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The Earth's climate system is driven by varying insolation from the Sun. The dominant variations in insolation are at 23 and 40 thousand year periods, yet for the past million years the Earth's climate has glacial cycles at approximately 100 kyr periodicity. These cycles are a coupled variation in temperature, ice volume, and atmospheric CO2. Somehow the Earth system's collective response to 23 and 40 kyr insolation forcing produces 100 kyr glacial-interglacial cycles. Generally it has been assumed that the causative mechanisms are a combination of ice dynamics (high ice reflectivity controlling temperature) and ocean circulation (changing carbon partitioning between the deep ocean and the atmosphere, and heat transport to the poles). However, these proposed mechanisms have not yet resulted in a compelling theory for all three variations, particularly CO2. This thesis explores the role of volcanic CO2 emissions in glacial cycles. I calculate that glacial-driven sea level change alters the pressure on mid-ocean ridges (MORs), changing their CO2 emissions by approximately 10%. This occurs because pressure affects the thermodynamics of melt generation. The delay between sea level change and the consequent change in MOR CO2 emissions is several tens-of-thousands-of-years, conceptually consistent with a coupled non-linear oscillation that could disrupt glacial cycles from a 40 kyr mode to a multiple of that period. I develop an Earth system model to investigate this possibility, running for approximately one million years and explicitly calculating global temperatures, ice sheet configuration, and CO2 concentration in the atmosphere. The model is driven by insolation, with all other components varying in response (and according to their own interactions). This model calculates that volcanism is capable of causing a transition to ̃100 kyr glacial cycles, however the required average volcanic CO2 emissions are barely within the 95% confidence interval. Therefore it is possible for volcanic systems and glacial cycles to form a 100 kyr coupled oscillation.

The morphological and ecologicalevolution of middle-upper Eocene planktonic foraminiferal family Hantkeninidae is investigated in the context of the dramatic palaeoceanographic and climatic changes that marked the transition from Paleogene "greenhouse" to Neogene "icehouse" climatic conditions. Morphometric analysis proves that evolution in family Hantkeninidae was gradual but complex in detail with periods of relative stasis. Multiple lines of evidence demonstrate that Hantkenina evolved from planispiral clavate genus Clavigerinella and not, as was previously believed, from Pseudohastigerina micra. The ancestor of Clavigerinella was probably a low trochospiral form Paragloborotalia sp., which has been recognized for the first time in this study at a number of sites. Trends in chamber inflation, tubulospine angle and the position of the tubulospine on each chamber show the most dramatic evolutionary changes, indicating that these are the most useful characters for taxonomy. These morphological changes correlate well with known palaeoceanographic changes as well as the shift in hantkeninid ecology from a deep to a surface water habitat. Hantkeninids underwent pronounced adaptive evolution in depth habitats during the initial phase of the climatic transition. Lower middle Eocene forms lived in a cool deep-water environment within or below the oceanic thermocline and shifted to warmer surface waters in the late middle Eocene. They evolved in the low latitudes and were primarily. a tropical-subtropical group. The occurrence of Hantkenma australis at relatively high northerly and southerly latitudes during the middle Eocene may record a temporary expansion of warmer water conditions into these regions, possibly representing a hitherto unknown "hyperthermal" event. Clavigerinella is rare in middle Eocene open-ocean sequences but occasionally occurs in relative abundance in other localities (such as on continental margins and oceanic seamounts), suggesting that it was specialized for living in upwelling regions. A revised taxonomy of family Hantkeninidae is presented that reflects new understanding ofhantkeninid evolution. The reconstructed phylogeny demonstrates that the tubulospine-bearing genera Hantkenina and Cribrohantkenina represent a monophyletic clade. Multivariate analysis suggests that more than one morphological population existed at several times and that these may represent biological species. The results demonstrate that the hantkeninids are not merely passive recorders of ocean conditions but have instead evolved morphology and changed habitat in response to climate change.

Architecture, as a discipline, has the potential to serve as a catalyst for cultivating an awareness of our intrinsic connection to the Earth and the broader universe. However, in the contemporary world, architectural practices frequently tend to alienate us from the natural environment, compelling many of us to inhabit indoor spaces reliant on centralized utility systems. This reliance, in turn, exerts significant stress on the Earth's ecosystems. The essence of architecture should instead lie in its capacity to engage with the surrounding natural elements, including the sun, wind, earth, and rain, thereby prompting individuals to acknowledge their geographical and planetary context. By harnessing these natural forces at the local level, architectural structures could autonomously provide their occupants with essential resources such as energy, water, and sustenance throughout the year. This thesis embarks on an exploration of the feasibility of integrating these principles of passive design into architectural structures, with the overarching goal of imparting experiential learning opportunities to the broader public. Through this endeavor, architecture can transcend its conventional role and emerge as a conduit for disseminating knowledge and awareness about sustainable living practices. Ultimately, this reimagined role for architecture can play a pivotal part in catalyzing the ongoing human evolution towards enhanced health and resilience, both as individuals and as a species.

Growing population demand and challenges brought on by climate change have spurred the need for more resilient fruit and vegetable supply chains. One agricultural technology of significant interest is the use of greenhouses for food production. Greenhouses create a stable and adaptable environment for crops such as tomatoes to grow year-round. Fresh tomatoes are the second most consumed vegetable per capita in U.S. diets, currently averaging 20.7 pounds. The growing consumption of fresh tomatoes has been the result of increasing cultural diversity in the United States. To meet the growing demand, Venlo-type greenhouses have been frequently used by growers. It provides an economical solution to produce multiple crops in various climate environments while withstanding severe weather conditions. While there have been many studies and advancements in using greenhouse technology to grow tomatoes in Europe, production has yet to be analyzed in the U.S. This study seeks to fill the gap of greenhouse tomato production by simulating growing scenarios using the openly accessible Modelica Greenhouse Library in 10 select locations across the mainland USA. Two growing scenarios were explored, a base case without CO2 enrichment and a CO2+ case with a continuous flow of CO2 being externally supplied to the system. All simulations had yields above 3-8 kg/m2/yr, which is expected of field-grown tomatoes. However, a few locations were below the expected range of 50-80 kg/m2/yr yield for greenhouse-grown tomatoes. CO2 enrichment in most cases resulted in increased fresh weight yield, reduced the use of resources which improved Product Water Use (PWU), Electrical and Thermal Energy Efficiency. Factors influencing the model such as Temperature, Supplemental Lighting, and CO2 enrichment were discussed.

