Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 29 for “"N dynamics"”.
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Examining the Role of Climate, Carbon and Nitrogen Interactions in the Terrestrial Biosphere
… comprehensive model of terrestrial nitrogen (N) dynamics is developed and coupled with the geographically explicit terrestrial C cycle model of ISAM. Observations from the Long-term Intersite Decomposition Experiment (LIDET) dataset were compiled for the calibration and validation of the …
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Crop Rotations for Sustainable Intensification
… examined how preceding crops influence N dynamics and yield formation. Differences among crop sequences could not be explained solely by total N availability. Non-cereal preceding crops increased both N uptake and grain yield within identical N fertilization treatments, indicating …
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Interactive effects of fire and grazing on soil and forage nitrogen dynamics in a tallgrass prairie
… yet their combined effects on soil nitrogen (N) dynamics and links to forage quality across heterogeneous landscapes remain incompletely resolved. This thesis examined how fire frequency, grazing, and landscape position interact to regulate N cycling, N retention, and plant–soil feedbacks in …
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Sources And Controls Of Reactive Nitrogen Gas Emissions From A Mojave Desert Ecosystem
… our understanding of gaseous nitrogen (N) loss dynamics in arid ecosystems, a process that directly affects longterm N bioavailability and the release of chemically important gas species into the atmosphere. Chapter one focuses on identifying controls over biological sources of reactive N gas …
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Process-based modelling of N losses from terrestrial ecosystems
… thesis studied N fluxes, particularly soil N dynamics, in different ecosystems in relation to interactions between physical and biological processes using a process-based model called the CoupModel. A sub-model implementation of two important processes contributing to nitrogen oxide (NO), N2O, …
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Soil Carbon and Nitrogen Dynamics Across the Hillslope-Riparian Interface in Adjacent Watersheds with Contrasting Cellulosic Biofuel Systems
… properties and selected soil C and nitrogen (N) dynamics among alternative cellulosic biofuel treatments at the Weyerhaeuser Alabama Cellulosic Biofuel Research site in west-central Alabama. Composite soils for characterization, along with forest floor, were collected at year 1 and year 2 after …
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Biochar Effects on Soil Microbial Biomass and Activity
… and their biological effects on soil C and N dynamics.
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Carbon and Nitrogen Dynamics of a Lagoon Salt Marsh in Davenport, California
… There is a clear need for further study of the dynamics of <em>Typha</em> invasion and its effects on salt marsh C and N dynamics.</p> <p>Hydrology, which controls oxidized versus reduced soil conditions is a clear driver of C and N dynamics in these salt marshes. The 32-day incubation revealed …
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Linking Carbon, Nitrogen, And Calcium Cycling In Northeastern U.S. Forests
… long-term effects of liming on ecosystem C and N dynamics. Twenty years after lime addition, there was no evidence of a tree response. Within the forest floor, C and N stocks in limed soils were double that found in controls. I observed reductions in both soil basal respiration and net N …
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The Effect of Soil Organic Carbon Amendments on Nitrogen Dynamics after Broccoli (Brassica oleracea L. var. Italica) Production
… OCA on subsequent crop production. Therefore, N dynamics were evaluated via incubation, field, and tracer studies after broccoli (var. italica) harvest with soil OCAs. In the 56 d laboratory trial, broccoli crop residue or fertilizer-N was incorporated with either wheat straw, yard waste, or used …
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Plant species effects on soil organic matter turnover and nutrient release in forests and grasslands
… feedbacks between plant species and ecosystem dynamics have been demonstrated in a variety of terrestrial ecosystems, little research has examined the mechanistic relationship between plant species characteristics, the formation and turnover of soil carbon and nitrogen pools, and ecosystem …
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Effects of plant invasions on ecosystem processes: Linking above- and below-ground resource-use strategies of native and invasive species in Eastern U.S. forests
… resource-use strategies and soil nitrogen (N) dynamics for multiple native and non-native forest understory species in the Eastern U.S. to better understand invader impacts on ecosystem processes. In the first study, performed in a common garden, I examined the linkage between above- and …
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Interactive effects of hemlock mortality and nitrogen availability on nutrient pools and fluxes in the southern Appalachian Mountains
… exerts strong control on nitrogen (N) dynamics, and its loss due to infestation by the hemlock woolly adelgid (Adelges tsugae) is expected to affect nutrient dynamics in impacted stands. I evaluated the potential for variation in N availability to influence the magnitude of effects of …
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Biogeochemical effects of an invasive grass across a land-use gradient: linking alterations of nitrogen cycling to depleted soil carbon pools
… effects of M. vimineum on belowground C and N dynamics and enzyme activities in forests across a 45-km urban-rural gradient in Southern Appalachia, USA. Consistent with previous reports, invasion was associated with depleted soil organic C pools and increased N availability. Structural equation …
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Relationships among Root Traits, Nitrogen Availability, and Mineral-Associated Organic Carbon
… root morphology, environmental factors, and C/N dynamics is necessary to develop more resilient agroecosystems capable of mitigating C losses and improving long-term soil health.
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Crop modeling for assessing and mitigating the impacts of extreme climatic events on the US agriculture system
… captures the subfield variability of N dynamics and gives reasonable spatially explicit sidedress N recommendations. The prescription enhances zones with high yield potentials, while prevents over-fertilization at zones with low yield potentials.</p>
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Unraveling an uncertain future for the Great Basin: how climate, grass invasion, and wildfire interact to drive ecosystem function
… dry conditions. When combined with seasonal dynamics and annual grass phenology, these mechanisms may provide cheatgrass with greater access to soil N compared to native species. In chapter two, I used simulation modeling to mechanistically test the effects of changing precipitation regimes …
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Soil chemistry and ecology on a restoration trajectory of a coastal sandplain forest, Punakaiki, New Zealand
… soil chemical properties, including nitrogen (N) dynamics. It was found that two native species, Kunzea robusta and Olearia paniculata, may have the potential to ameliorate concerns associated with nitrate leaching and nitrous oxide production. Restored vegetation at the study site modified the …
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Switchgrass as an Energy Crop: Fertilization, Cultivar, and Cutting Management
… at Orange and Blacksburg, VA to examine N dynamics. For the 3-yr study, N fertilizer was applied once in May 2001 at 0, 90, 180, or 270 kg N ha-1. Switchgrass was harvested once (early November) in 2001 and twice (early July and early November) in 2002 and 2003. Tissue, root, and soil …
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