Abstract:

This study scrutinizes the hydrological benefits conferred by forest litter and soil across various stand types in Yunyong Forest Farm, Foshan City, Guangdong Province, through employing field surveys and laboratory water retention tests. Specifically, the research subjects encompasses Pinus massoniana pure forest, Pinus caribaea pure forest, Cunninghamia lanceolata pure forest, and a mixed forest of Chinese fir. The findings reveal that litter biomass across the four stand types ranged from 4.42 to 6.72 t∙hm⁻², with the mixed Chinese fir forest exhibiting the highest amount and the Masson pine forest having the lowest values. Notably, the litter’s semi-decomposed layer harbored a greater mass than its undecomposed counterpart in each forest type. The mixed Chinese fir forest, in comparison to its monoculture counterpart, had an increase of 4.83% and 13.57% in maximum water-holding capacity and effective retention capacity of litter, respectively. Among the three coniferous forests, the Chinese fir forest had the highest maximum water-holding capacity and effective water storage capacity (7.12 t∙hm⁻² and 6.00 t∙hm⁻², respectively). These capacities were significantly positively correlated with litter thickness and biomass (p<0.05). Moreover, the saturated water-holding capacity, capillary water-holding capacity, and non-capillary water-holding capacity of soil in the Caribbean pine forest were 1.18−1.44 times higher than the other three forest types. The saturated water-holding capacity, capillary water-holding capacity, and non-capillary water-holding capacity of soil in the mixed forest increased by 10.79, 3.94, and 6.84 t∙hm⁻² compared to the Chinese fir forest. The saturated water-holding capacity and capillary water-holding capacity were significantly correlated with total soil porosity, capillary porosity, bulk density, and organic carbon content (p<0.05), while non-capillary water-holding capacity was mainly related to non-capillary porosity and bulk density of soil (p<0.05). Redundancy analysis elucidates that soil porosity and mass fraction of organic carbon are pivotal in modulating soil water retention across differing stand types, with litter thickness and mass fraction of organic carbon being the salient factors determining the disparities in litter water retention capabilities. The comprehensive water conservation capacity ranking of the four forest types was as follows: mixed Chinese fir forest>Caribbean pine forest>Chinese fir forest>Masson pine forest. Consequently, coniferous mixed forests emerge as superior hydrological assets for the region, with Caribbean pine forest being the most effective among the monocultures. It is recommended that Caribbean pine forest be considered a prime candidate in future afforestation projects for water conservation.

Key words: different stand types, coniferous pure forest, mixed forest, litter, soil, water conservation capacity

摘要：

以广东省佛山市云勇林场的马尾松纯林（Pinus massoniana）、加勒比松纯林（Pinus caribaea）、杉木纯林（Cunninghamia lanceolata）和杉阔混交林为研究对象，通过野外调查和室内浸泡法，探究不同林分类型凋落物和土壤的水源涵养能力。结果表明，1）4种林分的凋落物总量介于4.42—6.72 t∙hm⁻²之间，其中杉阔混交林最大，马尾松林最小，且各林分半分解层的凋落物总量均大于未分解层。相比于杉木纯林，杉阔混交林凋落物最大持水量和有效拦蓄量分别提高了4.83%和13.57%。在3种针叶林中，杉木林的最大持水量和有效拦蓄量最大（7.12、6.00 t∙hm⁻²）。凋落物最大持水量、有效拦蓄量与凋落物厚度、现存量均为显著正相关（p<0.05）。2）加勒比松林的土壤饱和持水量、毛管持水量和非毛管持水量分别是其他3种林分的1.18—1.44倍。杉阔混交林的土壤饱和持水量、毛管持水量和非毛管持水量相比于杉木林分别增加了10.79、3.94、6.84 t∙hm⁻²。土壤饱和持水量和毛管持水量主要与土壤总孔隙度、毛管孔隙度、容重和有机碳质量分数显著相关（p<0.05），土壤非毛管持水量主要与土壤非毛管孔隙度和容重显著相关（p<0.05）。3）冗余分析表明，土壤孔隙度和有机碳质量分数对不同林分类型土壤持水能力的变化具有重要影响，而凋落物厚度和有机碳质量分数是导致不同林分类型凋落物持水能力产生差异的关键因素。4个林分的综合水源涵养能力大小排序依次为：杉阔混交林>加勒比松林>杉木林>马尾松林。针阔混交林在水源涵养方面是研究区域的理想选择，在3种针叶纯林中，加勒比松林的水源涵养能力表现最佳。建议未来在营建水源涵养林时，可以考虑将加勒比松作为混交树种之一。

关键词: 不同林分类型, 针叶纯林, 混交林, 凋落物, 土壤, 水源涵养能力