Chin J Plant Ecol ›› 2023, Vol. 47 ›› Issue (5): 618-628.DOI: 10.17521/cjpe.2022.0187

• Research Articles • Previous Articles     Next Articles

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)

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