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Full-Text Articles in Physical Sciences and Mathematics
Global And Regional Assessments Of Unsustainable Groundwater Use In Irrigated Agriculture, Danielle S. Grogan
Global And Regional Assessments Of Unsustainable Groundwater Use In Irrigated Agriculture, Danielle S. Grogan
Doctoral Dissertations
Groundwater is an essential input to agriculture world-wide, but it is clear that current rates of groundwater use are unsustainable in the long term. This dissertation assesses both current use of groundwater for country- to global-scale agriculture, and looks at the future of groundwater. The focus is on 1) quantifying food directly produced as a result of groundwater use across spatially-varying agricultural systems, 2) projecting future groundwater demands with consideration of climate change and human decision-making, and 3) understanding the system dynamics of groundwater re-use through surface water systems. All three are addressed using a process-based model designed to simulate …
Mechanisms Of Nutrient Limitation And Nutrient Acquisition In Managed And Unmanaged Forest Ecosystems, Matthew A. Vadeboncoeur
Mechanisms Of Nutrient Limitation And Nutrient Acquisition In Managed And Unmanaged Forest Ecosystems, Matthew A. Vadeboncoeur
Doctoral Dissertations
Understanding the interactions between global change, human and natural disturbances, and other factors on biogeochemical processes in forests is necessary to ensure the sustainability of forest management. Here I report the results of several investigations into nutrient acquisition processes in the forests of New Hampshire. I begin with a meta-analysis of fertilization studies showing that phosphorus (P) and calcium (Ca) as well as nitrogen (N) may limit primary production in deciduous forests of the region. Because these limiting nutrients are all removed from the ecosystem when trees are harvested, I compared nutrient budgets under a range of harvesting scenarios with …