抄録
The amount of litter discharge and its influence on nutrient loads from a Japanese cypress plantation watershed were examined. The temporal changes of litter discharge were controlled mainly by the amount of rainfall. The proportions of litter discharge to litterfall of Japanese cypress and Japanese red pine were 0.18?2.11% and 0.03?1.41%, respectively, from 1999 to 2002. The annual nitrogen, phosphorus, and carbon loads from litter discharge in this period were 0.046?0.800, 0.003?0.057, and 1.9?33.0 kg/ha/year, representing 0.6?5.2% and 3.8?10.1% of the total nitrogen and phosphorus loads, respectively. Nutrient loads were highest in 2001, a rainy year, and the contributions of litter discharge to total nutrient loads were also highest in this period. These results show that nutrient loads from litter discharge have a minor influence on total nutrient loads from this forested watershed in normal years, but play an important role in rainy years.
