Infection of tall fescue (<i>Festuca arundinacea</> Schreb.) with the endophyte fungus (<i>Acremonium coenophialum</i>, Morgan-Jones and Gam) has been associated with toxicity symptoms observed in cattle. The overall objective was to investigate the influence of endophyte infection on growth and chemical composition of tall fescue and the toxicity of endophyte-infected (EI) tall fescue to cattle. In a greenhouse study with pairs of genetically identical EI and non-infected (NI) ‘Kenhy’ tall fescue clones, concentration of N, Ca, Mg, Al, B, Mn and Zn was higher and K and S was lower in NI, compared to EI tall fescue. Insect resistance was higher in EI, compared to NI. Yield and chemical composition of high and low EI tall fescue were measured at four growth stages (stockpiled, prebloom, bloom and regrowth after harvest at bloom), two sites (Glade Spring and Blackstone) and three rates of N fertilization (0, 40 and 80 kg/ha) in a field study. Tall fescue grown at Glade Spring was higher in N, Mg, Al, Cu, Fe and Mn, compared to Blackstone. Nitrogen fertilization increased N, Mg, Ca, B, Cu, Na, Zn and decreased NDF, ADF, cellulose, P and S concentration in tall fescue. Neutral detergent fiber, ADF, cellulose, lignin, Fe and Na were higher in low, compared to high EI tall fescue. Concentrations of Cu, Na and Zn in stockpiled and Ca, Cu, Na and Zn in bloom-cut tall fescue hay were below dietary requirements for 227-kg steers. A disc meter was also evaluated for use in predicting yield of tall fescue. The meter is useful for non-destructive estimation of yield. Three feeding studies were conducted with steers (6/treatment/year). Diets were orchardgrass/alfalfa hay, spring-cut EI tall fescue hay, spring-cut EI tall fescue silage and fall-cut EI tall fescue silage. Serum prolactin and cholesterol were depressed in steers fed fescue hay and silages, compared to steers fed orchardgrass/alfalfa hay. Differences in mineral composition of hay and silage were reflected in serum minerals in steers. Ergopeptine alkaloids in EI tall fescue may have contributed to the depression of serum prolactin. The spring-cut silage contained the highest concentration of ergopeptine alkaloids, compared to other diets. Steers fed the spring-cut tall fescue silage had the lowest basal and thyrotropin-releasing hormone stimulated prolactin compared to steers fed the other diets. / Ph. D.

The production of beef cattle on pasture in Virginia has long been an important industry. The leading cattle producing sections in the state are Southwest Virginia, the Shenandoah Valley, and northern Virginia. In Southwest Virginia, due to the abundant growth of excellent quality bluegrass, most of the butcher cattle are grass-fattened and sold in the fall at two to three years of age. In the Shenandoah Valley and northern Virginia the common practice is to follow the feed lot and grain supplement methods of production. The movement to market is less seasonal than in Southwest Virginia. Virginia cattle that are not used for local consumption now find their chief outlets north of the Potomac River. The principal markets to which they are shipped are Lancaster, Jersey City, Baltimore, and Philadelphia. A limited number are sent to Richmond. Cattle going to Lancaster are comparatively light in weight and are purchased mostly for further feeding in Pennsylvania and Maryland feed lots. Those going to Jersey City, Baltimore and Philadelphia are usually bought for immediate slaughter. Cattle shipments to these markets from Virginia are shipped during a comparatively short period each year. There were only 71.84 per cent as many cattle shipped from the area in Virginia served by the Norfolk and Western Railroad in 1931 as in 1930. This decline was probably due to economic conditions and to the shortage of grass and feed following the dry seasons in 1930 and 1931. The local and incoming Virginia cattle shipments are few compared to outgoing shipments. Most of the local shipments in Virginia are from the extreme southwestern counties to the grass-fattening areas in the same section of the state. These shipments occur chiefly in the fall and spring. Cattle shipments received into this state over the Norfolk and Western Railroad come from Tennessee, Texas and North Carolina, and go to southwestern Virginia counties for stocker and feeder purposes. Sheep production in Virginia has been increasing since 1921. Sheep raising offers many advantages due to their ability to utilize profitably many products that would be of little value for other feeding purposes. A double cash return is secured from the wool and lamps. Southwest Virginia is the chief lamp producing section. The principal markets to which Virginia lamps are shipped are Jersey City and Baltimore. These lambs are usually bought for immediate slaughter. The marketing of Virginia lambs is highly seasonal. Most of them are marketed between May 15 and July 30. Shipments of sheep and lamps locally and into Virginia is of little significance since the demand for feeders is not great, due to the method of production of spring lambs followed in this state. Hog production in Virginia is confined mostly to certain areas. The leading producing sections are the Shenandoah Valley, northern Virginia, and eastern Virginia. Hogging down the peanut crop is the method of production most common in eastern Virginia. The eastern part of the state is the leading hog producing section. The bulk of the hogs marketed from Virginia go to the markets at Baltimore or Richmond. Incoming hog shipments into Virginia over the Norfolk and Western Railroad are of little importance compared to outgoing shipments. Most of them go to the eastern part of Virginia. Livestock production in Virginia during 1927, 1928 and 1929 was increasing. Prices were also advancing during this period. / M.S.