Abstract: The energy consumption of greenhouse in cold regions, especially for the space heating, is still large and needs to be diminished either by reducing heat loss or by increasing the percentage of renewable energy usage. In order to predict the performance of different energy-saving designs, a greenhouse model with better accuracy and reduced complexity is needed. The main objectives of this paper are: 1. give a comprehensive review about the energy-saving design and operation strategies of greenhouses from previous studies. 2. provide detailed descriptions about important parameters of plants that should be used in greenhouse modelling. 3. develop a simplified greenhouse modelling method. 4. test three advanced design concepts: insulated north wall, cyclic lighting, transparent and vertical ceiling. The concepts and some other background information of plants’ parameters are given, and the relationships between these parameters and greenhouse modelling are explained. Before building the mathematical models, the thermal networks were simplified by dividing a greenhouse into three kinds of areas: middle, edge, and corner areas. The corner areas were not modelled because of their small proportion. When compared to the conventional ways of doing greenhouse modelling, the difficulty of the new modelling method is diminished by dividing a complex greenhouse thermal network into simpler subnetworks, which can be combined to form a complete network. In addition, the accuracy of new modelling method is also higher, since the interior air is modelled in more than one control volumes in middle and edge areas within a greenhouse, and the air node is separated from the plant node. The modelled results showed that the insulated north wall gave rise to a significant increase in air temperature (around 3.5 ℃) and resulted in greatest thermal energy saving.

Annually, nearly 1.5 million tons of sediments are dredged from Lake Erie, Ohio. The main method of dredged sediment disposal is open lake disposal. Open lake disposal poses a threat to water quality by re-suspending nitrogen and phosphorus-rich sediments. The Ohio State Senate passed a bill to prohibit the practice of open water disposal after July 2020 and recommends finding alternatives uses of the dredged sediment. One alternative is to use the sediment as an amendment for farm soil. This research aimed to measure the health of soil amended with various dredged sediment ratios, determine nutrient dynamics when the soil blends were subjected to induced storm-events, and quantify the effect of dredged sediment on soybean belowground biomass and yield. We used de-watered dredged sediment from the Great Lakes Dredged Material Center for Innovation and farm soil from a legacy phosphorous (P) farm site in Oregon, Ohio. Soil analysis was conducted on the two soils for baseline data. The soils were thoroughly mixed and separated into four different soil blends; 100% farm soil, 90% farm soil to 10% dredged sediment, 80% farm soil to 20% dredged sediment, and 100% dredged sediment and placed into 32 mesocosms. Soybeans were planted in half of the mesocosms. Daily watering and five random seasonal storm events were conducted during the growing season using synthetic rainwater. After 123 days, the soybean plants were harvested, and soil cores were collected for analysis. Physico-chemical analyses were conducted on the soil, plant biomass, and percolated stormwater. Results showed that dredged sediment amendment improved the quality of the farm soil by providing additional soil organic matter, increasing the cation exchange capacity and decreased P concentration in the legacy P farm soil. Nutrient loss (phosphorous and nitrogen) in the percolated solutions showed no significant changes when compared to the percolated solutions in the 100% farm soil treatment, indicating no significant contribution to the export of nutrients into waterways. Our study showed that adding dredged sediment to farm soil improved the farm soil health and showed no negative environmental impacts with respect to additional nutrient loss.

Two controlled-environment greenhouse experiments evaluated (1) plant growth and morphology of basil (Omicum basilicum L.) grown in three different hydroponic and soilless substrate systems and (2) seedling tray cell-count and transplant date into hydroponic culture effects on basil growth and yield at harvest. For the first experiment, four basil cultivars (‘Genovese’, ‘Mrs. Burns Lemon’, ‘Sweet Thai’, and ‘Cinnamon’) were grown in deep flow technique (DFT) hydroponics, nutrient film technique (NFT) hydroponics, and a novel shallow aggregate ebb-and-flood (SAEF) soilless substrate system and were harvested after 21 d. Plant yield and morphological characteristics measured at harvest included shoot fresh mass, shoot dry mass, leaf SPAD chlorophyll content, total leaf area per plant, plant height, node number, and internode length. For the second experiment, seedlings of ‘Genovese’ basil were germinated in a soilless peat-based substrate and grown in trays with cell-counts of 32, 50, 72, 105, and 162 and corresponding root volumes of (in cm3) of 98.1, 50.2, 38.5, 19.6, and 16.3, respectively. Basil seedlings for each tray type were transplanted in NFT hydroponic systems at 14 d, 21 d, and 28 d after sowing seed. Plants were harvested from NFT systems 35 d after sowing seed, and collected data at harvest included shoot fresh mass, shoot dry mass, plant height, and substrate pH and electrical conductivity (EC). Plant growth and morphology of basil cultivars differed between hydroponic and soilless culture systems, and harvested yields were overall greater for basil produced in DFT hydroponics compared to NFT hydroponics and SAEF soilless substrate systems. Basil seedlings grown in low cell-count trays and transplanted at earlier dates into NFT systems had greater yields compared to basil grown in high cell-count trays and transplanted at later dates. The combination of growing seedlings in trays with low cell-counts and early transplant into hydroponics likely increased yield by reducing potential for root restriction, increasing nutrient and water availability per plant, and increasing individual plant spacing for greater accumulation of photosynthetic light.

The Paris Agreement brings the nations of the world together to work towards limiting climate change. It is now ratified and working. Each party will submit Nationally Determined Contributions (NDCs), their country’s plans to contribute to the Paris Agreement. These NDCs discuss mitigation and adaptation and related themes. Mitigation covers a range of activities to reduce greenhouse gas emissions, such as energy efficiency and renewable energy. Adaptation includes efforts that help people adjust to climate change, such as flood control and disease management. About 90% of the world’s countries are participating in the Paris Agreement with at least one NDC as of January 2019. Additionally, the Paris Agreement requires each nation to improve upon their NDC every 5 years. How the NDCs contribute to the Paris Agreement should be better understood. What themes and trends are evident in the NDCs? I hypothesized there is increasing interest in mitigation. Additionally, further consideration of adaptation will show potential mitigation co-benefits. For the first part of this project, the NDCs were read and themes were identified by counting the number of times key words, such as mitigation and adaptation, appeared. Themes related to mitigation and adaptation included technology and land use. Additional themes, such as renewable energy, were added to the research as it became apparent that specific policies or activities are commonly discussed in the NDCs. Themes are countries’ common discussion points on climate change. Statistics were used to correlate the occurrences of themes with each other. Trends were identified by comparing the themes in the NDCs with the results of previous research on the 2015 documents. Themes were considered from the perspective of the frequency of emissions reporting, quantitative emissions targets, and progress towards meeting the goals of the Paris Agreement. Research questions and hypothesis sought to increase understanding of the NDC communication common among parties with the most ambition in mitigation. Research questions and hypothesis also sought to increase understanding of factors that might influence other countries to make more progress in mitigation. The second part of the research examined possible paths towards limiting climate change. With the results of analysis of trends and themes in mind, scenarios were developed in C-ROADS software to show possible paths to reaching the goal of the Paris Agreement to limit global temperature rise to less than 2oC. This limit in global temperature is needed to avoid the worst effects of climate change. An additional scenario was developed to address the more ambitious goal of limiting global temperature rise to less than 1.5 oC. Finally, in its third part, this project analyzed the format of the NDCs. Their lack of a consistent format poses a challenge to clear communication (Pauw et al., 2018). Currently, the NDCs do not include consistent numerical formats for emissions changes and the NDCs do not all address the same topics regarding their contributions. Based on commonalities in the contents and structure of the submitted NDCs, and their relationship to emissions reporting, a recommended format was proposed for use in future NDCs.

