沙质海岸不同林分凋落物的水文特性及其对土壤持水的影响

Litter Water Retention Characteristics and Impacts on Soil Water Holding Capacity of Different Sandy Coastal Forests

摘要:

为探究木麻黄作为沿海防护林的主要树种对改善和维护生态系统水源涵养功能的重要性，该研究以木麻黄(Casuarina equisetifolia)纯林、桉树(Eucalyptus urophylla)纯林、针阔混交林和天然林4种林分的凋落物和土壤为研究对象，测定其水文特性及相关理化性质。结果表明，木麻黄纯林可在短时间内积累显著高于其他林分的凋落物量[(36.83±1.11) t/hm²]，是其他林分的2~3倍；能够在同等时间内吸收更多水，其饱和持水量可达其他林分的2~3倍[(102±2.15) t/hm²]。同时，4种林分凋落物在各时间段内的平均失水速率相近，这表明吸水量更高的林分能够拥有更好的持水效应。此外，土壤含水量与凋落物的饱和持水率、有效拦蓄率、最大拦蓄率和碳氮比呈现显著正相关关系，说明凋落物的水文特性和化学性质对土壤水分保持具有显著的影响。木麻黄纯林凋落物在沙质海岸的水分保持能力和生态系统涵养水源功能提升方面表现出显著优势，对提升生态系统水文功能有重要意义。该研究为沙质海岸区域的生态恢复和持续管理提供了重要的理论依据和实践参考，同时为未来的沿海防护林管理策略和生态系统服务功能优化提供了科学指导。

Abstract:

To explore the significance of Casuarina equisetifolia as a major tree species in coastal protective forests for improving and maintaining the water conservation function of the ecosystem, this study took the litter and soil of four types of forests, namely pure C. equisetifolia forests, pure Eucalyptus urophylla forests, mixed coniferous and broad-leaved forests, and natural forests, as the research objects, and measured their hydrological characteristics and related physical and chemical properties. The results showed that pure C. equisetifolia forests could accumulate significantly more litter than other forests in a short period of time [(36.83±1.11) t/hm²], which was 2 to 3 times that of other forests; they could absorb more water in the same period of time, and their saturated water holding capacity could reach 2 to 3 times that of other forests [(102±2.15) t/hm²]. At the same time, the average water loss rates of the litter of the four types of forests in each time period were similar, indicating that forests with higher water absorption capacity could have better water retention effects. In addition, soil moisture content was significantly positively correlated with the saturated water holding capacity, effective water retention rate, maximum water retention rate and carbon-nitrogen ratio of the litter, indicating that the hydrological characteristics and chemical properties of the litter had a significant impact on soil moisture retention. Pure C. equisetifolia forests showed significant advantages in water retention capacity and ecosystem water conservation function improvement in sandy coastal areas, which was of great significance for improving the hydrological function of the ecosystem. This study provided important theoretical basis and practical reference for the ecological restoration and sustainable management of sandy coastal areas, and at the same time provided scientific guidance for the future management strategies of coastal protective forests and the optimization of ecosystem service functions.