by Ng Sai Leung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1990. / Bibliography: leaves [172]-[182] / ABSTRACT --- p.iii / ACKNOWLEDGEMENTS --- p.V / TABLE OF CONTENT --- p.vii / LIST OF FIGURES --- p.xii / LIST OF TABLES --- p.xiv / LIST OF PLATES --- p.xvii / LIST OF APPENDICES --- p.xviii / CHAPTER --- p.Page / Chapter I --- INTRODUCTION --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Objectives --- p.3 / Chapter 1.3 --- Significance --- p.3 / Chapter 1.4 --- Literature review --- p.5 / Chapter 1.5 --- Scope and approach of the study --- p.8 / Chapter II --- METHODOLOGY --- p.11 / Chapter 2.1 --- Conceptualization --- p.11 / Chapter 2.2 --- Soil characteristics / Chapter 2.2.1 --- Site selection --- p.12 / Chapter 2.2.2 --- Descriptions of soils for investigation --- p.15 / Chapter 2.3 --- Preliminary percolation test and soil preparation --- p.24 / Chapter 2.4 --- Column design --- p.25 / Chapter 2.5 --- Routine operation --- p.28 / Chapter 2.6 --- Sampling procedure --- p.29 / Chapter 2.7 --- Time schedule of the experiment --- p.30 / Chapter III --- ANALYTICAL METHODS --- p.31 / Chapter 3.1 --- Soil characteristics --- p.31 / Chapter 3.2 --- Soil leachate --- p.37 / Chapter 3.3 --- Continuous monitoring of the column system --- p.42 / Chapter 3.4 --- Manipulation and analysis of data --- p.43 / Chapter 3.5 --- Remarks --- p.44 / Chapter IV --- INITIAL STATE OF THE SYSTEM --- p.45 / Chapter 4.1 --- Slurry characteristics --- p.45 / Chapter 4.2 --- Soil matrix --- p.47 / Chapter 4.3 --- Blank soil leachate --- p.50 / Chapter 4.5 --- Summary --- p.51 / Chapter V --- HYDRAULIC PERFORMANCE OF THE COLUMNS --- p.53 / Chapter 5.1 --- Hydraulic considerations of disposal design --- p.53 / Chapter 5.1.1 --- Soil clogging phenomenon --- p.54 / Chapter 5.1.2 --- Significance of soil clogging --- p.55 / Chapter 5.2 --- Morphology of clogging layer --- p.55 / Chapter 5.3 --- Infiltration regimes of the columns --- p.59 / Chapter 5.3.1 --- Kostiakov infiltration model --- p.59 / Chapter 5.3.2 --- Factors affecting infiltration regimes --- p.63 / Chapter 5.4 --- Practical recommendations --- p.65 / Chapter 5.4.1 --- Recommended dosage rate --- p.65 / Chapter 5.4.2 --- Time of failure --- p.66 / Chapter 5.4.3 --- Recovery of the system --- p.67 / Chapter 5.5 --- Summary --- p.68 / Chapter VI --- PURIFICATION EFFICIENCY OF THE SYSTEM --- p.70 / Chapter 6.1 --- PH --- p.70 / Chapter 6.2 --- Specific conductivity --- p.71 / Chapter 6.2.1 --- Ion movement pattern --- p.74 / Chapter 6.2.2 --- Ion movement mechanism --- p.77 / Chapter 6.3 --- E. coli --- p.78 / Chapter 6.3.1 --- E. coli removal pattern --- p.81 / Chapter 6.3.2 --- E. coli overview --- p.82 / Chapter 6.4 --- Carbon --- p.83 / Chapter 6.4.1 --- Carbon attenuation pattern --- p.84 / Chapter 6.4.2 --- Carbon transformation mechanisms --- p.93 / Chapter 6.5 --- Nitrogen --- p.95 / Chapter 6.5.1 --- Nitrogen attenuation --- p.96 / Chapter 6.5.2 --- Nitrogen transformation mechanisms --- p.103 / Chapter 6.6 --- Phosphorus --- p.106 / Chapter 6.7 --- Summary --- p.112 / Chapter VII --- CHEMICAL QUALITY OF SOIL LEACHATE --- p.113 / Chapter 7.1 --- Cluster analysis of leachate samples --- p.114 / Chapter 7.1.1 --- Clustering of soil leachate --- p.115 / Chapter 7.1.2 --- Implications --- p.118 / Chapter 7.2 --- Discriminant analysis of leachate samples --- p.119 / Chapter 7.2.1 --- Discriminant functions --- p.119 / Chapter 7.2.2 --- Scanning the misclassified samples --- p.123 / Chapter 7.3 --- Spatial and temporal changes of soil leachate --- p.124 / Chapter 7.5 --- Summary --- p.127 / Chapter VIII --- CONTROLLING FACTORS OF THE LEACHATE QUALITY --- p.128 / Chapter 8.1 --- Interrelationship of leachate chemical quality --- p.130 / Chapter 8.2 --- Analytical framework --- p.133 / Chapter 8.3 --- Evaluating the effect of system characteristics --- p.135 / Chapter 8.3.1 --- "Effects on ""degradation""" --- p.137 / Chapter 8.3.2 --- "Effects on ""soil retention""" --- p.138 / Chapter 8.3.3 --- "Effects on ""nitrification""" --- p.138 / Chapter 8.3.4 --- Overall effect --- p.139 / Chapter 8.4 --- Pattern of pollutant attenuation --- p.140 / Chapter 8.5 --- Relative performance of five soils and the effect of depth --- p.142 / Chapter 8.5.1 --- Relative purification efficiency of each soil --- p.143 / Chapter 8.5.2 --- The effect of soil depth on purification --- p.144 / Chapter 8.6 --- Evaluating the effect of slurry concentration --- p.146 / Chapter 8.7 --- Evaluating the effect of management practices --- p.148 / Chapter 8.7.1 --- Gravel washing --- p.148 / Chapter 8.7.2 --- Raking --- p.150 / Chapter 8.8 --- Summary --- p.151 / Chapter IX --- CHANGES OF SOIL CHEMICAL PROPERTIES --- p.153 / Chapter 9.1 --- Soil reaction pH --- p.153 / Chapter 9.2 --- Soil electrical conductivity (SEC) --- p.156 / Chapter 9.3 --- Soil total organic carbon (TOC) --- p.158 / Chapter 9.4 --- Soil total nitrogen (TN) --- p.158 / Chapter 9.5 --- Soil total phosphorus (TP) --- p.162 / Chapter 9.6 --- Summary --- p.162 / Chapter X --- CONCLUSION --- p.165 / Chapter 10.1 --- General review of the performance of the columns --- p.165 / Chapter 10.2 --- Purification pathways and contaminant attenuation --- p.166 / Chapter 10.3 --- Factors affecting the purification --- p.167 / Chapter 10.4 --- Impacts of slurry application on the soil properties --- p.168 / Chapter 10.5 --- Practicability of soakaway and recommendations --- p.168 / Chapter 10.6 --- Suggestion and discussion --- p.169 / Chapter 10.6.1 --- Experimental design --- p.169 / Chapter 10.6.2 --- Operational improvement --- p.170 / Chapter 10.6.3 --- Statistical considerations --- p.171 / BIBLIOGRAPHY / APPENDICES

Thesis (M.Sc. (Pasture Science)) --University of Limpopo, 2014 / Due to shortage of adequate pasture in large parts of South Africa, winter survival poses a problem to farmers. A shortage in winter grazing is the major problem on most farms in South Africa. Animals loose weight in winter which leads to low reproduction, production of milk, mutton and meat. The winter feed shortages counteract also the possible good performance of animals during summer. Winter supplementation contributes largely to high input costs in livestock production, which can make this enterprise uneconomically. This study was done at two different localities: Hygrotech’s experimental farm at Dewageningsdrift, Gauteng and Nooitgedacht Agricultural Development center, Mpumalunga. Five winter fodder crop cultivars (Witteberg oats, Overberg oats, LS 35 stooling rye, LS 62 stooling rye and Cloc 1 Triticale) were planted on six planting dates (05 April, 04 May, 06 June, 20 July, 20 August and 26 September). Five cutting treatments were applied on Dewageningsdrift:  First cut 8 weeks after planting and after that re-growth every six weeks (Ct 8),  First cut 10 weeks after planting and after that re-growth every six weeks (Ct 10),  First cut 12 weeks after planting and after that re-growth cut every six weeks (Ct 12),  First cut 14 weeks after planting and after that re-growth cut every six weeks (Ct 14),  First cut when more than 50% of plants were in the reproduction stage (RS). The same cultivars that were used at Dewageningsdrift were used on Nooitgedacht ADC. Only one planting date was applied here that was 02 February 2007. The cutting treatments differed also from that on Dewageningsdrift. Material was cut for the first time when it reached a grazing stage (± 50-60 cm high) and after that