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Articles 1 - 9 of 9
Full-Text Articles in Life Sciences
A Study Of Short-Season Winter Cover Crops For Organic High Tunnel Production Systems, Luke Riley Freeman
A Study Of Short-Season Winter Cover Crops For Organic High Tunnel Production Systems, Luke Riley Freeman
Graduate Theses and Dissertations
This two-year study investigated short-season winter cover crops to improve soil quality and growth of subsequent vegetable crops in an organic high tunnel production system. Five winter cover crop treatments including a nontreated control, Austrian winter peas (Pisum arvense), bell beans (Vicia faba), mustard (Brassica juncea cv. Kodiak), and Daikon radish (Raphanus sativus var. longipinnatus) were grown in a high tunnel in a randomized complete block design from mid-November to mid-March, mowed and incorporated into the soil, and followed by a succession of vegetable crops including tomato (Lycopersicon lycopersicum, cv. ‘Plum Dandy’) and broccoli (Brassica oleracea var. italica, cv. ‘Bay …
Willingness To Pay For Irrigation Water Under Scarcity Conditions, Tyler Robert Knapp
Willingness To Pay For Irrigation Water Under Scarcity Conditions, Tyler Robert Knapp
Graduate Theses and Dissertations
Reliance of Arkansas agricultural producers on groundwater for irrigation has led to depletion of the Mississippi River Valley alluvial aquifer. Without intervention, consequences include insufficient groundwater to meet irrigation demand as well as drawdown of the deeper Sparta Aquifer, upon which communities in eastern Arkansas rely for non-agricultural use. Among proposed solutions to combat groundwater decline is the construction of off-farm surface water infrastructure to meet the irrigation needs of producers. Despite the importance of irrigated agriculture to Arkansas, there is little know about the economic value of irrigation water to producers. Thus, we implement a double-bounded dichotomous choice contingent …
Migration Ecology Of American Woodcock (Scolopax Minor), Joseph Daniel Moore
Migration Ecology Of American Woodcock (Scolopax Minor), Joseph Daniel Moore
Graduate Theses and Dissertations
Improving the understanding of American woodcock (Scolopax minor) migration ecology has been identified as a priority information need for woodcock management. Developments in remote tracking technology and analytical techniques present an opportunity to gain insight into woodcock migratory connectivity and migration phenology and to evaluate the degree in which the current two-region (Eastern and Central) basis for woodcock management represents migratory movements. To analyze woodcock migration using band return records, I excluded observations that took place during the migratory period. Using this dataset, 17.9% of records showed crossover between management regions, higher than the < 5% crossover found in studies including non-migratory band returns. During autumn migration, woodcock from the Central Region largely migrated to destinations within the Central Region, whereas woodcock from the Eastern Region migrated to destinations across their wintering range, mixing with individuals from the Central Region. Between 2013 and 2016, I deployed 75 satellite transmitters on woodcock. I tracked the migration paths of 61 woodcock and documented 88 woodcock migrations. Average migration duration was longer during spring migration (53 days) than during autumn migration (31 days) because woodcock made a higher number of close-together migratory stopovers, not because woodcock stayed at individual stopovers longer during spring migration. Woodcock captured in the Central Management Region used 2 primary migrations routes: a Western Route and a Central Route. The Western Route ran north-south, connecting the breeding and wintering grounds of the Central Management Region. The hourglass-shaped Central Route connected an area on the wintering grounds reaching from Texas to Florida, to sites throughout northeastern North America. Woodcock following the Central Route funneled between the Appalachian Mountains and the Mississippi Alluvial Valley in western Tennessee during both autumn and spring migration. A higher than anticipated percentage (36%, n = 12) of marked woodcock captured in Texas and Louisiana and monitored during spring migration migrated to breeding-period sites in the Eastern Management Region, raising questions about the biological basis of managing woodcock as separate populations. The supplementary material includes woodcock capture information (Appendix I), information on individual stopovers (Appendix II), and migration maps for individual woodcock (Appendix III).
