| Summary: | 碩士 === 國立中興大學 === 水土保持學系 === 89 === Seventeen coastal windbreak forest soils located along the Western Taiwan were sampled to study the mechanism of water repellency and its effect on the nutrient cycles of the forests. Both climate zone and tree species show insignificant correlation with water repellency of the forests. To unveil water repellency of a forestland, the hydrophobic phenomenon in litter and/or soil layers of the forestland should be discussed separately. Pure stand usually has a significant development of fungal filaments in the litter layer, which decreases infiltration rate and affects the distribution of nutrients and hydrophobic substances in the soil layers. An accumulation effect of nutrient, especially available phosphorus can be detected at the topsoil of pure stand. Mixed stands having the properties of decomposable litter layer show significant water-repellent strength and depth in soil layers compare to the pure stand. However, there is no significant relationship between water-repellent strength and nutrient distribution in the soil layers of mixed stand. This implies that no nutrient accumulation problem occurred in the mixed forest due to soil water repellency.
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