This study focuses on Long Pond, a groundwater-fed sinkhole lake in Georgia, which does not exhibit any evidence of eutrophication drivers despite high concentrations of sedimentary phosphorus (P) (> 3000 mg/kg P) in the recent sediment record. Chemical analyses have shown a strong correlation (r2>0.99) between P and aluminum (Al) throughout the core, suggesting Al plays a significant role in sequestering most of the P, and limiting its availability to phytoplankton, thereby inhibiting eutrophication. The purpose of this study is to decipher P and Al physicochemical associations in the sediments. After the samples were fractionated into amorphous and non-amorphous phases, the correlation was maintained in both phases. Evidence suggests two modes of Al-P associations: a sorption and/or co-precipitation occurring mostly in the amorphous phase and a mode whereby Al and P are being inputted to the lake bound together.

Phosphorous (P) is an essential nutrient, playing a central role in the life of a bacterial cell. It is involved in cellular metabolic pathways, cell signaling and is a component of many of the cell’s macromolecules. Since a majority of the biosphere’s microorganisms have not yet been cultured, much more can be learned about the biochemical and genetic mechanisms that govern bacterial P metabolism. The function-driven approach to metagenomics was applied to study P metabolism in the bacterial communities present in pulp and municipal wastewater treatment plant activated sludge and soil, leading to the isolation and identification of three new phosphatases, genes involved in P transport, regulation of P related functions and additional genes which may be important for the bacterial cell’s adaptation to the above communities. The identification of two new nonspecific acid phosphatases (NSAPs) phoNACX6.13 and phoNBCX4.10 and an alkaline phosphatase, phoAACX6.71, belonging to the nucleotide pyrophosphatase phosphodiesterase (NPP) family is reported here. The genes for the three phosphatases were cloned, sequenced, and analysed for upstream regulatory sequences in addition to biochemical characterization of their protein products. PhoB-binding sites were found upstream to phoAACX6.71 and NSAP phoNACX6.13, suggesting these genes are governed by the mechanisms of the previously described “pho” regulon. The two NSAPs have pH optima in the acidic neutral range while the alkaline phosphatase has an optimal pH at 9.5. The three phosphatases appear to be distantly related to known bacterial phosphatase enzymes. Phylogenetic analysis shows the newly identified NSAPs appear on a separate clade from known bacterial NSAPs. Key amino acid residues involved in the catalytic site of these NSAPs were identified in PhoNACX6.13 and PhoNBCX4.10.In PhoAACX6.71, key amino acid residues involved in catalysis and metal cofactor coordination were identified. The roles of these residues were confirmed based on the predicted molecular structure of these proteins. The structures indicate the three proteins are globular with folding patterns suitable for catalytic residues to bind and cleave the P substrate. This is the first report of functional characterization of phosphatases from uncultured bacteria. In addition to exploring the hydrolysis of phosphate esters, the transport and metabolism of other P compounds was also investigated. By phenotypic complementation of phosphonate growth deficient mutants of the legume symbiont, Sinorhizobium meliloti and large scale sequencing of selected metagenomic clones, 92 ORFs were isolated. As expected, about 25% of these ORFs are P transport proteins and P related regulators. Genes involved in other regulatory functions made up about 12% of the total while genes related to Nitrogen metabolism and assimilation account for about 8% of the newly identified ORFs. About 30% of the ORFs encoded general cellular functions or hypothetical proteins of unknown function. The results of this investigation demonstrate the effectiveness of functional metagenomics in studying genetic diversity of bacteria inhabiting complex microbial communities and in identifying new proteins of interest.