re-growth was measured four weeks. The main conclusions from the study were that, Witteberg oats has retained its nutritional value longer than other cultivars. LS 35 stooling rye was an early or short duration growing cultivar, if planted in February to April it will provide grazing early/Mid-winter. However it can also be planted in July to grow in spring. LS 62 stooling rye is a medium to long duration growing cultivar which optimum production period will be in late winter and spring. Witteberg oats is a medium/late producer and a long duration growing cultivar, thus if planted early (April) it can provide grazing until late winter. Overberg oats is an early/med long duration growing type, if planted in April it will produce mid-winter, planted in May to July it will produce late winter and planted in August it will provide spring grazing. Cloc 1 triticale is a long duration growing type. It will produce late winter when planted in April to July and in spring when planted in August/September.

The objective of this thesis was to determine the potential impact on groundwater quality as a result of the release of leachate from livestock mortality burial for three species of livestock: swine, bovine and poultry. Specific objectives were to:<p> 1.Characterize the chemical composition of leachate in livestock mortality burial pits for three species: bovine, swine and poultry; and<p> 2.Evaluate the potential environmental impact of livestock burial through groundwater transport modelling.<p> A two part program was followed to achieve these objectives. The first portion involved construction of lined burial pits complete with leachate collection systems. Poultry (1300kg), swine (5900kg) and bovine (9750kg) carcasses were each placed in separate pits and the pits covered with plastic liner material and then approximately one meter of earthen cover. The pits were sampled for leachate chemical analysis at 2 weeks, 1 month, 2 months, 4 months, 8 months, 14 months and 25 months post burial. The second portion involved using the chemical analysis results from first portion and two groundwater modeling software packages (CTRAN and PHREEQC) to characterize the leachate and evaluate the potential this material could have on groundwater resources adjacent to burial pits.<p> The results indicated that livestock mortality leachate contains, on average, after two years of decomposition, concentrations of 12,600 mg/L of ammonium-N, 34,600 mg/L alkalinity (as bicarbonate), 2,600 mg/L chloride, 3,600 mg/L sulphate, 2,300 mg/L potassium, 1,800 mg/L sodium, 1,500 mg/L phosphorus along with relative lesser amounts of iron, calcium and magnesium. Maximum values for the major ions were up to 50% higher than the average in some instances. The pH of the leachate was near neutral. In comparison to earthen manure storages and landfills, the strength of the leachate was 2-4 times higher.<p> To properly characterize the leachate chemistry, speciation of the mortality leachate was performed using PHREEQC. This speciation provided evidence of phosphate compounds precipitating from solution, as well as significant amounts of phosphoric acids (0.03 mol/L). Relatively high concentrations of ammonium sulphate also formed and due to the negative charge, allow for potentially 300 mg-N/L to transport conservatively. In comparison to naturally occurring groundwater, activities of bicarbonate, sulphates, phosphates and other minerals were many orders of magnitude higher than concentrations present in groundwater.