This dissertation investigates the relationship between greenhouse gas emissions, international trade, and economic growth as per capita incomes increase. The first chapter uses a Suits Index to illustrate the degree of pollution concentration among countries at different levels of per capita Gross Domestic Product. It also analyzes the collective progressivity of pollution and compares countries with similar levels of per capita income to monitor emissions as countries move up the income scale. Pollution is found to be concentrated among the lower income countries for all sources of greenhouse gas emissions including nitrous oxide, methane, and carbon dioxide. Emissions are more concentrated among poorer countries when the source of pollution is the agricultural sector. Poor countries account for much more pollution than would be expected from their levels of economic activity and well being. Chapter 2 uses an Environmental Kuznets Curve model to investigate the relationship between methane and nitrous oxide emissions from industrial and agricultural sources and per capita income from 1970 to 2005 for 157 countries. A fixed effect panel regression model is used to capture technological change, economies of scale, composition effects, and trade effects on per capita pollution. Results suggest that an inverted U-shape characterizes the relationship between per capita income and both industrial and agricultural emissions, but that agricultural turning points will occur later and at a higher per capita pollution than industrial turning points in the absence of regulation. In Chapter 3, a dynamic fixed effect panel data regression model is used to explore the relationship between pollution emissions and several related economic factors. An alternative simultaneous equation model is developed to allow for both a direct effect of trade on environmental damage via changes in relative prices and an indirect effect of trade on income growth via liberalization. Human capital, physical capital, labor and the catch-up term are expected to affect the growth of the economy positively and significantly. The extent of their economic significance will depend on the level of economic activity of the countries analyzed. Direct and indirect effects of openness on pollution are ambiguous and enter insignificantly or have a small effect on pollution across all country groups. Concerns about trade liberalization on environmental degradation from GHG seem unjustified.

The Canadian greenhouse industry is challenged by high operating costs as the natural gas price has been increasing and fluctuating over the past few years. Natural gas is the primary energy used by the greenhouse industry to generate heat and carbon dioxide (CO₂) to enhance the crop productivity. There are concerns about the global warming effect caused by natural gas usage as it is a non-renewable energy. Therefore, the greenhouse industry is considering the use of wood biomass, mainly wood pellets and wood residue, to decrease the natural gas demand. However, the long-term economic value, the air quality emission, and the long-term resource availability are the main barriers for the industry to convert into wood biomass boiler. The main objectives of this study are, to evaluate the economic feasibility of using wood biomass for the greenhouse heating application, to analyze the associated impacts of the technical and economical changes, and to determine the optimal biomass mix with the consideration of emission limits and resources availability constraints. Specific case studies will be considered in this research to achieve the mentioned objectives. The results of the techno-economic analysis showed positive net present value (NPV) for the four cases considered: using wood pellets or wood residue boiler, with or without an electrostatic precipitator (ESP), to generate portion of heat demand for a greenhouse. Although the decision making would be affected by the price changes and the size of a greenhouse, a positive NPV was determined from a pure economic view point. Wood biomass combustion could reduce over 3,000 tonnes of CO₂ equivalent greenhouse gases annually. Sensitivity analyses indicated that wood biomass attractiveness would increase with higher natural gas prices or larger energy contributions from wood biomass. The optimization study suggests a feasible biofuels mix for the case study of a 2 ha flower greenhouse and a 7.5 ha vegetable greenhouse. The model was solved considering the inclusion of an ESP system to ensure the air quality limits were satisfied. The optimal result was compared to an existing 2 ha flower greenhouse and revealed almost 20% reduction on the total fuel cost per year.