Electricity for supplemental lighting is a major cost of year-round crop production, so increasing efficacy of lighting is of primary concern to growers. Market opportunities may support projects with high energy use intensity, which again highlights the need for energy efficient technologies. In greenhouse production, where electric light is supplemented against a broad-spectrum background, only supplemental wavelengths with the highest photosynthetic efficiency justify the cost of electric lighting, and plant growth is largely correlated to the overall quantity of light received. Any reduction in the quantity of supplemental light, while maintaining minimum instantaneous and integrated lighting targets, will coincide with reduced electricity costs for growers. Modulating the intensity of supplemental light can be accomplished at high temporal resolution using computational control algorithms with intensity modulated LED fixtures. The current research compares the accuracy of two lighting control strategies, intensity modulation and binary off/on. Intensity modulation varies supplemental light intensity, balancing supplemental against ambient light to meet an instantaneous light intensity threshold, while binary control switches lights on at full power. Each strategy is combined with the Lighting & Shade System Implementation (LASSI) control algorithm, developed at Cornell University (Albright et al., 2000) which was originally developed for binary control of High Intensity Discharge lights. Binary control is expected to accurately provide a target DLI, with some overshoot on cloudy days that become sunny. Modulation control is expected to precisely meet a minimum threshold DLI while minimizing overshoot of supplemental lighting. Networked microcontrollers were set up to control LumiGrow 650e LED fixtures which were deployed in a greenhouse for 34 days during winter to compare binary vs. intensity modulation control. Overall, this project lays the groundwork for incorporation of additional software into dynamic greenhouse lighting systems.

The strawberry (Fragaria × ananassa) industry in the United States is dominated by open-field production, and California accounts for the majority of the crop. Demand for a year-round supply of high-quality strawberries is increasing in the U.S., and the current supply chain involves long transportation distances between the field and consumer which can reduce quality. Soilless substrate-based greenhouse production systems can extend the season and range of strawberry production by growing in a controlled environment. Greenhouses require high capital input, and fruit yield and quality (taste) need to be maximized so that greenhouse strawberry production operations are sustainable. Microclimate conditions in the greenhouse need to be further optimized to increase grower profit, and in this study, I evaluated how soilless substrate systems and aerial environmental conditions affected the yield and fruit quality of greenhouse strawberry. Specifically, the effects of four different substrate systems (two commercial and two laboratory standard) on `Albion’ plant vigor, fruit yield, and fruit quality were tested. The four substrate systems represented various combinations of physical components, containers, and microbial additives (arbuscular mycorrhizal fungi (AMF) and plant growth promoting rhizobacteria (BP)). The two commercial systems (Com1 and Com2) had 26-31% greater cumulative fruit yield per plant than our standard laboratory system. Per plant yield in the standard laboratory system with AMF (StMix-M) was not significantly different than any other system. These findings suggest that physical, chemical, and biological properties must be integrated to maximize soilless strawberry yield. Fruit quality differences between the different substrate systems were minimal. However, fruit quality was noticeable higher in Ohio than `Albion’ fruit grown in previous production experiments conducted in Tucson, Arizona. As the production systems and management were similar, differences in the greenhouse environment were hypothesized to cause the changes in quality. Total soluble solids (TSS) and titratable acidity (TA) were not significantly different between the two locations; however, Ohio TSS:TA ratio was significantly higher giving evidence for the perceived increase in fruit quality. Regression analyses were applied between Arizona TSS, TA, and TSS:TA ratio values and six environmental variables (24-hour average temperature (°C), average day temperature (°C), average night temperature (°C), maximum PPFD (µmol m-2 s-1), DLI (mol m-2 d-1), and 24-hour average VPD (kPa)). Significant positive correlations between TA and average 24-hour temperature, nighttime temperature, and daytime temperature during the fruit development period (30 days prior to harvest) (FDP) were found. Ohio FDP nighttime temperature was significantly lower than in Arizona. Therefore, we believe lower nighttime temperatures in Ohio reduced fruit TA which drove the significant increase in TSS:TA ratio. If 24-hour average temperature is maintained in an optimal range (i.e., 18 °C), nighttime temperature reduction could prove to be a reliable method to increase strawberry fruit quality.

The recent popularity of edible microgreens (young seedlings of vegetable and herbs harvested shortly after emergence of the first true leaf) has resulted in increased interest of greenhouse growers to cultivate them for local markets. Their cultivation in hoop-houses, greenhouses and indoor production vertical farms (plant factories), permit growers control over growth parameters. This in turn allows growers to influence crop yield, morphology, days to harvest (DTH) and secondary metabolites, which hold perceived health benefits with consumers. Recommendations for their germination and growth parameters vary widely by seed supplier leaving growers to determine their own ideal cultural practices best suited for their operation. The use of horticultural lighting systems to hasten growth and promote the development of aromatic compounds in microgreens has also received little attention in the published literature. Therefore, it was the objective of this study to quantify the effects of four common cultural practices, four daily light integrals (DLI) and four carbon dioxide (CO2) concentrations on the growth, morphology, DTH and secondary metabolite production of three microgreen species: arugula (Eruca sativa L.), mizuna (Brassica rapa L. var. japonica) and mustard [Brassica. juncea (L.) Czern. ‘Garnet Giant’]. We began by evaluating four seed densities (1.1, 1.65, 2.2, 2.75 and 3.3 seeds•cm-2); five fertilizer concentrations (0, 50, 100, 150 or 200 mg N•L-1); four substrate depths (1.8, 3.3, 4.3 and 5.8 cm); and four air temperatures (14, 16, 20 and 22 °C) on fresh weight (FW), fresh weight per plant (FWPP), dry weight (DW), plant height and DTH. FW and FWPP were influenced in equal but opposite quadratic fashions as seed density increased from 1.1 to 3.3 seeds•cm-2 where total FW increased while FWPP decreased. FW increased in a quadratic fashion as both fertilizer concentration and substrate depth increased from 0 to 200 mg N•L-1 and 1.8 to 5.8 cm. DTH decreased linearly as air temperatures increased from 14 to 22 °C. After parameters were established for optimal cultural practices, we sought to quantify the effects of four DLI and four CO2 levels on the growth, morphology and secondary metabolite content of microgreens. Four levels of DLI (3, 6, 9 and 12 mol•m-2•d-1) by four levels of CO2 (400, 600, 800 and 1000 ppm) were evaluated under a full factorial design. FW increased linearly for mizuna and mustard as DLI and CO2 increased from 3 to 12 mol•m-2•d-1 and 400 to 1000 ppm. Arugula FW increased in a quadratic fashion as DLI increased from 3 to 12 mol•m-2•d-1 and linearly as CO2 increased from 400 to 1000 ppm. Dry weight increased linearly for all species as DLI and CO2 increased from 3 to 12 mol•m-2•d-1 and 400 to 1000 ppm. For mizuna and mustard, DTH decreased in a quadratic fashion while arugula DTH decreased linearly as DLI increased from 3 to 12 mol•m-2•d-1 with no observed influence from CO2. Total phenolics and total flavonoids increased linearly as DLI increased from 3 to 12 mol•m-2•d-1 where the effect of DLI on phenolic content was dependent on the CO2 level. The results of these studies can help growers determine optimal cultural practices to maximize yields, minimize production time and achieve a target crop size based on individual market demand. In addition, results can help growers conclude what combination of DLI and CO2 can achieve maximum yields at the lowest lighting energy input. Growers can then determine the importance of achieving maximum phenolic and flavonoid compounds and adjust light and CO2 as needed.