<p> Preliminary simulations were created with two software packages, Geo-Slope CTRAN and PHREEQC to simulate transport of the leachate for three different soil conditions. The Geo-Slope model models a conservative contaminant, while the PHREEQC model involves geochemical speciation and contaminant transport including ion exchange occurring along the pathway. Transport through a low permeable soil (K=1 x 10-10 m/s) was dominated by diffusion allowing unattenuated leachate to transport a distance of approximately three meters in 50 years. The moderately permeable soil situation (K=1 x 10-9 m/s) produced a transport depth of six meters with an approximate concentration of the tracer thirty to forty percent of initial concentration in 50 years. In a highly permeable soil (K=1 x 10-8 m/s), transport reached a depth of 10 meters in 10 years with approximately forty percent of initial concentration. The PHREEQC transport model demonstrated a highly concentrated calcium and magnesium plume forming in front of the ammonium plume suggesting ion exchange and attenuation of ammonium.<p> In the occurrence of a mass mortality event, regulators in Canada have decided to employ a trench burial system. Trenches could be created using on-the-farm equipment such as backhoes to obtain approximate trench dimensions of 2 m wide and 4 m deep. To assess the impact of multiple trenches and their appropriate spacing, models were created with Geo-Slope CTRAN to evaluate the effects on trench spacing. It was determined through these models that a minimum 10 m separation distance would provide a potential contaminant plume maximum soil contact and no trench-to-trench impact.<p> To further evaluate the potential impact of livestock burial leachate, mass loading into an aquifer was evaluated for a moderately permeable soil (K=1 x 10-9 m/s) for a mass mortality event in a 10,000 head feedlot. Disposal consisted of ten 200 m trenches with a 10 m separation distance. Disposal covered 2.2 hectares and provided a mass loading of ammonium to an aquifer 10 m below of 950 kg/year after 50 years and increasing from 50 years until the peak concentration of the plume reached the aquifer. At this loading rate, nitrogen concentrations exceed drinking water standards 10-15 times.

Science, technology, engineering, and mathematics (STEM) education is intended to provide students with a cross-subject, contextual learning experience. In order to more fully prepare our nation's students for entering the globally competitive workforce, STEM integration allows students to make connections between the abstract concepts learned in core subject classrooms and real-world situations. FFA and 4-H programs, by nature, are intended to provide students with hands-on learning opportunities where abstract core subject principles can be applied and more fully understood. Junior livestock projects through FFA and 4-H can provide rich connections for students between what they learn in school and how it is applied in the real world through their livestock project. Using a modified Delphi technique, this study identified STEM concepts associated with junior livestock projects. The study also examined whether STEM concepts should be integrated into the supervision of junior livestock projects and identified barriers which would prevent the incorporation of STEM concepts into local 4-H and FFA programming and instruction. The experts identified several (13 of 19) STEM concepts associated with junior livestock projects, four reasons local 4-H and FFA leaders/advisors should incorporate STEM concepts into their programming and instruction, and no barriers which would prevent local 4-H and FFA leaders/advisors from incorporating STEM concepts into their programming and instruction. This paper explores rationale regarding why STEM integration is important and makes recommendations for the integration of STEM concepts into the supervision of junior livestock projects.