Eutrophication of lakes and streams are nowadays a well known environmental problem and implies an enrichment of the nutrients phosphorus (P) and nitrogen (N). Phosphorus is considered to be the most important component for the growth of aquatic plants and leads in too large quantities to an intensification of growth. Phosphate (PO4) is the fraction of phosphorus that can easiest be taken up by plants and thus have the greatest impact on eutrophication. Increased plant growth in lakes and unfavorable conditions for aquatic animals are two examples of negative consequences. A significant portion of the increased nutrient supply to nearby water can be derived to phosphate leaching from agricultural areas, where private sewers and agriculture is two main sources. How much of the diffuse leakage of phosphate derived from each source is uncertain. With an improved understanding of how the source and flow distribution of phosphate relationship works in an agricultural dominated catchment could a more cost efficient planning for choice of methods against leakage of the nutrient be achieved. The source and flow distribution of phosphate was therefore studied and a high resolution set of SMHI's hydrological model HYPE where set up over the area. Sampling of phosphate from different parts of the area where used together with modeled water flow and phosphate transport where calculated. Upstream and downstream dynamics of phosphate were compared during high water flow. Also sampling of the oxygen isotopic composition in phosphate ions from sewage and agricultural land were analyzed and used to estimate the source distribution at different situations of water flow. The collected information from these studies where used to identify from which source to phosphate and during which flow the leakage of phosphate where the most in the area. In addition to this an evaluation of the importance of the time and space resolution for the HYPE-model where made. Phosphate transports in space shows that the sewage-dominated basins where the areas that leak most phosphate per area unit and during low water flows. Agricultural areas account for more significant leakage during a high water flow. This is evident in autumn and winter and less evident during spring and summer. Oxygen isotopic composition of phosphate ions from wastewater and agricultural land could with a 99 % confidence be separated. This information was used for source separation of phosphate sources where sewage was the main source of water flow up to 23 l/s. At higher water flow increases agricultural land as a primary source and increases positively linearly with increasing water discharge. Both studies indicate that sewage accounts for the greatest leakage during low water. During a snow-melting period the phosphate leaching is highest at the beginning and gradually flushed out from the soil when the water flow remains high for several days in a row. The importance of a high resolution time and space step affected modeled data marginally positive in HYPE where time step had a more important role.

Phosphorous (P) is an essential nutrient, playing a central role in the life of a bacterial cell. It is involved in cellular metabolic pathways, cell signaling and is a component of many of the cell’s macromolecules. Since a majority of the biosphere’s microorganisms have not yet been cultured, much more can be learned about the biochemical and genetic mechanisms that govern bacterial P metabolism. The function-driven approach to metagenomics was applied to study P metabolism in the bacterial communities present in pulp and municipal wastewater treatment plant activated sludge and soil, leading to the isolation and identification of three new phosphatases, genes involved in P transport, regulation of P related functions and additional genes which may be important for the bacterial cell’s adaptation to the above communities. The identification of two new nonspecific acid phosphatases (NSAPs) phoNACX6.13 and phoNBCX4.10 and an alkaline phosphatase, phoAACX6.71, belonging to the nucleotide pyrophosphatase phosphodiesterase (NPP) family is reported here. The genes for the three phosphatases were cloned, sequenced, and analysed for upstream regulatory sequences in addition to biochemical characterization of their protein products. PhoB-binding sites were found upstream to phoAACX6.71 and NSAP phoNACX6.13, suggesting these genes are governed by the mechanisms of the previously described “pho” regulon. The two NSAPs have pH optima in the acidic neutral range while the alkaline phosphatase has an optimal pH at 9.5. The three phosphatases appear to be distantly related to known bacterial phosphatase enzymes. Phylogenetic analysis shows the newly identified NSAPs appear on a separate clade from known bacterial NSAPs. Key amino acid residues involved in the catalytic site of these NSAPs were identified in PhoNACX6.13 and PhoNBCX4.10.In PhoAACX6.71, key amino acid residues involved in catalysis and metal cofactor coordination were identified. The roles of these residues were confirmed based on the predicted molecular structure of these proteins. The structures indicate the three proteins are globular with folding patterns suitable for catalytic residues to bind and cleave the P substrate. This is the first report of functional characterization of phosphatases from uncultured bacteria. In addition to exploring the hydrolysis of phosphate esters, the transport and metabolism of other P compounds was also investigated. By phenotypic complementation of phosphonate growth deficient mutants of the legume symbiont, Sinorhizobium meliloti and large scale sequencing of selected metagenomic clones, 92 ORFs were isolated. As expected, about 25% of these ORFs are P transport proteins and P related regulators. Genes involved in other regulatory functions made up about 12% of the total while genes related to Nitrogen metabolism and assimilation account for about 8% of the newly identified ORFs. About 30% of the ORFs encoded general cellular functions or hypothetical proteins of unknown function. The results of this investigation demonstrate the effectiveness of functional metagenomics in studying genetic diversity of bacteria inhabiting complex microbial communities and in identifying new proteins of interest.

