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 15 of 15 for “"N-demand"”.
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Study of nitrogen limitation and seed nitrogen sources for historical and modern genotypes in soybean
… between seed yield and nitrogen (N) demand are reported in the scientific literature. Main sources of N to the plant are the biological N fixation (BNF) and the soil mineralization processes. On overall, only 50-60% of soybean N demand is met by the BNF process. An unanswered …
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Estimating Nitrogen Fixation Rates, Importance, and Short-Term Efficiency in Small, Temperate Reservoirs Using Delta15N Techniques
… fixation rates and importance to autotrophic N demand and zooplankton N assimilation. Results of the mesocosm experiment indicated that N2 fixation was increased at low N:P supply under high P. However, N2 fixation was inefficient at alleviating N limitation when fixed N was the primary source …
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Evaluating the importance of root abscission versus efflux to plant N-loss: consequences for plant N-isotope composition
… When the N supply matched the plant N demand, as determined by the relative growth rate, there was no discrimination between plant and source δ¹⁵N. N-loss here, although negligible, was in the organic form, which implies root abscission. By contrast, when N supply exceeded plant N …
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Investigating Structure and Function of Rhizosphere Associated Microbial Communities in Natural and Managed Plant Systems
… growth are associated with increased plant N-demand and supportive of bacteria with greater rates of N2-fixation in the rhizosphere. Another crucial outcome of the thesis is a better description of the core and cultivar-specific taxa that comprise the switchgrass root-zone associated …
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Genetics by Nutrient Availability Interactions on Short-term Carbon Pools and Fluxes in Young Pinus taeda Plantations
… more favorable canopy architecture and lower N demand. Our results clearly show that contrasting ideotypes have the potential to respond differently to differences in nutrient availability in terms of biomass partitioning, leaf physiology, and leaf biochemistry (Chapter 3). Both experiments …
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Estimating Soil Nitrogen Supply and Fertilizer Needs for Short-Rotation Woody Crops
… 2) determine soil N supply, plant N demand, foliar N resorption, and soil and fertilizer uptake efficiencies, and 3) test a simple N supply model. In order to expand the findings to the range of sweetgum site types, the study objectives were also to 4) evaluate rapid methods for …
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Nitrogen spiraling in stream ecosystems spanning a gradient of chronic nitrogen loading
… production (GPP) accounted for most NO3-N demand. Uptake of NO3-N was also related to GPP but was limited by N availability when N concentrations were low. A combination of GPP and NO3-N explained 80% of the variance in uptake. In chapter 3, I conducted a series of short-term nutrient …
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Organic nitrogen uptake by marine algae: consequences for marine ecosystem functioning and biodiversity
… of ARG along with the cosmopolitan E. huxleyi; N-demand estimates, based on the molar concentration of N-ARG consumed, correlated with the final cell density, indicating that the species did not develop on inorganic N produced from ARG mineralisation, but directly on the ON substrate. Since A. …
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Potential enzyme activities in soils as affected by perennial cropping and nitrogen rates in central Iowa
… PrF and CS systems was likely due to microbial N demand. Additionally, I observed that the substrate concentration needed to achieve Vmax exceeded the substrate concentrations typically employed in many other enzyme studies, suggesting the necessity to determine a substrate saturation curve for …
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The response of symbiotic performance, growth and yield of chickpea (Cicer arietinum L. ) genotypes to phosphorus fertilizer rates and rhizobial inoculation
… still without enough N concentration to meet N demand. It is therefore important that other alternatives that can help improve the N status of soils be explored. The shoot δ13C is an indicator of WUE in C3 plants. However, shoot-WUE is affected by a variety of factors including genotypes, …
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Intercropping dynamics in a perennial Kernza cropping system
… physiologically determined rates and timing of N demand, mediating N mineralization and uptake rates. These findings enhanced our understanding of Kernza-alfalfa N dynamics, including the benefit of ground cover in providing this essential nutrient to perennial cereals, compared to synthetic …
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Evaluation of nitrogen management strategies and policies using high-throughput crop simulations
… and crop processes, matching N supply and crop N demand to minimize N losses is difficult to achieve. Sub-applications result in low yields, and over-applications result in environmental losses that harm water quality. These difficulties create what is known as the Nitrogen challenge. This …
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Estimation and mitigation assessment of N₂O emission and nitrate leaching in a mountainous catchment in South Korea using the LandscapeDNDC model
… induced from higher fertilization than crop N demand is highly susceptible to loss as N2O emission and nitrate leaching during heavy rainfall events in the monsoon season. Intensive farming conducted in the Haean catchment of South Korea has received much attention due to its geographical …
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The potential implications of bioenergy crop production for water and energy balance and carbon and nitrogen dynamics in the United States
… biomass productivity in tandem with decreased demand for land and water on a per unit of ethanol production. These regions, primarily occupied by crops and forests, include the southern Midwest for Miscanthus, the northern Midwest for Cave-in-Rock, and the southern US for Alamo. However, the …