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The San Joaquin Valley is regarded as one of the most productive agricultural regions in the world. This extensive agriculture has, however, caused extensive pollution of both ground water and surface water. This thesis develops a hydrologic model of the surface and ground waters of the San Joaquin Valley. Such modeling is useful in the development and implementation of water quality regulations such as Total Maximum Daily Loads (TMDLs). A properly validated watershed simulation model can supplement data collection and can account for watershed characteristics including topography, soils, climate, land cover, anthropogenic activities, as well as simulate watershed responses including streamflow and contaminant concentration at detailed spatial and temporal scales. Models can be used as a decision support tool to manage complex agricultural watersheds such as the San Joaquin Valley. Once developed, such watershed simulation models can be used to identify contaminant source areas, locate hot-spot areas that have high pollution risk, identify optimal monitoring sites, and determine best management practices to cost-effectively reduce pollution. As a step towards developing a model as a decision making tool, the objective of this study is to appraise effectiveness of a widely used watershed simulation model known as Soil and Water Assessment Tool (SWAT) to simulate hydrology of the San Joaquin Valley watershed. For this thesis SWAT was successfully calibrated for streamflow at several locations in the watershed, thus demonstrating the capability of the model to represent the complex, snow-driven hydrology of the San Joaquin Valley watershed including dams and reservoirs located in the mountains, and agricultural activities and flow diversion systems in the valleys. Calibration of sediment and nitrate loadings in the surface waters were also attempted; the results were, however, less than convincing compared to stream flow calibration. Future studies are recommended to improve accuracy of the water quality predictions and to evaluate long-term effectiveness of various watershed management policies in improving surface water and groundwater quality in the San Joaquin Valley. The hydrology model developed in this study can be used as a foundation for future studies that focus on water quality.

Teff (Erogrostis tef (Zucc.)), an annual warm-season grass from Ethiopia, has potential to provide forage during periods when cool-season grass growth is limited by high temperatures. An experiment was conducted at three Virginia locations in 2009 and 2010 to determine the effect of nitrogen (N) fertilization rate and source on the yield, nutritive value, and nitrate content of teff. Nitrogen (N) was applied at 0, 45, 90, and 135 kg plant available N ha-1 as a single application of either ammonium nitrate (AN) or broiler litter (BL) at seeding. The experimental design was a randomized complete block with a two-factor factorial treatment design (N rate and source) and four replications. Biomass yield typically peaked at the 90 kg N ha-1 rate, but rarely showed an increase beyond the 45 kg N ha-1 rate. Yield ranged from 2325 to 7542, 1477 to 6151, and 1805 to 8875 kg DM ha-1 for the Blacksburg, Southern Piedmont, and Shenandoah Valley locations, respectively. Crude protein and total digestible nutrients ranged from 70 to 240 g kg-1 and 460 to 700 g kg-1, respectively. Nitrate concentrations increased with increase in N fertilization but source had no effect on nitrate concentration. Typically, nitrates only posed a health risk for ruminant livestock at N rates above 90 kg N ha-1, but dangerous levels were present occasionally at the 0 and 45 kg N ha-1 rates. The results from this study indicate that teff responds to moderate rates of N and could provide summer forage for grazing livestock in the mid-Atlantic region. / Master of Science in Life Sciences

The purpose of the investigation was to determine the interfering effect on the polarographic method of nitrate analysis of certain chemicals commonly employed in the water purification process. Chemicals tested consisted of coagulants, a disinfectant, and an algaecide. A. “synthetic” water of known chemical consistency was used for diluting purposes. The investigation consisted of two phases; (1) establishing a standard curve with 95 per cent confidence limits of nitrate concentration versus current reading, and ( 2) determining the amount of nitrate recovery in samples containing known nitrate concentrations and certain chemical additives. A further investigation was made of the effect of chemicals revealing a pronounced interference during the initial test. The results obtained indicated that ferric chloride, ferric sulfate, chlorine, and copper sulfate did not interfere with the nitrate analysis. Alum and ferrous sulfate caused a significant interference. The loss in nitrate recovery due to the presence of alum in solution was found to be directly proportional to the alum concentration. Nitrate recovery was reduced from 0 to 10% by alum dosages of 0 to 10 gpg respectively. Although ferrous sulfate caused considerable reduction in nitrate recovery, this is readily explained since ferrous sulfate may be used for the destruction of nitrate in polarographic procedure. When a number of samples were analyzed, the average time required was about 20 minutes per sample. Thus, the time required to perform a nitrate analysis by the polarographic method compares favorably with other methods of analysis. / Master of Science