Nutrients in the sediments of Lake Manitoba’s south basin are resuspended regularly due to its shallow, polymictic nature. In 2009 short sediment core samples were used to determine an internal available nutrient load from sediment of 17,533 tonnes total nitrogen (TN) and 167 tonnes total phosphorous (TP). Water samples were collected at the Whitemud River and Assiniboine River Diversion (ARD) to determine the N and P input to the lake, resulting in an estimate of a total point source input of 3,547 tonnes of TN and 1,130 tonnes of TP. Open water samples were collected to determine a suspended content of 9.2 tonnes of TN /km2 or and 1.7 tonnes of TP/km2. The ARD is the largest contributor of TP to the south basin. The internal sediment pool is a significant source of TN, and when the ARD does not operate, the largest input of TP to the south basin.

Nutrients in the sediments of Lake Manitoba’s south basin are resuspended regularly due to its shallow, polymictic nature. In 2009 short sediment core samples were used to determine an internal available nutrient load from sediment of 17,533 tonnes total nitrogen (TN) and 167 tonnes total phosphorous (TP). Water samples were collected at the Whitemud River and Assiniboine River Diversion (ARD) to determine the N and P input to the lake, resulting in an estimate of a total point source input of 3,547 tonnes of TN and 1,130 tonnes of TP. Open water samples were collected to determine a suspended content of 9.2 tonnes of TN /km2 or and 1.7 tonnes of TP/km2. The ARD is the largest contributor of TP to the south basin. The internal sediment pool is a significant source of TN, and when the ARD does not operate, the largest input of TP to the south basin.

In the past twenty years the grain industry has experienced production declines in Virginia due to inability to compete with Midwestern grain producers. During this same time, consumption of grain by the poultry industry in Virginia has expanded rapidly. The levels of production and consumption of grain in Virginia are calculated and described on a state, regional, and county basis. Handling, storage, and marketing practices of grain in Virginia are assessed and described. Several different alternatives are presented and evaluated to determine their ability to improve the competitive position of Virginia corn with Midwestern states through the use of poultry litter to decrease production costs and present opportunities for producers to achieve better prices. / Master of Science

No description available.