The Canadian greenhouse industry is challenged by high operating costs as the natural gas price has been increasing and fluctuating over the past few years. Natural gas is the primary energy used by the greenhouse industry to generate heat and carbon dioxide (CO₂) to enhance the crop productivity. There are concerns about the global warming effect caused by natural gas usage as it is a non-renewable energy. Therefore, the greenhouse industry is considering the use of wood biomass, mainly wood pellets and wood residue, to decrease the natural gas demand. However, the long-term economic value, the air quality emission, and the long-term resource availability are the main barriers for the industry to convert into wood biomass boiler. The main objectives of this study are, to evaluate the economic feasibility of using wood biomass for the greenhouse heating application, to analyze the associated impacts of the technical and economical changes, and to determine the optimal biomass mix with the consideration of emission limits and resources availability constraints. Specific case studies will be considered in this research to achieve the mentioned objectives. The results of the techno-economic analysis showed positive net present value (NPV) for the four cases considered: using wood pellets or wood residue boiler, with or without an electrostatic precipitator (ESP), to generate portion of heat demand for a greenhouse. Although the decision making would be affected by the price changes and the size of a greenhouse, a positive NPV was determined from a pure economic view point. Wood biomass combustion could reduce over 3,000 tonnes of CO₂ equivalent greenhouse gases annually. Sensitivity analyses indicated that wood biomass attractiveness would increase with higher natural gas prices or larger energy contributions from wood biomass. The optimization study suggests a feasible biofuels mix for the case study of a 2 ha flower greenhouse and a 7.5 ha vegetable greenhouse. The model was solved considering the inclusion of an ESP system to ensure the air quality limits were satisfied. The optimal result was compared to an existing 2 ha flower greenhouse and revealed almost 20% reduction on the total fuel cost per year.

Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 82-88).

The Canadian greenhouse industry is challenged by high operating costs as the natural gas price has been increasing and fluctuating over the past few years. Natural gas is the primary energy used by the greenhouse industry to generate heat and carbon dioxide (CO₂) to enhance the crop productivity. There are concerns about the global warming effect caused by natural gas usage as it is a non-renewable energy. Therefore, the greenhouse industry is considering the use of wood biomass, mainly wood pellets and wood residue, to decrease the natural gas demand. However, the long-term economic value, the air quality emission, and the long-term resource availability are the main barriers for the industry to convert into wood biomass boiler. The main objectives of this study are, to evaluate the economic feasibility of using wood biomass for the greenhouse heating application, to analyze the associated impacts of the technical and economical changes, and to determine the optimal biomass mix with the consideration of emission limits and resources availability constraints. Specific case studies will be considered in this research to achieve the mentioned objectives. The results of the techno-economic analysis showed positive net present value (NPV) for the four cases considered: using wood pellets or wood residue boiler, with or without an electrostatic precipitator (ESP), to generate portion of heat demand for a greenhouse. Although the decision making would be affected by the price changes and the size of a greenhouse, a positive NPV was determined from a pure economic view point. Wood biomass combustion could reduce over 3,000 tonnes of CO₂ equivalent greenhouse gases annually. Sensitivity analyses indicated that wood biomass attractiveness would increase with higher natural gas prices or larger energy contributions from wood biomass. The optimization study suggests a feasible biofuels mix for the case study of a 2 ha flower greenhouse and a 7.5 ha vegetable greenhouse. The model was solved considering the inclusion of an ESP system to ensure the air quality limits were satisfied. The optimal result was compared to an existing 2 ha flower greenhouse and revealed almost 20% reduction on the total fuel cost per year. / Forestry, Faculty of / Graduate

Thesis (M.Env.Sc.)--University of Adelaide, Mawson Graduate Centre for Environmental Studies, 1999. / Bibliography: leaves 120-124.

Thesis (MScAgric)--University of Stellenbosch, 2005. / Bibliography. Also available via the Internet.

