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.
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Showing 1 to 20 of 58 for “"nitrogen availability"”.
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Evaluation of nitrogen availability indices
… the reliability of recommendations from three N availability indices and four laboratory methods to measure extractable organic N (EON), and the accuracy and repeatability of the Horiba Cardy Nitrate meter in determining NO$\sb3$-N content in soils and solution.
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Plant nitrogen availability in selected Virginia soils
… incubation procedure as an index of organic N availability. Plant available N was measured by N uptake of successive wheat crops grown in the greenhouse. Multiple linear regression models for different groups of samples were used to determine the contribution of the different soil N fractions …
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Sources of variability in nitrogen availability in Iowa cornfields
… sampling strategies for the late-spring test for nitrogen (N) availability, which is a new management tool that enables site-specific evaluation and adjustment of fertilization practices. One study assessed the importance of windrows of plant residue left by combines as a source of variability in …
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Managing nitrogen availability for increased yield of corn and soybean
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2022-11-11 without embargo terms
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Relationships among Root Traits, Nitrogen Availability, and Mineral-Associated Organic Carbon
… dissertation investigates how plant root traits, nitrogen (N) fertilization, and cover cropping influence soil organic carbon (SOC) and MAOC. In the first chapter, a greenhouse experiment with 30 herbaceous plant species found that non-N-fixing plants exhibited stronger positive correlations with …
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Nitrogen availability and pine seedling growth in organically- amended mine soils
Adequate supply and availability of nitrogen (N) is a major factor hindering successful revegetation of reclaimed surface mines. Because topsoils are often unrecoverable, “topsoil substitutes”, made up of overburden materials devoid of N, are often used on reclaimed surfaces. Four replications of …
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Influence of soil water regime on nitrogen availability and plant competition in wet meadows
… meadows include site hydrology, soil nutrient availability and grazing. Of these, depth and annual variation of the water table has been considered as a primary factor and been frequently used in management decisions. A mechanistic understanding of how water regime influences species …
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The Role of Nitrogen Availability, Hydroperiod and Litter Quality in Root Decomposition Along a Barrier Island Chronosequence
… addressed how hydroperiod, litter quality and nitrogen availability influenced below ground root decay in response to gradients associated with site age and topographic position and in the context of a nitrogen limited ecosystem. Effects on rates of mass loss and nitrogen and phosphorus …
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Interactive effects of hemlock mortality and nitrogen availability on nutrient pools and fluxes in the southern Appalachian Mountains
… (Tsuga canadensis) 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 …
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Controls on terrestrial carbon and nutrient cycling in Arctic permafrost environments
… between environmental conditions, soil nitrogen availability, and greenhouse gas exchange under ambient and experimental conditions. At the Cape Bounty Arctic Watershed Observatory on Melville Island, Nunavut, varying land cover types exist across a naturally occurring moisture gradient, …
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The nitrogen cycle and ecohydrology of seasonally dry grasslands
… of ecosystem traits with the water, carbon, and nitrogen cycles. Observations from a factorial irrigation-fertilization experiment in a seasonally dry annual grassland are combined with a simple ecosystem model to identify relationships between vegetation, nitrogen availability, and hydrology. …
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The Effect of Nitrates, pH, and Dissolved Inorganic Carbon Concentrations on the Extracellular Polysaccharide of Three Strains of Cyanobacteria Belonging to the Family Nostocaceae
… polysaccharides (EPS) in response to carbon and nitrogen availability as well as pH. While the carbohydrate compositions of the glycans produced by the different organisms were indicative of their recent evolutionary divergence, there were measurable differences that were dependent upon growth …
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Interactions, Heterogeneity, and the Determinants of Multispecies Coexistence
… chapter one, I examine how changes in resources (nitrogen availability) and natural enemies (foliar pathogens) modify the mechanisms of plant diversity and composition. To do that, I quantify the intrinsic growth rates and interaction coefficients between eight common Central European perennial …
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Prochlorococcus genetic transformation and genomics of nitrogen metabolism
… gyres where major plant nutrients such as nitrogen (N) and phosphorus (P) are at nanomolar concentrations. Nitrogen availability controls primary productivity in many of these regions. The cellular mechanisms that Prochlorococcus uses to acquire and metabolize nitrogen are thus central to …
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The role of BELL transcription factors in tuber induction of potato (Solanum tuberosum)
… influences such as photoperiod, temperature, and nitrogen availability have long been recognized, the underlying molecular mechanisms are still being uncovered. Given that potato is the fourth most important crop in the world, understanding the regulation of tuber formation is of great importance …
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Physical, genetic, and biochemical analyses of mannityl opine catabolism genes from the Agrobacterium Ti plasmid pTi15955
… is repressed by succinate when ammonium is the nitrogen source. Repression exerted by succinate was relieved when MOP was supplied as sole source of nitrogen. This suggests that genes for opine catabolism encoded by pYDH208 are regulated in part by nitrogen availability.
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Competition For Above And Below Ground Resources Among Annual Species From The Plant To The Field: Quantification Analysis And Modeling
… through a modeling exercise the effects of soil nitrogen and weather on competitive growth of Abutilon theophrasti M. (velvetleaf) and Zea mays L. (maize). For this purpose a mechanistic individual based model was developed, which estimates light interception, photosynthesis, respiration, growth, …
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The lazy root : Will a change in the rainfall regime or increased anthropogenic nitrogen result in an alteration in the competitive balance between trees and grassed in a semi-arid South Africa savanna?
… to determine the effect of increased water and nitrogen availability on root activity of trees and grasses. Pits of 20 x 20 em were dug to a depth of 40 em in plots that were either irrigated with the equivalent of 30 ml of rainfall per month or left without irrigation. This study was performed …
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