Virginia's Coastal Plain region contains the majority of the state's agricultural production despite having low nutrient soils. The soils in this region are predominantly coarse-textured acid soils with low cation exchange capacities (CEC) (< 3 cmol kg-1) and thus frequently exhibit nutrient deficiencies, including cationic nutrients which are not easily lost by leaching in soils with greater CEC. As a result, soils require careful nutrient management to maintain production levels. Soybean (Glycine max), the world's fourth largest crop, shows sensitivity to manganese availability and regularly experiences deficiency symptoms in low-CEC coastal plain soils. Tomato (Solanum lycopersicum) production, one of the 3 largest vegetable production systems in the world, requires careful management of various nutrients, particularly phosphorous, sulfur, and boron, for proper fruit development. Two novel coated fertilizer products consisting of granular KCl coated in a nutrient powder and a sugar-acid chelating agent are investigated as multi-nutrient sources for soybeans and tomatoes. A comprehensive review of the chemistry, behavior, and functionality of key nutrients provided by the fertilizer (P, S, Mn, and B) in both soils and plant tissues and the current state of chelate use in agriculture is provided along with related production issues with tomatoes and soybean. A greenhouse study investigating the ability of the first coated product (Mn + B coated KCl) to provide micronutrients to soybeans was conducted. Using both low and high organic matter (OM) soils (10 g kg-1; 36 g kg-1), Mn + B coated KCl increased soil Mn compared to no fertilizer and uncoated KCl. Additionally, Mn + B coated KCl increased total above ground tissue Mn compared to control and uncoated KCl for the low OM soil but not for the high OM soil, which was likely due to OM leading to the formation of metal-ligand complexes. There were no significant results regarding B concentration in either the soil or plant tissue due to the low application rate provided by the coating. The same fertilizer (Mn + B coated KCl) was investigated under field conditions to determine if increased soil and tissue Mn can be maintained under various environmental factors. Our results found that for all growing seasons and locations, there were no significant treatment differences between months for both Mn and B, but total monthly averages did fluctuate between months, probably reflecting changes in soil moisture and redox status. When averaged across the entire growing season, differences between treatments were inconsistent. Under field conditions, environmental conditions such as soil moisture and leaching likely masked any consistent treatment effects of the coated products. Two potential soil amendments, P + S + B coated KCl and glucoheptonate (GH), were investigated for their ability to provide nutrients to tomatoes. Three greenhouse trials, each lasting 3 weeks, were conducted. In the first trial, P + S + B coated KCl was compared to the current agronomic recommendation rates for P, S, and B. The coated KCl significantly increased soil and plant tissue P and B compared to all but the KCl + P and KCl + B treatments. The second trial was a glucoheptonate rate trial and showed a significant positive correlation between GH rate and soil and tissue B. The third trial combined and compared the coated KCl and GH products and showed that the treatments containing the coated KCl had significantly increased P, S, and B soil and tissue concentrations, with GH application having no synergistic effect / Ph. D. / The majority of the Virginia’s agricultural production occurs on the nutrient poor soils of the coastal plains where nutrient deficiencies are common. As a result, careful nutrient management strategies are required to maintain crop production levels, including major crops like soybean and tomato. Soybean (Glycine max) show sensitivity to manganese (Mn) availability and regularly experience deficiency symptoms in this region. On the other hand, tomato (Solanum lycopersicum) production requires careful management of nutrients such as phosphorous, sulfur, and boron for proper fruit development. In this dissertation, two novel coated fertilizer products, granular KCl coated in a nutrient powder and a sugar-acid chelating agent, are investigated as multi-nutrient sources for soybeans and tomatoes. This dissertation starts with a comprehensive review of the chemistry, behavior, and functionality of key nutrients provided by the fertilizer in soils and plant tissues, followed by a review of the current state of sugar acid use in agriculture. The production systems for soybeans and tomatoes for VA and the USA will also be discussed. The second component of this dissertation is a greenhouse study investigating the ability of the first coated product (Mn+B coated KCl) to provide micronutrients to soybeans. The Mn+B coated KCl significantly increased Mn compared to control and uncoated KCl treatments in the soil for both soil types and in tissue for the low OM soil. The third component of this dissertation investigates the same fertilizer under field conditions. Our results showed that for all growing seasons and locations, there were no significant treatment differences between months for both Mn and B, but monthly averaged concentrations did fluctuate over time, probably reflecting seasonal environmental shifts. When averaged annually, inconsistent differences were seen between treatments. Under field conditions, environmental conditions like increased soil moisture and leaching likely masked any consistent treatment effects of the coated products. The fourth component of this dissertation investigates two potential soil amendments, the second coated KCl product (P+S+B coated KCl) and glucoheptonate (GH), for their ability to provide nutrients to tomatoes. The study consists of 3 separate greenhouse trials, each lasting 3 weeks. In the first trial, P+S+B coated KCl was compared to the current agronomic recommendation rates for P, S, and B. The coated KCl significantly increased soil and plant tissue P and B compared to all but the KCl + P and KCl + B treatments. The second trial was a glucoheptonate rate trial and showed a significant positive correlation between GH rate and soil and tissue B. The third trial combined and compared the coated KCl and GH products and showed that the treatments containing the coated KCl had significantly increased P, S, and B soil and tissue concentrations, with GH application having no enhancing effect.

In the state of Virginia, population growth and the associated increases in municipal wastewater, along with the threat of EPA regulations, will increase the need for reductions in phosphorous (P) loads in surface waters in order to meet and maintain water quality standards for the Chesapeake Bay. Agriculture contributes 49% of P entering the Bay; therefore, it can be expected that agriculture will be targeted as a source of P reductions. Spatially variable physical and socioeconomic characteristics of a watershed and its occupant farms affect both the decisions made by farmers and the transport of nutrients. Evidence suggests that spatially variable characteristics should be considered when designing policies to control nonpoint sources of water pollution. However, spatial information can be expensive to collect and the evidence is not conclusive as to the level of information required to analyze specific pollution-control policies. The objective of this study was to estimate the accuracy of predicted compliance costs and changes in P deliveries resulting from mandatory buffer installation and mandatory nutrient management for three alternative levels of information, relative to the population of farms in a Virginia watershed. For each information case, an economic model, FARMPLAN, was used to determine the profit maximizing levels of inputs, outputs and gross margins. Selected crop rotations and P applications were used as inputs to the physical model, PDM, which estimated the levels of P delivered to the watershed outlet. The compliance cost and P reduction estimates for the three alternative cases were compared to those of the population to determine their accuracy. The inclusion of greater levels of spatial information will lead to more accurate estimates of compliance costs and pollution reductions. Estimates of livestock capacity are more important to making accurate predictions than are farm boundaries. Differences in estimates made using different levels of information will be greater when the farmers have greater flexibility in meeting the policy requirements. The implications are that additional spatial information does not aid in the selection of one policy over the other, but can be useful in when estimating costs for budgeting purposes, or when evaluating how farmers will respond to the policy. / Master of Science