The soils of southern Guam are formed from very deep;well-drained Saprolite derived from volcanic based tuff and tuff breccias.These soils suffer severe erosion as the result of rapid overland flow,wind and intensive ...The soils of southern Guam are formed from very deep;well-drained Saprolite derived from volcanic based tuff and tuff breccias.These soils suffer severe erosion as the result of rapid overland flow,wind and intensive rain events typical of southern Guam.An integrated approach to control the accelerated soil erosion was designed to include conservation tillage,crop rotation with leguminous plant,and residue management for soil surface cover.The objectives of this study are;1)to evaluate the use of crop rotation and tillage management for increasing organic-matter content to improve the overall quality of these severely eroded soils,2)to evaluate the effect of conservation practices on harvested yield and crop productivity of these eroded soils and,3)to assess the effects of conservation techniques including no-tillage systems on water runoff and infiltration.This paper discusses the effect of conservation strategies and techniques on these severely eroded soils of southern Guam.展开更多
By decomposing outgoing Iongwave radiation through empirical orthogonal function （EOF） analysis, the authors identify two anomalous convective systems in the tropical western Pacific. Besides the classical convectiv...By decomposing outgoing Iongwave radiation through empirical orthogonal function （EOF） analysis, the authors identify two anomalous convective systems in the tropical western Pacific. Besides the classical convective system near the Philippines （PC）, there is another convective system near the Federated States of Micronesia （MC）. As the first EOF component in this region, the variance explained by MC is higher than that by PC. Both MC and PC are regulated by the tropical sea surface temperature （SST） anomalies. While PC is associated with an El Ni^o event, MC is correlated with SST anomalies in the central and eastern Pacific during summer. It is also found that the East Asian summer monsoon （EASM） is influenced by these two convective systems. In general, enhanced （suppressed） convection corresponds to an eastwards （westwards） western Pacific subtropical high with weak （strong） intensity. Besides, the summer monsoon rainfall from the Yangtze River basin to Japan tends to increase （decrease） when PC is suppressed （enhanced）. By comparison, the influence of MC is generally weak, with vague signals in the East Asian continent. Moreover, the influence of suppressed convection on the EASM is more significant than that of enhanced convection.展开更多
Talakhaya watershed in Rota is identified as a Coral Reef Management Priority site for CNMI (Com-monwealth of Northern Mariana Islands). In 2010 federal and jurisdictional partners developed a Con-servation Action Pla...Talakhaya watershed in Rota is identified as a Coral Reef Management Priority site for CNMI (Com-monwealth of Northern Mariana Islands). In 2010 federal and jurisdictional partners developed a Con-servation Action Plan (CAP) for the Talakhaya Watershed. The goal of this initial Watershed Soil Loss Assessment therefore, was to assist in evaluating the re-vegetation objectives of 'Mitigating Sediment Load' in the Talakhaya watershed by making a thorough characterization of its main river systems. The objectives of this project were to reach those goals by measuring the hydrological parameters following the installation and the use of water meters, barometric level loggers, turbidity meters and rain gauges. The water flow as well as the turbidity level of each stream leading to the ocean from the Talakhaya Watershed was measured and sedimentation level was assessed accordingly. The results from the monitoring of the watershed conducted during the project timeline reported here show that all four rivers under study have statistically different stage-discharge curves. The river's relationship between time and turbidity also vary especially in the summer months of the first-year observations. Linear and convex polynomial relationships were sometimes observed in the different rainfall groupings for the four river systems, however relationships were often not significant. This-being-said, Quantile Regressions suggest that when data from all four river systems are combined for cases where there is some de-tectable rainfall, a maximum possible turbidity level can be defined.展开更多
文摘The soils of southern Guam are formed from very deep;well-drained Saprolite derived from volcanic based tuff and tuff breccias.These soils suffer severe erosion as the result of rapid overland flow,wind and intensive rain events typical of southern Guam.An integrated approach to control the accelerated soil erosion was designed to include conservation tillage,crop rotation with leguminous plant,and residue management for soil surface cover.The objectives of this study are;1)to evaluate the use of crop rotation and tillage management for increasing organic-matter content to improve the overall quality of these severely eroded soils,2)to evaluate the effect of conservation practices on harvested yield and crop productivity of these eroded soils and,3)to assess the effects of conservation techniques including no-tillage systems on water runoff and infiltration.This paper discusses the effect of conservation strategies and techniques on these severely eroded soils of southern Guam.
基金supported by the National Natural Science Foundation of China[grant number 41475052]
文摘By decomposing outgoing Iongwave radiation through empirical orthogonal function （EOF） analysis, the authors identify two anomalous convective systems in the tropical western Pacific. Besides the classical convective system near the Philippines （PC）, there is another convective system near the Federated States of Micronesia （MC）. As the first EOF component in this region, the variance explained by MC is higher than that by PC. Both MC and PC are regulated by the tropical sea surface temperature （SST） anomalies. While PC is associated with an El Ni^o event, MC is correlated with SST anomalies in the central and eastern Pacific during summer. It is also found that the East Asian summer monsoon （EASM） is influenced by these two convective systems. In general, enhanced （suppressed） convection corresponds to an eastwards （westwards） western Pacific subtropical high with weak （strong） intensity. Besides, the summer monsoon rainfall from the Yangtze River basin to Japan tends to increase （decrease） when PC is suppressed （enhanced）. By comparison, the influence of MC is generally weak, with vague signals in the East Asian continent. Moreover, the influence of suppressed convection on the EASM is more significant than that of enhanced convection.
文摘Talakhaya watershed in Rota is identified as a Coral Reef Management Priority site for CNMI (Com-monwealth of Northern Mariana Islands). In 2010 federal and jurisdictional partners developed a Con-servation Action Plan (CAP) for the Talakhaya Watershed. The goal of this initial Watershed Soil Loss Assessment therefore, was to assist in evaluating the re-vegetation objectives of 'Mitigating Sediment Load' in the Talakhaya watershed by making a thorough characterization of its main river systems. The objectives of this project were to reach those goals by measuring the hydrological parameters following the installation and the use of water meters, barometric level loggers, turbidity meters and rain gauges. The water flow as well as the turbidity level of each stream leading to the ocean from the Talakhaya Watershed was measured and sedimentation level was assessed accordingly. The results from the monitoring of the watershed conducted during the project timeline reported here show that all four rivers under study have statistically different stage-discharge curves. The river's relationship between time and turbidity also vary especially in the summer months of the first-year observations. Linear and convex polynomial relationships were sometimes observed in the different rainfall groupings for the four river systems, however relationships were often not significant. This-being-said, Quantile Regressions suggest that when data from all four river systems are combined for cases where there is some de-tectable rainfall, a maximum possible turbidity level can be defined.