Liming Characteristics Of A High-Calcium, Dry Flue Gas Desulfurization By-Product And Its Effects On Runoff Water Quality, Jason Richard Burgess-Conforti
Liming Characteristics Of A High-Calcium, Dry Flue Gas Desulfurization By-Product And Its Effects On Runoff Water Quality, Jason Richard Burgess-Conforti
Graduate Theses and Dissertations
In 2013, only 37% of the 32 million Mg of flue gas desulfurization (FGD) by-products generated in the United States were reused beneficially. If FGD by-products could be used as a beneficial soil amendment, millions of megagrams may be diverted away from surface impoundments and landfills. The purpose of this research was to identify the liming characteristics of a high-Ca dry FGD (DFGD) by-product in comparison to a Class-C fly ash (FA) and reagent-grade CaCO3, and to evaluate the effects of land application to a managed grassland on runoff, plant, and soil quality. Liming characteristics were determined by measuring the …
Stream Microbial Communities As Potential Indicators Of River And Landscape Disturbance In North-Central Arkansas, Wilson Howard Johnson
Stream Microbial Communities As Potential Indicators Of River And Landscape Disturbance In North-Central Arkansas, Wilson Howard Johnson
Graduate Theses and Dissertations
In the past decade, 29 shale basins have been actively developed across 20 states for extraction of natural gas (NG) via horizontal drilling/hydraulic fracturing (=fracking). This includes ~5000 wells within the Fayetteville shale of north-central Arkansas. Development often impacts both river- and landscapes, and management requires catchment-level evaluations over time, with organismal presence/absence as indicators. For this study next-generation sequencing was used to identify/characterize microbial communities within biofilm of eight Arkansas River tributaries, so as to gauge potential catchment influences. Streams spanned a gradient of landscape features and hydrological flows, with four serving as ‘potentially impacted catchment zones’ (PICZ) and …
Eucalyptus In Kenya; Impacts On Environment And Society, Brandy M. Garrett Kluthe
Eucalyptus In Kenya; Impacts On Environment And Society, Brandy M. Garrett Kluthe
Graduate Theses and Dissertations
Eucalyptus trees were introduced to Kenya a little over a century ago. European colonization along with the development of a railway system increased the demand for a fast growing wood source. The expansion of the tree across the fertile lands in Kenya raises concerns about the environmental impact on ecosystems where it has been introduced. These concerns include degraded soils, loss of water resources, co-introduction of ectomycorrhizal species, and allelopathy. Economic benefits to local landowners were also explored as well as the potential for large Eucalyptus woodlots to maximize the sequestration of CO₂ from the atmosphere. This was examined through …
Design Of A Nutrient Reclamation System For The Cultivation Of Microalgae For Biofuel Production And Other Industrial Applications, Heather Sandefur
Design Of A Nutrient Reclamation System For The Cultivation Of Microalgae For Biofuel Production And Other Industrial Applications, Heather Sandefur
Graduate Theses and Dissertations
Microalgal biomass has been identified as a promising feedstock for a number of industrial applications, including the synthesis of new pharmaceutical and biofuel products. However, there are several economic limitations associated with the scale up of existing algal production processes. Critical economic studies of algae-based industrial processes highlight the high cost of supplying essential nutrients to microalgae cultures. With microalgae cells having relatively high nitrogen contents (4 to 8%), the N fertilizer cost in industrial-scale production is significant. In addition, the disposal of the large volumes of cell residuals that are generated during product extraction stages can pose other economic …
Dissemination And Persistence Of Plasmid Located, Integron Associated Antibiotic Resistant Genes In Wastewater Treatment Plant Effluent And Stream Water Bacteria, _ Suhartono
Graduate Theses and Dissertations
Transmissible plasmid-mediated integrons play important role in the persistence and dissemination of antibiotic resistance throughout the environment. Plasmids from 139 multi-antibiotic resistant Escherichia coli recovered from wastewater treatment plant effluent and upstream and downstream receiving stream water in Northwest Arkansas were extracted and profiled. Genes of class 1 and class 2 integrase (intI), mobilization (mob), sulfamethoxazole resistance (sul), and trimethoprim resistance (dfr) were detected using PCR and confirmed through DNA sequencing. Plasmids from almost half of the isolates (47%) were transmissible with mobF12 gene as the most frequently detected mobilization gene. Plasmid-borne class 1 with and without class 2 integrons …
Evaluation Of Rusle 2 To Estimate Soil Loss From Pastures, Stasha Katrina Balkissoon
Evaluation Of Rusle 2 To Estimate Soil Loss From Pastures, Stasha Katrina Balkissoon
Graduate Theses and Dissertations
The accurate estimation of soil erosion by the Revised Universal Soil Loss Equation version 2 (RUSLE2) is critical for several conservation assessments, least of which is its use in the Phosphorus Index (PI) to identify and rank the vulnerability of agricultural fields to phosphorus (P) runoff. Earlier versions of RUSLE reported a soil loss overestimation, which were revised to give RUSLE2, where biomass production in different climatic regions was more accurately represented. RUSLE version 2.0, which contains the new vegetative biomass production routine, was evaluated using two performance indices, the Nash Sutcliffe Efficiency Index (NSE) and Index of Agreement (D) …