Nutrient loss has been a problem in the agricultural field for as long as fertilizers have been used. Not only is it cost inefficient, it can be an environmental hazard when these nutrients enter the watershed. Biochar, both untreated and treated, have been shown to improve soil’s ability to retain nutrients and increase residency time. However, the sorption capacity of biochar when amended with different soil types, has not been explored sufficiently. Batch reactors and sediment columns were used to determine the efficiency of magnesium oxide treated biochar in three different soil types to retain nitrates and phosphates. The results showed that while largely ineffective for nitrate amendment, this approach could be very effective for the amendment of phosphates in all three soil types. Kinetic studies showed that effectiveness was immediate with phosphates. Absorption occurred more slowly with nitrates, and after a time effectiveness was reversed.

No description available.

L'eau est vitale pour l'existence de tous les organismes vivants, mais cette ressource précieuse est de plus en en plus menacée et polluée à cause de l’augmentation de la demande en eau potable qui résulte à la fois de l’accroissement de la population mondiale mais aussi de l’activité économique tant au niveau de l’agriculture que de l’industrie. La préservation de cette ressource est aujourd'hui l'une des premières préoccupations de la recherche dans le domaine du traitement des eaux. Dans ce travail, l’élimination de deux polluants typiques des activités humaines, les nitrates et la carbamazépine, est étudiée au moyen de méthodes de traitements électrochimiques et biologiques non-conventionnelles. Le travail se concentre d'une part sur l'électrocoagulation (EC) qui associe les avantages d'être non-spécifique et de combiner plusieurs mécanismes de dépollution simultanés (adsorption, électro-oxydation ...); d’autre part, un traitement biologique innovant de faible coût utilisant une algue verte, Ankistrodesmus braunii, a été développé. Enfin, les avantages, limitations et perspectives de ces deux procédés sont comparés à ce qui existe dans la littérature et sont discutés. / Water is vital to the existence of all living organisms, but this valued resource is increasingly being threatened and polluted as human populations and activities grow and demand more water of high quality for domestic purposes and economic activities. Wastewater treatment for resource preservation is nowadays one of the first concerns of research in this field of science. In this work, two typical pollutants from agriculture and domestic activity, Nitrates and Carbamazepine, are quantitatively addressed by non-conventional electrochemical and biological treatment methods. The study focuses, on the one side, on electrocoagulation (EC) that exhibits the advantages to be non-specific and to combine various depollution mechanisms (adsorption, electro-oxidation...) that act simultaneously; on the other side, innovative and low-cost biological treatments using green algae, Ankistrodesmus braunii, are developed. Finally, the respective advantages, limitations and perspectives of these processes are compared to the literature and discussed.

Master of Science / Department of Horticulture, Forestry, and Recreation Resources / Charles J. Barden / Contaminated water poses a major environmental and human health problem, which may be resolved by using the emerging phytoremediation technology. This plant-based cost-effective approach to remediation takes advantage of the ability of plants to concentrate elements and compounds from the environment, to absorb and transpire large amounts of water, and to metabolize various molecules in their tissues. The city of Manhattan’s Biosolids Farm located near Manhattan, Kansas is using the emerging technology of phytoremediation. The Biosolids Farm remediation began in the mid 1990’s; with a large planting of alfalfa with the goal of absorbing excess nitrates from soil and ground water. In 2004, hundreds of trees were planted, to serve as a protective buffer between the biosolids disposal area and the Kansas River. In 2006, a trench study was installed to improve tree establishment on a sandy outwash area close to the Kansas River using Siberian elm seedlings and rooted cottonwood cuttings from Nebraska and true cottonwood seedlings from Missouri. Treatments included trenching, dairy cattle composted manure, and tree shelters. This planting was done to serve as a vegetative barrier and to aid in reducing nitrate movement into the Kansas River. There were interaction between the tree sources and the trenching, compost and shelter treatments. The treatments showed significant interactions with tree sources with the addition of compost and shelters with a p value of 0.0438, and trenching and compost p-value 0.0021. Tree survival was significantly improved with the use of tree shelters.

Call number: LD2668 .T4 1964 M43 / Master of Science