Specialty leafy greens are excellent sources of antioxidants, vitamins, and minerals. Many of these metabolites are influenced by microclimate environmental conditions and genotype. The objective of this thesis was to measure the impacts of abiotic factors on plant growth and development along with nutritional content of specialty leafy greens in controlled environments. Chapter one looks at changes in biomass and nutritional content of different microgreen cultivars grown in a greenhouse over four growing seasons. Chapter two looks at the influence of light-emitting diode (LED) treatments on the growth and nutritional content of hydroponically grown kale. The morphology and nutritional content of hydroponically grown kale plants were significantly impacted by LED treatment. LED treatments with higher proportion of blue light had significantly shorter plants and greater fresh mass (FM) as compared to all other LED treatments. Environmental and genetic factors influenced the growth and development, as well as impacted the nutritional content of the different microgreen cultivars. Brassica microgreens had the highest FM and shortest production times throughout all seasons, as compared to the herb and lettuce microgreens. Whereas, the herb microgreens had the highest concentrations of shoot tissue carotenoids and minerals, as compared to brassica and lettuce microgreens. Results from this thesis provides valuable production data for producers who grow specialty leafy greens in controlled environments. Nutritional data among microgreen species may contribute to consumer knowledge for healthy eating choices.

Sustainability practices are leading to the development and use of alternative products in the floriculture and wastewater industries, such as the use of biodegradable containers instead of plastic containers. The objective of this research was to evaluate the efficacy of using digested biosolids from a regional wastewater treatment plant as an ingredient in creating a biodegradable transplant biocontainer. The biosolids were tested for metals limits as specified by the U.S. EPA Part 503 Rule, and met the requirements for Class B. Multiple mixes of biosolids, fibers, starch, polymer, and natural glue were developed to provide overall pot stability and structural strength. Engineering tests, such as tensile strength, pH, and saturated paste tests, were conducted on the different mixes to determine the optimum strength that could be produced. The top-performing biosolids mixes were used to make 10.2 cm (four-inch) pots that were compared in various ways to the market leaders, Peat Pots and standard plastic pots. A two-part mold was created on a 3D printer, which would allow for positive pressure to be used in forming the BioPots. Mixes were transferred to the lower half of the mold, the upper part was then plunged and fastened into the lower half, and then the mold with its mix was placed in an oven to dry. Laboratory germination bioassays were performed to test for the presence of phytotoxic compounds. Construction of BioPots for the lab-scale studies was tedious. Different methods (e.g., negative pressure systems) need to be investigated for use in producing the BioPots commercially. Most of the BioPots survived the resiliency study. Leachate quality from the biocontainers was no worse than from the plastic containers. Some discoloration was observed on the biocontainers, but it was not due to algal/fungal growth. Growth of soybeans, marigolds, and romaine in the biocontainers was significantly better (e.g., increased height, leaf sizes, and weight) than in the plastic containers.

Best management practices (BMPs) are used in the nursery and greenhouse industry to increase production efficiency, and also serve to help meet clean water limitations on contaminants entering waters such as the Chesapeake Bay Watershed. Research is lacking on which BMPs are most widely used or most efficacious for Virginia nursery and greenhouse growers. Objectives of this work were to determine BMP use, barriers to adoption, and scientific efficacy. We conducted a survey of Virginia growers to find the 1) most widely used BMPs, 2) reasons behind BMP use, and 3) any barriers to BMP adoption. Sixty growers (17%) responded to the survey. The most widely used BMPs included irrigation scheduling, integrated pest management, optimized irrigation efficiency, plant need based watering, grouping plants by water needs, on-site water capture and collection, and use of controlled-release fertilizers (CRFs). Cost was a barrier to BMP adoption, and environmental concern was a commonly reported reason for BMP use. We documented the science supporting selected water-related BMPs (grass buffer strips, CRFs, and irrigation optimization BMPs). Providing the science supporting BMP use gives growers confidence in implementing BMPs to limit water contamination, and prevent waste.

Soil pollution has become a problem of global concern due to industrialization and other human activities that have resulted in the release of toxic materials in to the environment. The use of lead bullets in shooting ranges releases this toxic metal which presents a risk of harm to the environment at large. Different herbaceous species and 25-30 cm soil core samples from around field plants were collected from the Grand Valley Ranch, a historic gun range in NE Ohio. The total metal content in the plants and soil were examined using acid digestion and ICP-AES. The core samples showed variation in concentrations of lead and it was noted that the top 15 cm of soil was more polluted than the bottom 15 cm thus indicating the superficial spread of lead due to water leaching horizontally. The roots of aster species (a native of the site) were able to accumulate 2106 mg/kg Pb and its shoots 112.6 mg/kg Pb. Soil from this site was collected and dried to use in a pilot study on phytoremediation by three native wetland plant species: Elymus virginicus, Panicum virgatum L. and Juncus effuses and three known hyperaccumulators of lead: Helianthus annuus, Brassica nigra and Festuca arundinacea. The plants were grown for one month in a green house and up to 6,000 mg/kg of lead in the form of lead nitrate was introduced into the collected lead contaminated soil progressively. After one week of last introduction of the lead, the plants were harvested and analyzed for lead content. Plants from the greenhouse showed similar results in accumulation with the shoots accumulating less Pb than the roots. Roots of tall fescue, common rush and dwarf sunflower accumulated 10,660, 12,229 and 42,446 mg/kg Pb respectively; shoots accumulated 6,418, 4,059 and 9,693 mg/kg Pb respectively. The highest removal rate was seen with common rush with 9.5±0.9 mg of Pb removed per g dry weight shoot and tall fescue with 15.1±0.9 mg of Pb per g dry weight shoot. The translocation factor for all samples was less than 1 suggesting that most of the lead was not moved into the shoot biomass. The bioconcentration factor (BCF) is a ratio of plant concentrations to soil concentrations. Tall fescue, common rush and dwarf sunflower all had BCF greater than 1 indicating high amount of Pb was accumulated in the biomass as compared to the soil. It was concluded that tall fescue, common rush and sunflower could serve as good accumulators/hyperaccumulators of lead for this site.