Canadian agriculture trade with the United States, specifically trade in livestock and livestock commodities, has flourished under the NAFTA regime. However, the benefits of this trade liberalization have hidden environmental costs that seldom get noticed or accounted. The purpose of this research was to evaluate the hidden cost on water resources by first assessing the virtual water content (VWC) of various types of livestock and livestock products and then quantifying the virtual water flow (VWF) related to trade in livestock and its products between Canada and United States. The study also examined the North American Free Trade Agreement (NAFTA) and evaluated its implications for Canadian water resources. The research was conducted in three parts. First, the background literature on NAFTA was studied and trade data were collected to understand the NAFTA regime and study the impacts on Canadian exports of livestock and livestock products from the 1990s. The trade data were collected from provincial agricultural ministries and Statistics Canada. Secondly, datasheets were created to calculate the VWC in the various categories of animals and ultimately to estimate VWF between the two countries. Finally, Alberta and Ontario were chosen as case study areas to investigate localized impacts on water resources due to trade under NAFTA. The research results indicate that there is a large difference in the amount of VW being transferred through livestock and livestock commodities from Canada to the U.S. The average difference in trade has been calculated to be 3.6 billion m3 per year. This makes Canada a net exporter of virtual water to the U.S. A closer look at the trade patterns reveals that the U.S. imports mostly water-intensive commodities like cattle and cattle commodities, while it exports mostly less-water intensive commodities like chicken and mutton. By eliminating numerous trade barriers, the agreement has allowed competitive market forces to play a more dominant role in determining agricultural trade flows between the two countries. NAFTA has been criticized and contested at different levels for encouraging bulk water export from Canada to the U.S. What has not received attention in this debate is that water is also being exported in other forms, i.e., the virtual form. The hidden environmental, costs (for the exporting countries) or benefits (to the importing countries) are not reflected in the pricing of agricultural commodities. NAFTA’s mandate for the expansion of trade and investment through the removal of all trade barriers between the two countries is encouraging increased VW trade. This trade, if overlooked, can have deleterious impacts on the water resources of Canada.

Canadian agriculture trade with the United States, specifically trade in livestock and livestock commodities, has flourished under the NAFTA regime. However, the benefits of this trade liberalization have hidden environmental costs that seldom get noticed or accounted. The purpose of this research was to evaluate the hidden cost on water resources by first assessing the virtual water content (VWC) of various types of livestock and livestock products and then quantifying the virtual water flow (VWF) related to trade in livestock and its products between Canada and United States. The study also examined the North American Free Trade Agreement (NAFTA) and evaluated its implications for Canadian water resources. The research was conducted in three parts. First, the background literature on NAFTA was studied and trade data were collected to understand the NAFTA regime and study the impacts on Canadian exports of livestock and livestock products from the 1990s. The trade data were collected from provincial agricultural ministries and Statistics Canada. Secondly, datasheets were created to calculate the VWC in the various categories of animals and ultimately to estimate VWF between the two countries. Finally, Alberta and Ontario were chosen as case study areas to investigate localized impacts on water resources due to trade under NAFTA. The research results indicate that there is a large difference in the amount of VW being transferred through livestock and livestock commodities from Canada to the U.S. The average difference in trade has been calculated to be 3.6 billion m3 per year. This makes Canada a net exporter of virtual water to the U.S. A closer look at the trade patterns reveals that the U.S. imports mostly water-intensive commodities like cattle and cattle commodities, while it exports mostly less-water intensive commodities like chicken and mutton. By eliminating numerous trade barriers, the agreement has allowed competitive market forces to play a more dominant role in determining agricultural trade flows between the two countries. NAFTA has been criticized and contested at different levels for encouraging bulk water export from Canada to the U.S. What has not received attention in this debate is that water is also being exported in other forms, i.e., the virtual form. The hidden environmental, costs (for the exporting countries) or benefits (to the importing countries) are not reflected in the pricing of agricultural commodities. NAFTA’s mandate for the expansion of trade and investment through the removal of all trade barriers between the two countries is encouraging increased VW trade. This trade, if overlooked, can have deleterious impacts on the water resources of Canada.

