We evaluated the phenology and litterfall dynamics of the mangrove Bruguiera gymnorrhiza（L.）Lamk along the Okukubi River, Okinawa Island, Japan.Over 3 years, this species showed the highest litterfall of leaves and ...We evaluated the phenology and litterfall dynamics of the mangrove Bruguiera gymnorrhiza（L.）Lamk along the Okukubi River, Okinawa Island, Japan.Over 3 years, this species showed the highest litterfall of leaves and stipules in summer and the lowest litterfall in winter. From Kendall＇s coefficient of concordance, the monthly changes in leaf, stipule, and branch were strongly and significantly concordant among years. Leaf and stipule litterfall could be governed by monthly maximum wind speed, monthly day length, and monthly mean air temperature. Branch litterfall depended on monthly maximum wind speed and monthly rainfall, and increased exponentially with increasing monthly maximum wind speed. Mean total litterfall was 11.8 Mg ha^（-1）yr^（-1）, with the largest component being leaf litterfall（65.8 %）. Annual leaf litterfall per plot was almost constant regardless of the tree density of the plot. Mean leaf longevity was 18 months.Flower and mature propagule litterfall might be influenced by monthly mean air temperature, monthly day length and monthly mean air temperature. The average development periods from flower buds to flowers and flower buds to mature propagules were 1 and 8 months, respectively.Except for leaf and branch, all vegetative and reproductive organ litterfall had clear annual cycles. B. gymnorrhiza showed a positive correlation between leaf production and reproductive organ production.展开更多
With the excess use of nitrogen, a number of global and regional factors need to be addressed. Nitrate contamination of agricultural water leads to a number of environmental problems. During the twentieth century, the...With the excess use of nitrogen, a number of global and regional factors need to be addressed. Nitrate contamination of agricultural water leads to a number of environmental problems. During the twentieth century, the human being has used increasingly more reactive nitrogen, intentionally as fertilizer. The revolution in agricultural production is possibly increase by the use of nitrogen fertilizers. The inorganic nitrogen fertilizers are an essential input for maintaining high crop yield. This article discusses the origin and role of nitrogen in the environment. The potential and use of nitrogen as fertilizer for groundwater and surface water quality resources in agricultural purposes are discussed.展开更多
基金supported by a Grant-in-Aid for Scientific Research(No.23380094)from the Ministry of Education,Culture,Sport,Science and Technology,Japan
文摘We evaluated the phenology and litterfall dynamics of the mangrove Bruguiera gymnorrhiza（L.）Lamk along the Okukubi River, Okinawa Island, Japan.Over 3 years, this species showed the highest litterfall of leaves and stipules in summer and the lowest litterfall in winter. From Kendall＇s coefficient of concordance, the monthly changes in leaf, stipule, and branch were strongly and significantly concordant among years. Leaf and stipule litterfall could be governed by monthly maximum wind speed, monthly day length, and monthly mean air temperature. Branch litterfall depended on monthly maximum wind speed and monthly rainfall, and increased exponentially with increasing monthly maximum wind speed. Mean total litterfall was 11.8 Mg ha^（-1）yr^（-1）, with the largest component being leaf litterfall（65.8 %）. Annual leaf litterfall per plot was almost constant regardless of the tree density of the plot. Mean leaf longevity was 18 months.Flower and mature propagule litterfall might be influenced by monthly mean air temperature, monthly day length and monthly mean air temperature. The average development periods from flower buds to flowers and flower buds to mature propagules were 1 and 8 months, respectively.Except for leaf and branch, all vegetative and reproductive organ litterfall had clear annual cycles. B. gymnorrhiza showed a positive correlation between leaf production and reproductive organ production.
文摘With the excess use of nitrogen, a number of global and regional factors need to be addressed. Nitrate contamination of agricultural water leads to a number of environmental problems. During the twentieth century, the human being has used increasingly more reactive nitrogen, intentionally as fertilizer. The revolution in agricultural production is possibly increase by the use of nitrogen fertilizers. The inorganic nitrogen fertilizers are an essential input for maintaining high crop yield. This article discusses the origin and role of nitrogen in the environment. The potential and use of nitrogen as fertilizer for groundwater and surface water quality resources in agricultural purposes are discussed.
