植物生态学报 ›› 2023, Vol. 47 ›› Issue (5): 618-628.DOI: 10.17521/cjpe.2022.0187

所属专题: 凋落物

• 研究论文 • 上一篇    下一篇

亚热带天然阔叶林凋落物分解过程中活性、惰性碳氮的动态特征

李慧璇, 马红亮(), 尹云锋, 高人   

  1. 福建师范大学湿润亚热带山地生态国家重点实验室培育基地, 福建师范大学地理科学学院, 福州 350007
  • 收稿日期:2022-04-06 接受日期:2022-09-05 出版日期:2023-05-20 发布日期:2023-02-24
  • 通讯作者: *(kyleyuechina@163.com)
  • 作者简介:李慧璇: ORCID:0009-0004-4907-6601
  • 基金资助:
    国家自然科学基金(31922052);国家自然科学基金(32171641);国家自然科学基金(32022056)

Dynamic of labile, recalcitrant carbon and nitrogen during the litter decomposition in a subtropical natural broadleaf forest

LI Hui-Xuan, MA Hong-Liang(), YIN Yun-Feng, GAO Ren   

  1. Cultivation Base of State Key Laboratory of Humid Subtropical Mountain Ecology, School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China
  • Received:2022-04-06 Accepted:2022-09-05 Online:2023-05-20 Published:2023-02-24
  • Supported by:
    National Natural Science Foundation of China(31922052);National Natural Science Foundation of China(32171641);National Natural Science Foundation of China(32022056)

摘要:

为最大程度模拟森林凋落物分解实际状况, 探究亚热带天然阔叶林凋落物的分解动态特征, 该研究采用凋落物分解“三明治”法, 在野外原位分解的凋落物上, 平均间隔3个月在积累的凋落物上铺设一层尼龙网(60目, 1.2 m × 1.95 m)。3年后共获取11层不同分解程度的凋落物, 分析其活性和惰性碳、氮含量变化。结果表明: 1)在整个分解过程中, 活性、惰性碳参与分解的时间不同, 水溶性有机碳最早开始释放, 持续释放时间长(295 d); 惰性碳分解滞后(4层, 422 d); 而酸水解有机碳可能在分解中受二者的影响, 变化波动大。2)与碳相比, 氮在整个分解阶段的动态更为复杂, 表现出明显的周期性, 即固持(1-3层, 90-295 d)—释放(4-6层, 422-670 d)—固持(7-11层, 802-1 200 d)。3)凋落物原状分解有利于氮的截留和保存。一方面, 分解前期上层凋落物中的活性物质受淋溶作用在下层积累, 从而降低淋失的风险; 另一方面, 分解后期惰性碳氮偏向于底层积累, 利于碳氮的固存。可见, 森林凋落物的自然分解状态有利于凋落物惰性碳氮更好地归还土壤。因此, 在森林管理中要注重凋落物层的保护, 让其在自然状态下分解, 助力土壤碳氮的稳定与保留。

关键词: 凋落物分解, 水溶性碳, 水溶性氮, 酸水解碳, 酸水解氮, 惰性碳, 惰性氮, 阔叶林

Abstract:

Aims In order to simulate the actual situation to the greatest extent, the decomposition dynamics of litter in subtropical natural broadleaf forests were explored using a litter “sandwichs” method.
Methods A three-year field in-situ experiment of undisturbed litter layer decomposition was carried out in a natural subtropical broadleaf forest. Eleven layers of litter with different decomposition degrees were isolated accurately by laying nylon nets (60 mesh, 1.2 m × 1.95 m) every three months, and the dynamic of labile and recalcitrant carbon (C) and nitrogen (N) contents were analyzed.
Important findings The results showed that: 1) During the whole decomposition process, the labile and recalcitrant C participated in the decomposition at different times. Water-soluble organic C began to decompose first and sustained release time up to 295 d, while the recalcitrant C began to decompose behind for many days (at 4th layer, 422 d), and the change in acid-hydrolyzed organic C fluctuated greatly due to the fates of the labile and recalcitrant C. 2) Compared with that of C, the dynamics of N in the whole decomposition stage were more complex, to some extent, with obvious periodicity, that is, N retention (1st to 3rd layers, 90-295 d), release (4th to 6th layers, 422-670 d), and retention again (7th to 11th layers, 802-1 200 d). 3) The undisturbed decomposition of litterfall layer was beneficial to the N storage. On the one hand, at the early stage of decomposition, the labile substances from the upper litterfall were accumulated in the lower layer due to the leaching, which reduced the risk of their leaching loss. On the other hand, recalcitrant C and N was prone to accumulate in the bottom layers, which was beneficial to C and N retention. It can be concluded that the natural decomposition state of forest litter layer is conducive to the return of litter recalcitrant C and N into soil. Therefore, more attention should be paid to the protection of litter layer in forest management, which could ensure litter decomposing in its natural state to improve the stabilization and enrichment of C and N.

Key words: litter decomposition, water-soluble carbon, water-soluble nitrogen, acid hydrolyzed carbon, acid hydrolyzed nitrogen, recalcitrant carbon, recalcitrant nitrogen, broadleaf forest