was conducted in and plantations in the subalpine region of central Yunnan, China. The litterbag method was used for litter (leaf and twig) decomposition experiment in both plantations. Four levels of N addition were applied, ., control (CK, 0 g N·m·a), low nitrogen (LN, 5 g N·m·a), medium nitrogen (MN, 15 g N·m·a), and high nitrogen (HN, 30 g N·m·a). The results showed that the annual decomposition rates of leaf and twig in were 34.8% and 18.0%, which were higher than the 32.2% (leaf) and 16.1% (twig) in Under N deposition, the LN treatment reduced the time of 95% mass loss of leaf and twig litter in by 0.202 and 1.624 years, the MN treatment reduced by 0.045 and 1.437 years, and the HN treatment increased by 0.840 and 2.112 years, respectively. In the plantation, the LN treatment reduced the time of 95% mass loss of leaf and twig litter by 0.766 and 4.053 years, while the MN treatment increased by 0.366 and 0.455 years, and the HN treatment increased by 0.826 and 0.906 years, respectively. Litter (leaf and twig) decomposition of both and were promoted by low N treatment and inhibited by high N treatment. The effects of N deposition on litter decomposition of two plantations were significantly correlated with the contents of cellulose and lignin in litter. In conclusion, the responses of litter decomposition to N deposition mainly depended on the litter substrate, especially cellulose and lignin contents.
2018年2月至2019年1月，在中国云南中部亚高山地区的[具体名称1]和[具体名称2]人工林中进行了模拟氮沉降的田间试验。在两个人工林中均采用凋落物袋法进行凋落物（树叶和细枝）分解试验。设置了四个氮添加水平，即对照（CK，0 g N·m⁻²·a⁻¹）、低氮（LN，5 g N·m⁻²·a⁻¹）、中氮（MN，15 g N·m⁻²·a⁻¹）和高氮（HN，30 g N·m⁻²·a⁻¹）。结果表明，[具体名称1]中树叶和细枝的年分解率分别为34.8%和18.0%，高于[具体名称2]中的32.2%（树叶）和16.1%（细枝）。在氮沉降条件下，LN处理使[具体名称1]中树叶和细枝凋落物95%质量损失的时间分别减少了0.202年和1.624年，MN处理分别减少了0.045年和1.437年，HN处理分别增加了0.840年和2.112年。在[具体名称2]人工林中，LN处理使树叶和细枝凋落物95%质量损失的时间分别减少了0.766年和4.053年，而MN处理分别增加了0.366年和0.455年，HN处理分别增加了0.826年和0.906年。低氮处理促进了[具体名称1]和[具体名称2]的凋落物（树叶和细枝）分解，高氮处理则抑制了分解。氮沉降对两个人工林凋落物分解的影响与凋落物中纤维素和木质素的含量显著相关。总之，凋落物分解对氮沉降的响应主要取决于凋落物底物，尤其是纤维素和木质素含量。