Solar, wind, and other renewable energy technologies have the potential to mitigate climate change, secure America’s energy independence, and create millions of green jobs. In the absence of a price on carbon emissions, however, these long-term benefits will not be realized without near-term policy support for renewables. This Article assesses the efficiency of federal tax incentives for renewables and proposes policy reform to more cost-effectively promote renewable energy through capital markets and crowdfunding.Federal support for renewable energy projects today comes primarily in the form of tax incentives such as accelerated depreciation and, critically, tax credits. Empirical evidence reveals that only a fraction of the subsidy value of tax credits may actually go to fund new renewable power projects. Why are tax credits for renewables so inefficient? And where do the remaining tax dollars go?Qualitative analysis suggests that the answer to both questions hinges on the mismatch between the profitability requirements of tax credits and the revenue profile of renewable energy projects. The value of tax credits lies in their capacity to reduce tax liability and lower tax bills. Most renewable power projects, however, require ten years or more to recover their up-front capital expenditures before they begin to generate taxable profits and, hence, tax liability to reduce. Bringing in investors with tax liability from other sources to monetize a project’s tax credits provides only partial relief. Such tax equity investment drives up a project’s financing charges and transaction costs, limits investment liquidity, and restricts growth in the renewable energy marketplace.Federal policymakers should give renewable energy access to master limited partnerships (MLPs) and real estate investment trusts (REITs) – two tax-privileged investment structures with a proven track record of promoting oil, gas, and other conventional energy. Merging the tax benefits of a partnership with the fundraising advantages of a corporation, MLPs and REITs could significantly reduce the cost of capital for renewable energy projects, broaden their investor appeal, and move renewables closer to subsidy independence. Most importantly, MLPs and REITs have the potential to deliver these and more benefits to renewable energy at considerably lower cost to taxpayers than the current regime of tax credits.

Phytophthora foliage blight of garden phlox (Phlox paniculata ) - caused by Phytophthora nicotianae - is a devastating disease that has been seen consistently in nursery production facilities in South Carolina. However, this disease has not been characterized previously. This project was composed of three separate studies, each of which followed one of the three major components of the disease triangle (i.e., the synchronous occurrence of a susceptible host and a virulent pathogen within a conducive environment) to investigate the pathogenicity of P. nicotianae on P. paniculata . In one study, the efficacies of three inoculation methodologies to cause Phytophthora foliage blight and reproduce symptoms similar to those seen in the nursery on P. paniculata plants were evaluated. It was concluded that propagules of P. nicotianae must be present on foliage of garden phlox plants in warm, humid conditions for longer than 24 h for disease to occur consistently. In another study, variation in susceptibility among cultivars of P. paniculata was evaluated with two methodologies: a detached-leaf assay and a whole-plant assay. Both methods were effective in determining differences in susceptibility of cultivars of garden phlox to infection by P. nicotianae . It was also shown that wounding resulted in significantly greater susceptibility to infection. The final study in this project confirmed that isolates of P. nicotianae recovered from P. paniculata differ in virulence on cultivars of P. paniculata .

Rapid changes in global and local climate and weather, noticeable over our lifetimes, have spurred heated public and political debate over the cause of these climatic changes, whether or not we can reverse, stop or slow down this process, and how to create adequate models that can predict Earth's changing climate. To create the most accurate models of future climate, many researchers look to past greenhouse intervals for insight; intervals of time identified by high modeled atmospheric CO2, a lack of glacial deposits, and geologic evidence of globally high sea-levels--all of which suggest little to no glacial ice and a relatively monotonous climate. However, recent stratigraphic and geochemical evidence from the Cretaceous 'supergreenhouse' interval document compelling evidence to support dynamic greenhouse climates. The goals of the studies hereafter described are to document and describe orbital-scale (104-105 yr) climate fluctuations recorded by δ18O as a proxy for glacio-eustasy and sea surface temperature and µNd as a proxy for continental weathering and wet/warm or dry/cool climate during two global greenhouse intervals: the Late Silurian and Late Devonian. The first study (Chapter 1) explores whether glacio-eustasy was the driver for orbital-scale shallowing-upward cycles developed in Late Silurian and early Late Devonian tropical and subtropical greenhouse climates. Two intra-cycle δ18O conodont apatite trends were observed: asymmetric trends demonstrating progressive δ18O increases coincident with facies shallowing, or symmetric trends demonstrating initially decreasing, then increasing δ18O values. These isotopic trends and intra-cycle magnitudes support the hypothesis that these cycles developed in response to glacio-eustasy during glacial stages, implying that Late Silurian and Late Devonian greenhouse climates were more dynamic than traditionally assumed. Relationships between orbital-scale continental weathering flux and glacial-interglacial marine cycles was first assessed comparing intra-cycle µNd and δ18O values from Middle Pennsylvanian icehouse cycles (Chapter 2). Observed conodont δ18O trends support previous interpretations that sampled cycles were generated by glacio-eustasy (30-50 m magnitudes) combined with

Anthropogenic levels of atmospheric greenhouse gases, particularly carbon dioxide (CO2) have increased rapidly over the last several decades and coincide with rising temperatures globally. One possible solution is to capture CO2 before it is released into the atmosphere by large point sources, such as fossil fuel power plants. Once captured, the CO2 can be condensed and transported to a storage facility. Of the available options for storage of condensed CO2, geologic sequestration in deep saline aquifers is considered the most viable option. Porosity measurements were obtained for nearly 100 core samples of the Knox and Stones River groups from the middle Tennessee area as part of a larger project for the Tennessee Division of Geology, characterizing the potential for geologic CO2 sequestration in Tennessee. Certain formations within these groups were found to exhibit higher porosity (higher storage potential) than others. Measured porosity values were quite low, ranging from 0.21 – 10.67 % with a median value of 1.21 %. These data can be used to aid in the decision-making process concerning possible geologic targets for geologic CO2 sequestration in Tennessee. A sensitivity analysis was also performed using a numerical model for geologic carbon sequestration (STOMP). Intrinsic permeability, porosity, pore compressibility, the van Genuchten residual liquid saturation, α and m parameters, and the Brooks and Corey residual liquid and gas saturations were varied independently and their influence on CO2 storage was determined. Changes in costs based on the parameter variations were calculated to evaluate the relative importance of the various parameters. The most influential parameters were intrinsic permeability, the van Genuchten m parameter, and the Brooks and Corey residual gas saturation. These results highlight the need for accurate measurement of intrinsic permeability and capillary pressure-saturation parameters in addition to more commonly measured properties like porosity.