Thesis (MSc)--Stellenbosch University, 2005. / ENGLISH ABSTRACT: Various researchers have determined that salinity causes several kinds of damage to plants such as germination inhibition, metabolic disturbances, yield reduction and quality losses. However, the severity of salt damage has been found to be dependent on the cultivar, level of salinity, period of exposure to salinity, and the growth stage of the plant. An understanding of the severity of salinity and its potential negative impacts on crops is essential to optimise production. Knowledge of seed vigour, expressed as germination percentage and germination rate at the optimum temperature for germination, would provide growers with valuable information to measure and compare the viability of seed lots. A study was done where fresh and aged seeds of two watermelon cultivars were investigated in germination tests under laboratory conditions at four salinity levels and five temperature regimes. The best germination was achieved at 4 mS cm-1 for both cultivars, Odem and Paladin. At 8 mS cm-I, the germination percentage for Paladin was 31% better than for Odem. The germination time for aged Odem seeds was significantly delayed at this EC 8 level but ageing of Paladin seeds had no detrimental effect at this EC level. Paladin germinated significantly better than Odem at the relatively low temperature range of I5-20°C, indicating that it is well-adapted for early planting. A new plant growing system, using vertical training of two shoots was tested in a greenhouse, aiming to optimise the growth regulating capabilities of this crop environment. Traditional watermelons are open-field planted in rows at low densities. Even with this plant spacing, by harvesting time the vines are spread in such a way that the foliage laterally covers the inter-row spacing, making cultivation practices such as spraying, weeding and harvesting difficult and almost impossible. The production of greenhouse crops is advantageous, but involves a number of cultural inputs and techniques for optimum yields. The effects of plant pruning systems and salinity levels on watermelon cultivars (Odem and Paladin) in a low-cost greenhouse were studied using a drain-to-waste fertigation system. Changing the nutrient solution from a low salinity level (EC 4 mS cm1) during vegetative growth to EC 4 mS cm-I after pollination, did not reduce fruit mass, but significantly increased the sugar yield of Odem, the icebox-type cultivar. Excessive pruning (less leaves per shoot) was more efficient with low salinity levels than at a high salinity level. Moderate pruning (more leaves per shoot) represented a good system, producing fruits of lesser weight and acceptable quality. / AFRIKAANSE OPSOMMING: Verskeie navorsers het reeds die skadelike gevolge van brak toestande op ontkieming, plant metabolisme, opbrengs en kwaliteit van gewas plante ondersoek. Die omvang van die skade kan deur kultivars, die konsentrasie soute, die periode van blootstelling asook plante se groeistadium bepaal word. 'n Goeie begrip van die potensiële skadelikheid van hoë sout konsentrasies op gewasse is nodig om produksie te optimaliseer. Inligting oor die kiemkragtigheid van saad, uitgedruk as die persentasie ontkieming asook die ontkiemingstempo, is vir kwekers nodig ten einde te verseker dat goeie saad gebruik kan word. 'n Ondersoek is gedoen waar vars asook verouderde saad van twee waatlemoen kultivars onder laboratorium toestande by vier sout peile en vyf temperature ontkiem is. Die beste ontkieming vir beide kultivars, Odem en Paladin, is gevind waar die elektriese geleiding (Eï,') 4 mS cm-1 was. Teen 8 mS cm-1 was die persentasie ontkieming vir Paladin 31% beter as vir Odem. Veroudering van Odem saad het 'n betekenisvol swakker ontkiemingstempo met'n Ee van 8 mS cm-1 getoon terwyl verouderde Paladin saad nie by hierdie Ee swakker vertoon het nie. Paladin het by die relatief lae temperatuur sone van 15-20oe betekenisvol beter as Odem saad ontkiem wat daarop dui dat dit vir vroeë aanplantings geskik is. 'n Nuwe produksiestelsel, waar twee lote per plant vertikaal in 'n V-vorm opgelei is, is in 'n kweekhuis getoets in 'n poging om die groeiregulerende potensiaal van so 'n omgewing te optimaliseer. Waatlemoene word tradisioneel in rye teen 'n lae plantdigtheid in veldaanplantings verbou. Met so 'n praktyk ontwikkel daar soveel ranke tussen die rye dat praktyke soos onkruid beheer, plaagbeheer en oes bemoeilik word. Die produksie van gewasse in kweekhuise hou voordele in maar 'n aantal insette en spesiale tegnieke is nodig vir optimum opbrengs. Die invloed van snoeipraktyke en soutpeile is met twee waatlemoen kultivars (Odem en Paladin) in 'n lae-koste kweekhuis ondersoek deur 'n sisteem te gebruik waar voedingsoplossings in vry dreinerende sakke met saagsels gedrup is. Waar die Ee van die voedingsoplossing voor vrugset 2 mS cm-1 was en toe vir die periode van vrugontwikkeling tot 4 mS cm-1 verhoog is, het geen vrugverkleining by Odem gevolg nie terwyl die suikeropbrengs wel verhoog het. Oormatige verwydering van blare was minder skadelik met 'n lae EC as waar die EC hoog was. 'n Matige snoeiproses met meer blare per loot, het 'n goeie produksie van aanvaarbare vruggrootte en 'n goeie kwaliteit verseker.

Thesis (PhD)--University of South Australia, 1997

Thesis (M.S.) in Resource Economics and Policy--University of Maine, 2008. / Includes vita. Includes bibliographical references (leaves 82-85).