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Full-Text Articles in Physical Sciences and Mathematics
Environmental And Agronomic Evaluation Of Struvite In Rice Production Systems, Diego Della Lunga
Environmental And Agronomic Evaluation Of Struvite In Rice Production Systems, Diego Della Lunga
Graduate Theses and Dissertations
Furrow-irrigation constitutes an alternative water regime that has been increasingly adopted in Arkansas. Among the management of nutrients in furrow-irrigated systems, phosphorus (P) represents a substantial challenge. The environmental sustainability of rice (Oryza sativa) production systems needs to be evaluated across different water regimes and fertilizer-P sources. Therefore, the objectives of the following studies were to: i) evaluate season-long carbon dioxide (CO2) and methane (CH4) emissions and global warming potential (GWP) under different tillage treatments [i.e., conventional tillage (CT) and no-tillage (NT)] and at different site positions (i.e., up-, mid-, down-slope) along the predominant slope of a production-scale, furrow-irrigated rice …
Verification Of Astm Centrifugation Equations For Soil Suction Determination, Esteban Maclein Miranda Pinzon
Verification Of Astm Centrifugation Equations For Soil Suction Determination, Esteban Maclein Miranda Pinzon
Graduate Theses and Dissertations
The unit correction constant (B) in the ASTM D6836 standard needs to be evaluated. The B-value was proposed to be 0.00548 instead of 0.00553. This apparent discrepancy led to an investigation comparing the predicted and measured suction values for high air entry (HAE) ceramic disks. A Beckman-Coulter Model J6-MI six-bay centrifuge and a WP4C Dewpoint Potentiameter were used in the testing program. HAE ceramic disks rated with bubbling pressures of 3-bar and 5-bar were used as analogue soil specimens. The HAE ceramic disks were spun in the small-scale centrifuge to apply prescribed suction amounts and then placed in the WP4C …
Runoff Water Quality And Crop Growth As Affected By Wastewater-Derived Struvite, Machaela Morrison
Runoff Water Quality And Crop Growth As Affected By Wastewater-Derived Struvite, Machaela Morrison
Graduate Theses and Dissertations
Mined phosphate rock, used to produce phosphorus (P) fertilizers, is a finite resource. Struvite (MgNH4PO4 • 6H2O) that has been synthetically produced from a stock solution of known P and nitrogen (N) concentrations has been shown to be an effective, alternative fertilizer-P source for various crops. However, little is known about the runoff-water-quality implications from and the crop response to soil application of struvite created from an actual municipal wastewater source. This study consisted of two objectives: i) to evaluate the effects of soil [i.e., Creldon (Oxyaquic Fragiudalf), Dapue (Fluventic Hapludoll), Roxana (Typic Udifluvent), and Calloway (Aquic Fraglossudalf) series], fertilizer-P …
Effects Of Land Use On Soil Microbial Communities In Tropical Montane Forests Of Malaysian Borneo, Yang Kai Tang
Effects Of Land Use On Soil Microbial Communities In Tropical Montane Forests Of Malaysian Borneo, Yang Kai Tang
Graduate Theses and Dissertations
Land use, such as logging and forest conversion to agriculture, can modify soil physicochemical and biological properties, and affect soil health. To understand how land use change can impact soil properties and canopy structure, we used a land use gradient in Malaysian Borneo consisting of six sites, including old growth forests, mixed forests, and agriculture fields. Specifically, we aimed to answer the following questions: (1) How do soil physicochemical properties vary across land use types? (2) Does bacterial diversity and composition vary across different land use types? (3) Does fungal diversity and composition vary across different land use types? We …