This policy proposal makes the case for opening Master Limited Partnerships (MLPs) and Real Estate Investment Trusts (REITs) — both well-established investment structures — to renewable energy investment. MLPs and, more recently, REITs have a proven track record for promoting oil, gas, and other traditional energy sources. When extended to renewable energy projects these tools will help promote growth, move renewables closer to subsidy independence, and vastly broaden the base of investors in America’s energy economy.

This thesis is an investigation of the role of architecture in reclaiming deteriorating urban constructs, consequently restoring the placedness of a given community - in this case, East Nashville. Through careful consideration of the built environment, architecture as well as landscape architecture can transform our existence on the land and sustain a harmonious economy through the cultivation of food grown within the neighborhood. How we structure ourselves on the landscape via architecture speaks to our perception of the material world given to us.

Concerns about climate change and the increasing cost of fossil fuels have led to interest in the development of renewable biofuel pathways for reducing greenhouse gas (GHG) emissions. The use of corn residue as a potential source of biomass feedstock for cellulosic ethanol production has been favored as cost effective. Previous research has shown that crop residue removal can cause a loss of soil organic carbon (SOC), which potentially is a source of GHG emissions in the form of CO2. Using a life cycle assessment (LCA) approach, this study investigated the impact of corn residue removal on total GHG emissions for several biochemical conversion technologies at two different removal rates (50% & 90%). An inventory of total emissions from energy use in crop production and residue harvest was used with micrometeorological measurements and biomass processing data to determine the total life cycle GHG emissions for cellulosic ethanol. Due to hail damage of the crop in 2010, a modeling approach was used to estimate CO2 fluxes for both removal levels based on 9 years of previous eddy covariance flux data for continuous corn. Model prediction on average was within 7% of both the measured change in SOC and the measured CO2 flux from soil using the eddy covariance tower. The average GHG intensity based on five years of change in SOC with the combination of field measurements and the different conversion technologies was 53 g CO2 MJ-1 (45% reduction compared to gasoline) for 50% removal, and 57 g CO2 MJ-1 (40% reduction compared to gasoline) for 90% removal. Emissions of CO2 associated with change in SOC as a result of residue removal were demonstrated to be a large and important contribution to the overall GHG emission intensity of cellulosic ethanol. Compared to gasoline, the assessment results indicate that none of the conversion technologies would meet the 60% GHG emission reduction required for cellulosic ethanol from corn residue, unless soil carbon is better managed. Advisor: Adam J. Liska

Vegetation and climate both play integral roles in water availability, particularly for arid to semi-arid regions. Changes in these variables can lead to extreme shortages in water for regions that rely on water for crop irrigation (i.e., the Great Plains). The objective of this study is to evaluate the impacts of vegetation on water availability in the Republican River basin in central Nebraska. Decreases in streamflow have been observed in the river basin for many years and, as a result, an invasive riparian plant species (Phragmites australis) is being removed in an effort to reduce evapotranspiration and reclaim surface water. Meteorological variables and energy balance data have been collected at a field site during the 2009 and 2010 growing seasons. Vegetation was sprayed with herbicide in July 2009, killing all P. australis in the wetland. Significant decreases in evapotranspiration were observed during the 2010 growing season due to the limited amount of transpiring vegetation in the wetland. Greenhouse growth experiments were also conducted with both invasive and native varieties of P. australis to determine basic plant physiological parameters. Nitrogen fertilizer was applied to half of the plants in each subset. Gas exchange (e.g., photosynthesis, stomatal conductance, and transpiration rates), and the efficiency of the water and nitrogen use, were assessed under variable light, temperature and CO2 concentrations. As well as providing specific vegetation parameters for modeling purposes, this study was interested in evaluating the differences in physiology and growth characteristics between the two varieties of P. australis present in Nebraska. Lastly, the plant physiological parameters were incorporated into Agro-IBIS, a dynamic vegetation model, and this model was evaluated using observed energy balance data from the wetland field site from 2009. Experiments were also performed for 2010 to assess the ability of the model to capture the response to vegetation removal. Adviser: John Lenters

A commercial African violet (Saintpaulia ionantha) grower experiences yield loss due to a leaf spot disease known as Corynespora casssiicola. Spotted leaves make the plants unmarketable. Outbreaks of the disease are costly and difficult to prevent. Greenhouse monitoring systems currently available on the commercial market do not have sufficient spatial or temporal resolution to be able to correlate the environmental conditions of the greenhouse with disease outbreaks. A new system was designed specifically to monitor for disease favorable conditions. The system developed for this project consists of several sensor stations and a coordinator station. The coordinator station is connected to a PC and periodically collects data from all sensor stations through a wireless communications network. Data enters the PC in an easy to analyze comma-delimited format. Each sensor station is entirely self-contained and battery operated to minimize inconvenience to producers. The stations are small enough to fit into the footprint of a four inch potted plant. Each station measures temperature, relative humidity, and light levels and can last for at least two months on a single battery charge. When tested in a commercial greenhouse, sensor stations were able to detect significant spatial differences in environmental conditions. By placing these stations at regular, close intervals throughout the greenhouse producers can gain a more accurate picture of current environmental conditions in their crop than they have been able to obtain in the past. If these readings are combined with disease outbreak information, producers will be able to determine if there is a correlation between certain environmental conditions and disease outbreaks.

We conducted ninety- four s urveys among small growers of greenhouse ornamental in three Northeastern states to examine factors that influence IPM adoption. We construct four a lternative dependent variables describing t he e xtent of IPM adoption, and employ Standard Logit, Ordered Logit and Tobit models to indentify factors affecting IPM adopt ion. We find that IPM adopters are more likely to operate large farms, use more full time workers, and have diversified operations to include vegetables. Greenhouses that s uffered serious disease problems are less likely to adopt IPM practices; t he positio n of head growers in the greenhouse operations is also influential in IPM adoption. Our findings reveal that unavailability o f biological control agents is a great hindrance for growers to adopt IPM. Our analysis also highlights substantial difference between t he self- reported IPM measure and t he three objective IPM measures.

