题目 Title
Effect of soil moisture on the multi-component decomposition of wetland macrophytes.
期刊 Journal
Hydrobiologia (IF=2.822)
作者 Author
Xu S; He GJ; Fang HW; Liu SW; Bai S
摘要 Abstract
The effect of soil moisture on plant litter decomposition is one of the major focuses of decomposition research. In this study, 150-day laboratory experiments were conducted with the simulated soil environment under different moisture levels. Three macrophytes, Phragmites australis, Miscanthus lutarioriparius, and Carex cinerascens, were selected. The dry biomass weight, and nutrient concentrations of plant samples were measured during the experiment, and a modified bi-exponential formula was used to investigate the effects of soil moisture on plant decomposition under non-submerged conditions. The litter decomposition process is considered as the simultaneous exponential decomposition of labile and refractory components. The relationship between the decomposition rates of the two components and soil moisture was found to be exponential. The results showed that the modified formula with moisture factor agreed well with the dry weight data (R2 > 0.97). The mass fractions of the labile component were 5.9%, 11.3%, and 6.7% for P. australis, M. lutarioriparius, and C. cinerascens, respectively. As moisture increased from 50 to 90%, the decomposition rate k1 of labile part increased from 0.05 to 0.12 day-1, and k2 of refractory part increased from about 0.0007 to 0.006 day-1. Higher quality plant (with high N content and low C content) decomposed faster. The effect of different moisture levels on the microbial community in the experiment was not significant. Furthermore, a longer humidification time in one cycle can promote the decomposition of both parts. The proposed bi-exponential formula of plant decomposition can be used to estimate vegetation decomposition in alternating wetting and drying surface waters.
简介 Brief introduction
为分析土壤湿度对植物凋落物分解的影响，本研究选择了三种植物：芦苇（Phragmites australis）、南荻（Miscanthus lutarioriparius）和灰化薹草（Carex cinerascens），在不同湿度条件下模拟土壤环境并进行了为期150天的实验,过程中测量植物样品的干生物质重量和营养物质浓度。凋落物的分解过程可认为是易分解成分和难分解成分同时独立分解的叠加，实验发现两种成分的分解率与土壤湿度间的关系为指数关系，因此可使用修正后的双指数公式分析土壤湿度对非淹没条件下植物分解的影响。结果表明：不同湿度条件对微生物群落的影响并不显著；高质量植物（N含量高，C含量低）分解更快；湿度修正后的公式与干重数据吻合良好（R2>0.97），其中芦苇、南荻和灰化薹草易分解成分的质量分数分别为5.9%、11.3%和6.7%，当湿度从50％增加到90％时，易分解成分的分解率提高约140%，难分解成分的分解率提高约857%；在一个周期内较长的加湿时间能够促进两类成分的分解。本研究所提出的植物分解双指数公式可用于估计地表水干湿循环交替时的植被分解情况。
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