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The American cranberry (Vaccinium macrocarpon Ait.) is an important part of the cultural heritage and economy of Southeastern Massachusetts, yet water quality concerns and wetland protection laws challenge its commercial production. Here, we report inputs and outputs of water, nitrogen (N), and phosphorus (P) for a 2.12‐ha cranberry bed over a 2‐year period from 2013 to 2015. Water‐budget analysis indicated that precipitation contributed 40%, floodwater 37%, irrigation 15%, and groundwater 8% of water inputs to the cranberry bed. Minor annual variation in surface water discharge (~90 mm·year?1 or 3%) contrasted with large decreases in net (= outputs ? inputs) nutrient export, from 16.2 to 9.1 kg N·ha?1·year?1 for total (dissolved + suspended particulate) nitrogen (TN) and from 3.34 to 1.47 kg P·ha?1·year?1 for total phosphorus (TP) between Years 1 and 2. Annual variation in net TN and TP export was tied to decreases in spring and summer nutrient export and controlled by the combined effects of fertilizer management, soil biogeochemistry, and hydrology. The relatively high spring TN export in Year 1 was associated with coincident increases in soil temperature and rainfall. A second factor was the timing of fertilizer application, which occurred 1 day prior to a major summer storm (i.e., third largest daily rainfall since 1926) and was responsible for up to 15% and 9% of the Year 1 TN and TP export, respectively. Nutrient budgets, which balanced water and fertilizer inputs with water, fruit, and vegetative outputs, were consistent with the burial of 21.6 kg N·ha?1·year?1 and 7.27 kg P·ha?1·year?1. Field measurements indicated that burial would increase TN and TP in the shallow (0–5 cm) rooting zone by 14% and 6%, respectively, which seemed plausible based on the relatively young age of the bed (4–5 years) and new root growth patterns in Vaccinium plants. 相似文献
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A graphic review of the growth and decay of population cohorts 总被引：1，自引：0，他引：1
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In this paper we attempt to reconcile seemingly contradictory research concerning the existence of an El-Niño Southern Oscillation (ENSO) signal in precipitation records from the Gulf of Alaska region. A number of studies based on records from primarily coastal stations and the mass balance of low elevation glaciers suggest there is at best a weak relationship between ENSO and precipitation anomalies in the region. In contrast, an analysis of an ice core extracted from a high elevation site on Mount Logan in the region indicates that a statistically significant ENSO signal exists in its annual snow accumulation time series on both inter-annual and inter-decadal time scales. The ENSO signal in the region is expressed through an atmospheric teleconnection known as the Pacific North America pattern. We show that a statistically significant enhancement in the atmospheric moisture transport into the North Pacific and western North America is associated with the warm phase of ENSO. The maximum transport does not occur at the surface but rather in the lower to middle troposphere. We argue that the high elevation of the Mount Logan site allows it to preferentially sample the vertically distributed moisture transport anomaly associated with warm ENSO events. This study serves to highlight the wealth of information on teleconnection patterns that may be contained in paleoclimate data from mountainous regions. 相似文献
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