Here, I evaluate biospheric evolution during the Ordovician using high-resolution inorganic carbon and sulfur (carbonate-associated sulfate and pyrite) isotope profiles for Early Ordovician to early Late Ordovician strata from geographically distant sections in Western Newfoundland and the Argentine Precordillera. Additionally, I present new, high-resolution U-Pb ages for volcanic ash beds within strata of the Argentine Precordillera. Carbon isotope data record subdued variation that is typical of Early- to Middle Ordovician strata worldwide. By contrast, sulfur-isotopic compositions of carbonate-associated sulfate reveal a complex signal of short-term, rhythmic variation superimposed over a longer-term signal. This short-term, rhythmic variation occurs in all sections and appears to be unrelated to lithology or depositional environment, suggesting preservation of an oceanographic signal. I interpret this signal to reflect a combination of a marine sulfate reservoir that was likely much smaller than the modern, the persistence of a substantial deep-ocean hydrogen sulfide reservoir, and the episodic oxidation of a portion of the deep-ocean euxinic reservoir. Persistent euxinia likely resulted from decreased solubility of oxygen in warmer water and/or sluggish oceanic circulation during greenhouse conditions that reduced vertical ventilation. A dramatic change in the behavior of carbonate-associated sulfate and pyrite in the Middle Ordovician is interpreted to reflect a major oceanographic event that records the initial transition from Ordovician greenhouse to icehouse states. I suggest that the initiation of downwelling of increasingly cool, oxygen-rich surface water resulted in widespread oxidation of much of the deep ocean hydrogen sulfide reservoir and concomitant limitation of marine pyrite formation. It is unknown, however, why sea surface temperatures declined through the Early to Middle Ordovician. Explosive volcanism does not appear to be a primary climate driver, based on the timing of Argentinian K-bentonite formations relative to marine records of sea surface temperature, carbon and strontium isotopic composition. Rather, long-term positive feedback between organic carbon burial rates and productivity may have increased carbon dioxide drawdown, ultimately driving a gradual decrease in sea surface temperatures in the Early to Middle Ordovician.

The primary goal of this paper was to increase profitability in Nebraska greenhouses by using biomass fuels for heating instead of propane. Several different fuels were tested, including whole shelled corn, dry distiller’s grains pelletized, wood pellets and blends between each biomass. The main fuel focus was on whole shelled corn. Bomb calorimetry tests were performed on biomass fuels and their respective ashes. Several furnace and heat exchanger efficiency tests were performed, with cost effectiveness analysis for each fuel type. Emissions data was also collected for each fuel on carbon monoxide, carbon dioxide, nitrous oxides, sulfuric oxides, and particulate matter. The project used a biomass furnace donated to a greenhouse at Firth, Nebraska and an existing propane furnace. Although the biomass furnace generally had a lower efficiency than the 81 percent advertised for the propane furnace, the biomass fuels were more cost effective than propane. The biomass efficiencies typically ranged between 50 and 80 percent. Over a four year period (2008-2011) the cost savings of biomass fuels ranged between 30 and 60 percent and totaled a little over $15,000. Overall, biomass furnaces show great potential to be utilized in Nebraska greenhouses. Advisor: George E. Meyer

The effect of elevated CO2 on growth, development, nutrient concentration and insect performance was evaluated in petunias (Petunia×hybrida Vilm.) and zinnias (Zinnia elegans L.) grown at sub-optimal air temperature. Elevated (700 µmol·mol-1) and ambient (390 µmol·mol-1) CO2 concentrations were used to grow plants in chambers and greenhouse environments using a recommended “optimal” (21 °C) and a sub-optimal (3 °C lower than optimal) air temperature. Controlled Release Fertilizer (CRF) was used at low and high rates to test the effect of CO2 and temperature on plant nutrition. Whiteflies (Bemisia tabaci Gen.) were infested on plants to evaluate oviposition and nymph development. The growth chamber study revealed that petunias and zinnias grown at elevated CO2 were shorter than plants at low CO2 levels. High fertility increased plant dry weight for both crops. While the number of flowers in zinnias was increased with high fertility, flower longevity and time to flower were not affected. On the other hand, higher number of flowers, longer flower longevity and shorter time to flower was observed in petunias grown at high CO2 and sub-optimal temperature. N, K, Ca, Mg, S and C were not affected by either CO2 or temperature treatments, whereas P had higher concentrations in petunias grown at low CO2 with optimal temperature. However, in zinnias, Mg was the only nutrient affected by CO2 levels. In the greenhouse study, higher plant dry weights and heights were measured with high fertility in petunias but not in zinnias. The number of flowers increased for both crops while the longevity and time to flower decreased for petunias and remained unchanged for zinnias with the high fertility treatment. Nutrient concentrations in petunias were not affected by the CO2/temperature combination whereas in zinnias an increase in C/N ratio was observed. While early mortality of whiteflies infested on petunias caused insufficient data to evaluate insect performance, zinnia’s growth was negatively affected by the presence of insects. Whiteflies’ oviposition rate was reduced and nymph developmental time increased by sub-optimal temperature at both chamber and greenhouse studies. It has been demonstrated with this study that the combination of CO2 enrichment and a slight reduction in air temperature may not compromise plant quality and scheduling. Furthermore, positive results in terms of pest management and fertilization can be achieved.

Shamrock Plant (Oxalis regnellii) is an ornamental plant grown primarily for St. Patrick's Day. Interveinal chlorosis is a production problem and has been hypothesized to be caused by micronutrient deficiencies, either iron (Fe) or manganese (Mn) or virus. Several experiments were conducted testing these hypotheses. A virus screen was conducted and positive identification was found and plants were rouged. Oxalis plants were grown hydroponically on five NO3--N:NH4+-N ratio treatments. Increasing proportions of NO3--N increased total leaf, root, flower, and bottom shoot biomasses. Other hydroponic studies were conducted removing Fe and Mn from nutrient solutions to characterize the respective deficiencies. Iron deficiency, characteristic interveinal chlorosis on newly developed leaves was observed as early as three weeks after removing Fe. Plants grown without Mn did not exhibit interveinal chlorosis, but were slightly less green than control plants grown in complete nutrient solutions. Iron deficiency was also induced in a greenhouse media, using dolomitic lime. Again, typical interveinal chlorosis and reduced plant growth was observed after two weeks. Tissue analysis confirmed the chlorosis was due to reduced Fe as opposed to limited N or Mn concentrations. Our data suggest Fe influences interveinal chlorosis more than Mn. Micronutrient chelate foliar and media applications were assessed as corrective measures for foliar chlorosis. Media drenches of Fe-EDDHA were effective in regreening Fe deficient oxalis in 5 days. Foliar chelate applications were less effective. Organic acids, such as oxalic acid often assist plants in nutrient acquisition through root exudation. Oxalic acid levels of recently matured leaves increase in Fe deficient O. regnellii plants. Cultural practices such as temperature, irrigation, and fertilizer selection also influence plant growth and incidence of leaf chlorosis. Our research found that cooler temperatures (13˚ C) did not increase chlorosis and temperatures of at least 21˚ C produced more aesthetically pleasing and floriferous plants. Overhead irrigation, compared with subirrigation produced higher quality and larger O. regnellii. Plant growth and development is best when fertilized with N rates between 100 mg N[MIDDLE DOT] L-1 and 350 mg N[MIDDLE DOT] L-1.

