Diss. (sammanfattning) Göteborg : Göteborgs universitet, 2004. / Härtill 4 uppsatser.

Three greenhouse and two field plot experiments were conducted to determine the influence of seaweed extract and other plant growth regulators on forage quality and persistence of endophyte-infected (Acremonium coenophialum Morgan-Jones and Garns) and endophyte-free tall fescue (Festuca arundinacea Schreb.). The influence of plant growth regulators on forage quality of endophyte-infected tall fescue and performance of wether lambs was evaluated in two grazing trials. Greenhouse and field experiments were randomized block designs. Results from greenhouse studies varied but indicated increased (P ≤ .05) root strength and decreased (P ≤ .01) pressure required to extract moisture from leaves due to treatment. Analysis from greenhouse and field studies indicated little effect on fiber components, nonstructural carbohydrates, and crude protein. In tall fescue grazed by lambs, pyrrolizidine alkaloid concentration was decreased (P ≤ .05) between seaweed extract treatments. Ergovaline tended (P ≤ .08) to decrease in all treated forage and was 4.26, 3.78, 3.59, and 3.48 µg g⁻¹ (S.E. = .28) for control, 1703, and 3406 g seaweed extract ha⁻¹, and 19.1 L VTMix ha⁻¹, respectively. Lambs grazing treated forage in July had increased (P ≤ .05) ADG (.03 vs a mean of .11 kg gain per d for control vs treatments, respectively). Linear trends (P .13) of increased serum vitamin A and increased (P ≤ .10) whole blood Se due to seaweed extract treatment were observed. Serum Se values were 241, 264, and 274 ng/ml (S.E. = 13) for control, 1703, and 3406 g seaweed extract ha⁻¹, respectively. Results indicated that plant growth regulators may have potential to increase plant persistence and decrease toxicity of tall fescue. / M.S.

Master of Science

Master of Science

Master of Urban and Regional Planning

Master of Science

Master of Science

Energy recovery from the anaerobic treatment of crab processing wastewater was investigated. Biogas from two laboratory-scale, upflow anaerobic filters (Systems A and B) was collected and analyzed to determine percent by volume composition of methane (CH₄), carbon dioxide (CO₂), and hydrogen sulfide (H₂S). Biogas produced by System A (upflow anaerobic bed filter) produced biogas averaging 68, 28, and 1.5 % CH₄, CO₂, and HS, respectively. System A average gas production ranged from 6.3 to 15.8 liters per day (L/d) (6.6 to 10.0 L gas/L feed) for COD reductions ranging from 11,000 to 27,000 milligrams per day (mg/d) and COD loadings ranging from 16,700 to 43,600 mg/d. System B (upflow anaerobic packed filter) produced biogas averaging 68, 28, and 1.4 % CH₄, CO₂, and H₂S, respectively. System B average gas production ranged from 7.5 to 19.5 L/d (7.1 to 11.9 L gas/L feed) for COD reductions ranging from 11,700 to 28,700 mg/d and COD loadings ranging from 16,100 to 48,500 mg/d. A pilot-scale biogas collection system was constructed to collect, treat (remove H₂S), store, and utilize the biogas produced by an anaerobic/aerobic crab processing wastewater treatment system treating between 15 and 30 gallons per day (gpd). Biogas was produced by a 190 gallon upflow anaerobic bed filter and a 190 gallon anaerobic clarifier operated in series. Preliminary results indicated biogas production rates comparable to maximum average gas production rates of the laboratory-scale systems at approximately 10 L gas/L feed. Biogas was stored in a 120 gallon tank at up to 12 pounds per square inch (psi) following removal of hydrogen sulfide. Biogas was then burned in a modified natural gas hot water heater to produce heated water for maintaining the anaerobic reactors at 35°C. / Master of Science

Estimates of the social benefits of integrated pest management (IPM) are fundamental to an informed assessment of the value of public expenditures for IPM research and extension. This study evaluates a subset of the potential social benefits if IPM adoption - reductions in the environmental and human health costs of pesticide use. A methodology is developed to estimate the environmental and human health costs of pesticide use associated with the production of any crop. The cost estimates for production under "conventional" (i.e. non-IPM) pest management are compared to the cost estimates associated with production under an IPM program to generate estimates of the environmental and human health benefits of IPM adoption. The development of the methodology resulted in: (1) a new algorithm for assigning levels of IPM adoption to agricultural producers; (2) the design and administration of a contingent valuation survey to estimate society's willingness to pay (WTP) to avoid pesticide related risks to the environment and human health; (3) a new technique for detecting payment vehicle bias in contingent valuation surveys; (4) a set of criteria for assigning to pesticidal active ingredients (a.i.) levels of relative risk that a. i. 's pose to eight environmental and human health categories; and (5) the assignment of relative risk levels to more than one hundred pesticidal active ingredients. All of these results are directly applicable to other studies of this kind. The analysis of Virginia apple production results in several recommendations regarding the design of future chemical use surveys conducted by United States Department of Agriculture. The analysis of the Early Leaf Spot Advisory system (ELSA) for Virginia peanut production estimates the environmental and human health benefits of ELSA to be approximately $840,000 per year. / Master of Science

A dimensional analysis approach was applied to derive a general volume equation for a tree. A taper equation compatible with the general volume equation was developed. Data from loblolly pine trees grown in natural stands in the Coastal Plain of North Carolina and the Coastal Plain and Piedmont areas of Virginia were used to estimate the parameters for these volume equations. A dimensionally compatible volume equation is shown to be a better equation for estimation of the volume of loblolly pine trees and can be applied for the estimation of total volume. The taper equation can be applied to predict the diameter for any specified height and to predict height for any top diameter limit. The volume between any two points on the tree bole can be calculated by integration of the taper equation. / Master of Science