Hu Xin, Xie Tingting, Arif Muhammad, Ding Dongdong, Li Jiajia, Yuan Zhongxun, Li Changxiao
Key Laboratory of Eco-Environments in the Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Resource Conservation and Germplasm Innovation, College of Life Sciences, Southwest University, Chongqing 400715, China.
Biology (Basel). 2021 Nov 5;10(11):1141. doi: 10.3390/biology10111141.
Litter decomposition is an important soil nutrient source that promotes vegetation in deteriorated riparian zones worldwide. The periodic submergence and sediment burial effects on two prominent annual herbaceous plants ( and ) are little known in mega-reservoir settings. Our study focuses on the mass and carbon loss and nutrient release from and litter and changes in soil properties, which are important for riparian zone rehabilitation in the Three Gorges Dam Reservoir, China. This study adopted the litter bag method to explore the nutrient change characteristics and changes in soil properties at different sediment burial depths under flooding scenarios. Three burial depths (0 cm, 5 cm, and 10 cm) were used for these two plants, and the experiment lasted for 180 days. The results revealed that the litter decay rate was high at first in the incubation experiment, and the nutrient loss rate followed the pattern of K > P > N > C. The relationship between % C remaining and % mass remaining was nearly 1:1, and the total amount of P exhibited a leaching-enrichment-release state in the decomposition process. Nutrients were changed significantly in the soil and overlying water at the first decomposition stage. Still, the total soil nutrient change was insignificant at the end, except for the 10 cm burial of . Moreover, oxidation-reduction potential was the main factor in the litter decomposition process at different burial depths. This study indicated that sediment deposition reduced litter mass loss, slowed down the release of N and P, and retained more C, but promoted the release of K. Conclusively, in litter decomposition under waterlogging, the total soil nutrient content changed little. However, litter does more to the soil than that. Therefore, it is necessary to study the residual soil litter's continuous output after the water level declines for restoration purposes.
凋落物分解是一种重要的土壤养分来源，可促进全球退化河岸带的植被生长。在大型水库环境中，周期性淹没和沉积物掩埋对两种主要的一年生草本植物（和）的影响鲜为人知。我们的研究聚焦于和凋落物的质量、碳损失、养分释放以及土壤性质的变化，这些对于中国三峡大坝水库河岸带的恢复至关重要。本研究采用凋落物袋法，探究了水淹情景下不同沉积物掩埋深度的养分变化特征和土壤性质变化。对这两种植物设置了三个掩埋深度（0厘米、5厘米和10厘米），实验持续了180天。结果表明，在培养实验初期凋落物分解速率较高，养分损失率遵循K > P > N > C的模式。剩余碳百分比与剩余质量百分比之间的关系接近1:1，在分解过程中P的总量呈现出淋溶-富集-释放状态。在分解的第一阶段，土壤和上覆水中的养分发生了显著变化。然而，到实验结束时，除了对进行10厘米掩埋处理外，土壤养分的总体变化并不显著。此外，氧化还原电位是不同掩埋深度下凋落物分解过程中的主要因素。本研究表明，沉积物沉积减少了凋落物的质量损失，减缓了N和P的释放，并保留了更多的C，但促进了K的释放。总之，在淹水条件下的凋落物分解过程中，土壤养分的总含量变化不大。然而，凋落物对土壤的作用不止于此。因此，有必要研究水位下降后残留土壤凋落物的持续输出情况，以便进行恢复工作。
