Master of Science / Department of Agronomy / Scott A. Staggenborg / Current demand for ethanol production is stressing feedstock production. Previous research has shown sweet sorghum and photoperiod sensitive sorghum [Sorghum bicolor (L.) Moench] as viable feedstocks which may supplement or replace current feedstocks. Studies were conducted at two dryland locations in north central and northeast Kansas in 2008 and 2009 to determine the effects of cultivar, nitrogen fertilizer rate, plant density, and harvest date on sweet sorghum juice and biomass yields. The cultivar study indicated the cultivar ‘M81E’ generally had the greatest yield. Other cultivars were not well suited for this region. No significant results were found in the nitrogen rate trial, indicating sweet sorghum may be insensitive to nitrogen fertilizer applications. The plant density trial results indicated that sweet sorghum possess a great ability to compensate for plant spacing. No differences were found in juice yields across densities, and the only difference found in total dry biomass was at the highest plant density. Results from the harvest date study indicate that sweet sorghum harvest should be delayed until at least the grain soft dough stage and can be continued for at least 10 days after a killing freeze without a yield penalty. Delaying harvest allowed for an increase in total dry matter and fermentable carbohydrates without a decrease in juice yield. Two studies were conducted at two dryland locations in northcentral and northeast Kansas in 2008 and 2009 to determine the effects of plant density on photoperiod sensitive sorghum yields, with an additional study to determine the effects of winter weathering. Photoperiod sensitive sorghum was found to be similarly insensitive to plant density, with few differences found in total dry biomass yield. Yields were found to decrease significantly due to winter weathering. A final study was conducted to examine a variety of sorghums as biofuel feedstocks. Photoperiod sensitive sorghum yielded the greatest in 2008 while sweet sorghum yielded less. In 2009, sweet and photoperiod sensitive sorghum yielded less than the cultivar TAMUXH08001. Sweet sorghum yields are generally the greatest with ‘M81E’ and when harvested after soft dough. Yields of both sorghums are occasionally influenced by plant density.

Forage sorghum (Sorghum bicolor L. Moench) is one of the prospective crops that may be used to produce biofuels in the future. Therefore, it is of interest to find management practices that improve both the production of biomass yield and quality. This study presents observations of the effects different rates of nitrogen fertilization have on yield, tissue nitrogen content, and tissue quality measures such as ash, lignin, sucrose, xylans, cellulose and starch content, based on three years of field trials from the Brazos Bottom and one year of field trials from near China, Texas. Data for the quality components were obtained using near infrared spectroscopy, with the exception of tissue nitrogen which was determined by using the dry combustion method. This study has showed fertilizer nitrogen had a strong positive correlation with the tissue nitrogen of sorghum biomass. Changes in tissue quality in relationship with fertilizer nitrogen levels and tissue nitrogen concentration were also observed. Ash showed a strong positive and sucrose showed a strong negative correlation to both tissue nitrogen concentration and fertilizer nitrogen application. Similarly to sucrose, starch also decreased with higher nitrogen levels and lignin was found to increase slightly. The concentration of cellulose and xylans were very weakly affected by nitrogen application and nitrogen concentration.

There are over 3,700 active and decommissioned municipal solid waste (MSW) landfill sites located in Ontario (MOE, 1991). Under current legislation, these landfill sites must be rehabilitated to a defined end use when decommissioned. In Ontario, the primary prescribed end use of closed landfills is typically agriculture, and that end use can lead to food-consumer concerns, due to the perceived risk of potential contamination from legacy materials found in landfills. Converting these sites to produce biomass-energy crops instead of food crops could mitigate that concern and also help to avoid the current controversy with bioenergy-crop production on high-capability agricultural land. In this study, a 3.5-year field program with subsequent verification and analysis investigated and developed rehabilitation prescriptions using locally obtained topsoil and soil-forming materials (subsoil) to develop anthropogenic soil profiles on top of a sealed landfill cover (clay cap). These prescriptions provided crop productivity at least as good as, and generally better than, local agricultural soils. Mixed forages and biomass-specific crops (warm season grasses) were grown on these soils in replicated plot trials to evaluate the efficacy of a range of soil treatments. Following establishment of technical feasibility for site rehabilitation, economic modeling was conducted to determine the feasibility of using these anthropogenic soils for the production of forage crops, biofuel feedstock, and simple energy products at a scale consistent with typical landfill sites in Ontario. An economic model was developed to aid proponents in selecting appropriate rehabilitation methods and to assess potential bioenergy-crop outputs for their site. This study demonstrated that while it is technically feasible to rehabilitate these waste sites to produce agricultural crops and/or biofuel feedstock, the scale of typical landfill sites makes it very difficult to compete, from an economic perspective, with conventional energy sources. However, the diverted incoming materials, such as leaf and yard waste, compostable biosolids, and paper mill waste, can be used in the development of manufactured soil profiles for rehabilitation, significantly reducing rehabilitation costs and facilitating more cost-competitive production of agricultural and biomass feedstock crops. / Niagara Waste Systems Limited, a division of Walker Industries Holdings Limited, MITACS

This dissertation investigates three economic aspects of the climate change issue: optimal allocation of investment between adaptation and mitigation, impacts on a ground water dependent regional agricultural economy and effects on global food insecurity. This is done in three essays by applying mathematical programming. In the first essay, a modeling study is done on optimal temporal investment between climate change adaptation and mitigation considering their relative contributions to damage reduction and diversion of funds from consumption and other investments. To conduct this research, we extend the widely used Integrated Assessment Model?DICE (Dynamic Integrated Climate Economy) adding improved adaptation modeling. The model results suggest that the joint implementation of adaptation and mitigation is welfare improving with a greater immediate role for adaptation. In the second essay, the research focuses on the ground water dependent agricultural economy in the Texas High Plains Region. A regionally detailed dynamic land allocation model is developed and applied for studying interrelationships between limited natural resources (e.g. land and groundwater), climate change, bioenergy demands and agricultural production. We find out that the effect varies regionally across hydrologically heterogeneous regions. Also, water availability has a substantial impact on feedstock mix. In terms of biofuel feedstock production, the model results show that limited water resource cannot sustain expanded corn-based ethanol production in the future. In the third essay, a Computable General Equilibrium (CGE) model is applied in an attempt to study potential impacts of climate change on global food insecurity. Our results show that climate change alters the number of food insecure people in a regionally different fashion over time. In general, the largest increase of additional food insecure population relative to the reference case (no climate change) is found in Africa and South Asia, while most of developed countries will benefit from climate change with a reduced proportion of food insecure population. In general, climate change affects world agricultural production and food security. Integrated adaptation and mitigation strategy is more effective in reducing climate change damages. However, there are synergies/trade-offs between these two options, particularly in regions with limited natural resources.