Abstract summary not available

Rice (Oryza sativa L.) life cycle and yield depend on the partitioning of assimilated carbon to ripening caryopses. Structural and functional aspects of this important process were investigated. First, spatiotemporal dynamics of ripening were assessed. Panicle fresh weight accumulation was maximum after three weeks and had a maximum rate after twelve days. Panicle architecture and ripening asynchrony were reduced to the form of an annotated panicle array. This format permitted a quantitative, computational approach to panicle consensus generation, data analysis and graphical display. Next, the separability of caryopsis tissues was assessed. The caryopsis coat was mechanically isolated from most of the embryonic tissues and facially separated into outer and inner coats from within the tube cell layer. Pectolyase Y-23 compromised adhesion between the maternal nucellus and embryonic aleurone and between endosperm cells. Viable protoplasts were prepared from approximately 10% of the isolated endosperm cells. Low protoplast yield was correlated with low viability of the isolated cells. Third, the mechanism of sucrose uptake by the aleurone was studied. The sucrose concentration-dependence of uptake rate had a nonsaturable component and a relatively small saturable component. Finally, electrophysiology of the caryopsis coat was assessed. Membrane potentials of the aleurone and nucellus were approximately -60 mV and -80 mV, respectively, and invariable over a range of bath conditions. Sucrose negligibly depolarized the aleurone membrane potential. Thus, it was not possible to confirm that the saturable sucrose influx was mediated by a cotransport system. Overall, the work has increased the experimental accessibility of ripening panicles and caryopses for research on the control of carbon partitioning.

Data were collected from bedding and potted plant growers serving the wholesale and retail markets to determine business characteristics, average annual gross sales, average fixed and variable costs, costs per square foot per week ($/ft²/wk) or costs per square foot per year ($/ft²/yr) and utilization of space. Business size, including greenhouse area, outdoor pads, fields and supplemental buildings, ranged from 85,337 ft² to 222,336 ft². Greenhouses were the primary production area for bedding and potted plant growers, while cut flower growers primarily used field production. Bedding and potted plant growers averaged sales of $896,519 compared to sales of $45,423 for cut flower growers. Wholesale markets had higher sales than retail markets for bedding and potted plant businesses and cut flower businesses. Labor was the greatest expense for all market segments. Correlation analysis indicated a positive association between advertising costs and sales in the wholesale markets. Positive associations in the retail markets were found between employee compensation and sales and conference/travel expense and sales. Financial data collected from bedding and potted plant growers serving the wholesale and retail markets was used to determine space utilization and fixed costs per square foot per week ($/ft²/wk). Calculation of this cost included adjustments for space and time utilization. Wholesale bedding and potted plant growers were determined to have fixed costs of $0.236/ft²/wk and retail bedding and potted plant growers had a cost of $0.334/ft²/wk for greenhouse production area. Financial data collected from wholesale and retail cut flower growers were used to determine space utilization and costs per square foot per year ($/ft²/yr). The wholesale cut flower businesses were determined to have a fixed cost of $1.220/ft²/yr, while the retail cut flower businesses yielded a cost of $0.787/ft²/yr for field production. Businesses can compare their own costs to these industry averages. Costs per square foot per week and costs per square foot per year are valuable tools for business management and efficiency analysis. Monthly space utilization differentiated by production area was determined for each market segment. Bedding and potted plant growers primarily used greenhouses for production with some production on outdoor pads. Peak greenhouse usage for wholesale bedding and potted plant growers occurred in April (95.5%), and retail bedding and potted plant growers' greenhouses were most utilized in April and May (87.5%). Cut flower growers primarily used field production though some also utilized greenhouse space. Field production peaked in June (85%) for wholesale cut flower growers and in July (88%) for retail cut flower growers.

After years of intense debate, global climate change has finally been acknowledged as aserious threat to global biological, political and economic systems. There is overwhelming evidencethat the atmospheric warming observed over the course of the past 50 years, as well as theincreasing incidence of extreme weather events and floods, is being caused by the acceleration ofthe rate in which greenhouse gases (GHGs) produced by the burning of fossil fuels are beingreleased into the atmosphere. The extreme weather and weather-related eventsassociated with climate change, such as landslides and flooding, totaled roughly $40 billion in the1990s. It is not surprising, then, that the governments of many developed anddeveloping nations, as well as intergovernmental bodies like the United Nations and the WorldBank, have adopted a variety of measures to reduce GHG emissions and mitigate the potentialimpacts of climatic change. The government of Slovakia sold credits for 200,000 metric tons ofcarbon dioxide equivalents to a Japanese trading house at an undisclosed price on December 6,2002, making history by signing the first deal to be officially credited within the internationalKyoto Protocol, a global agreement to reduce the GHG emissions of participating countries sevenpercent relative to their 1990 levels by 2010. Nor is it surprising thatenvironmental interest groups and active citizens in the United States and elsewhere are pressingtheir elected leaders to pass stricter regulations on the emission of GHGs.What is somewhat baffling, though, is the number of privately owned companies that havetaken it upon themselves to voluntarily reduce GHG emissions as a way to address climate changein recent years. Dozens of companies are voluntarily participating in the design andimplementation of GHG emission reductions programs. For example, the International EmissionsTrading Association (IETA) lists 47 international members including Gaz de France, British Petroleum, Shell International Limited, Norsk Hydro and Unocal. Private for-profit groups likethe Chicago Climate Exchange (CCX), a pilot emissions reduction credit (ERC) trading program,and C02e.com, Cantor Fitzgerald's online emission trading market, are forming partnerships withprivate companies to devise strategies for reducing emissions in the quickest and most cost-effectivemanner. Government programs like the Greenhouse Gas Emissions Reduction TradingPilot (GERT) in Canada and other programs in France and the United Kingdom are formingsimilar partnerships. Nonprofit environmental groups like Environmental Defense and the WorldWildlife Fund have their own, similar pilot projects. Most of these voluntary programs are centeredaround emissions trading, a policy tool commonly utilized for its cost effectiveness and ability toyield abatement results.