The objective of this thesis was to determine the potential impact on groundwater quality as a result of the release of leachate from livestock mortality burial for three species of livestock: swine, bovine and poultry. Specific objectives were to:<p> 1.Characterize the chemical composition of leachate in livestock mortality burial pits for three species: bovine, swine and poultry; and<p> 2.Evaluate the potential environmental impact of livestock burial through groundwater transport modelling.<p> A two part program was followed to achieve these objectives. The first portion involved construction of lined burial pits complete with leachate collection systems. Poultry (1300kg), swine (5900kg) and bovine (9750kg) carcasses were each placed in separate pits and the pits covered with plastic liner material and then approximately one meter of earthen cover. The pits were sampled for leachate chemical analysis at 2 weeks, 1 month, 2 months, 4 months, 8 months, 14 months and 25 months post burial. The second portion involved using the chemical analysis results from first portion and two groundwater modeling software packages (CTRAN and PHREEQC) to characterize the leachate and evaluate the potential this material could have on groundwater resources adjacent to burial pits.<p> The results indicated that livestock mortality leachate contains, on average, after two years of decomposition, concentrations of 12,600 mg/L of ammonium-N, 34,600 mg/L alkalinity (as bicarbonate), 2,600 mg/L chloride, 3,600 mg/L sulphate, 2,300 mg/L potassium, 1,800 mg/L sodium, 1,500 mg/L phosphorus along with relative lesser amounts of iron, calcium and magnesium. Maximum values for the major ions were up to 50% higher than the average in some instances. The pH of the leachate was near neutral. In comparison to earthen manure storages and landfills, the strength of the leachate was 2-4 times higher.<p> To properly characterize the leachate chemistry, speciation of the mortality leachate was performed using PHREEQC. This speciation provided evidence of phosphate compounds precipitating from solution, as well as significant amounts of phosphoric acids (0.03 mol/L). Relatively high concentrations of ammonium sulphate also formed and due to the negative charge, allow for potentially 300 mg-N/L to transport conservatively. In comparison to naturally occurring groundwater, activities of bicarbonate, sulphates, phosphates and other minerals were many orders of magnitude higher than concentrations present in groundwater.<p> Preliminary simulations were created with two software packages, Geo-Slope CTRAN and PHREEQC to simulate transport of the leachate for three different soil conditions. The Geo-Slope model models a conservative contaminant, while the PHREEQC model involves geochemical speciation and contaminant transport including ion exchange occurring along the pathway. Transport through a low permeable soil (K=1 x 10-10 m/s) was dominated by diffusion allowing unattenuated leachate to transport a distance of approximately three meters in 50 years. The moderately permeable soil situation (K=1 x 10-9 m/s) produced a transport depth of six meters with an approximate concentration of the tracer thirty to forty percent of initial concentration in 50 years. In a highly permeable soil (K=1 x 10-8 m/s), transport reached a depth of 10 meters in 10 years with approximately forty percent of initial concentration. The PHREEQC transport model demonstrated a highly concentrated calcium and magnesium plume forming in front of the ammonium plume suggesting ion exchange and attenuation of ammonium.<p> In the occurrence of a mass mortality event, regulators in Canada have decided to employ a trench burial system. Trenches could be created using on-the-farm equipment such as backhoes to obtain approximate trench dimensions of 2 m wide and 4 m deep. To assess the impact of multiple trenches and their appropriate spacing, models were created with Geo-Slope CTRAN to evaluate the effects on trench spacing. It was determined through these models that a minimum 10 m separation distance would provide a potential contaminant plume maximum soil contact and no trench-to-trench impact.<p> To further evaluate the potential impact of livestock burial leachate, mass loading into an aquifer was evaluated for a moderately permeable soil (K=1 x 10-9 m/s) for a mass mortality event in a 10,000 head feedlot. Disposal consisted of ten 200 m trenches with a 10 m separation distance. Disposal covered 2.2 hectares and provided a mass loading of ammonium to an aquifer 10 m below of 950 kg/year after 50 years and increasing from 50 years until the peak concentration of the plume reached the aquifer. At this loading rate, nitrogen concentrations exceed drinking water standards 10-15 times.

Thesis (M.S.)--University of Tennessee, Knoxville, 2004. / Title from title page screen (viewed Jan. 12, 2005). Thesis advisor: Randol G. Waters. Document formatted into pages (vii, 63 p.). Vita. Includes bibliographical references (p. 46-50).