Browsing by Author "Johnson, Jeff"
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Item An economic analysis of cattle weight gain response to nitrogen fertilization and irrigation on WW-B. Dahl bluestem(2005-12) Dudensing, Jeffrey D'Wayne; Johnson, Jeff; Johnson, Phillip N.; Lansford, Vernon D.; Villalobos, CarlosThe objective of this research was to estimate total stocker steer gains ha-1 at various levels of nitrogen fertilization and irrigation application on WW-B. Dahl Old World bluestem. In order to do this, forage mass and quality responses to nitrogen (N) and irrigation (I) had to be determined. The data for this study were obtained from two independent studies conducted from 2001 to 2003 at Texas Tech University. Stata statistical software was used to obtain coefficients for the effects of accumulated growing degree days (AGDD), N, I, precipitation, and maturity on forage mass and quality. Quality assessments were based on acid detergent fiber (ADF), neutral detergent fiber (NDF), and crude protein (CP). Panel data with fixed effects was the most appropriate statistical model. Statistical tests confirmed that the model was corrected specified. From the forage mass and quality values, the National Research Council’s Nutrient Requirements of Beef Cattle 2002 equations were used to estimate total stocker steer gain ha-1. In estimating total stocker steer gains, a monthly utilization of 70% of forage mass was assumed. Estimated average daily gains were validated with previous research. The results agreed with the findings of Mitchell et al. that GDD could be used to estimate forage mass and quality. However, N, I, precipitation and maturity can be incorporated into Mitchell’s model to increase the understanding of forage mass and quality. By using these regressions and incorporating them into the NRC equations, the response to variable rates of N and I was evident in stocker steer gains. Three initial steer weights (181 kg, 227 kg, and 272 kg) were used to capture the effect on gains. Results indicated that individual steer gains were higher with low irrigation and high nitrogen fertilization levels. Total cattle gains were maximized with high irrigation and high nitrogen levels.Item An evaluation of lint yield, fiber quality, and an economic analysis of upland cotton cultivars(2011-05) Stroud, Matthew K.; Thompson, Thomas L.; Bednarz, Craig W.; Johnson, Jeff; Hequet, Eric F.ABSTRACT An Evaluation of Lint Yield, Fiber Quality, and an Economic Analysis of Upland Cotton Cultivars. By MATTHEW K. STROUD, B.S., Texas Tech University (Under the Direction of Thomas Thompson and Craig Bednarz) Water management is a major issue in agriculture production in semi-arid regions such as the High Plains of West Texas. With weather patterns changing from year to year, it is crucial to properly manage irrigation. We observed response functions of multiple irrigation levels on cotton lint yield, fiber quality, and profit. Studies were conducted at Texas Tech University Research farms in Lubbock and New Deal, TX, in 2009 and 2010. Subsurface drip irrigation (SDI) zones were used to evaluate cotton performance. Irrigation treatments ranged from 0 to 0.60 cm per day in 0.05 cm increments. Rainfall between years and locations affected the relationship between irrigation and lint yield. In 2009, at the Quaker (Lubbock) farm, maximum yield occurred at 0.52 cm day -1, before the highest watering level of 0.60 cm day-1, due to below average rainfall. Rainfall quantity and timing impacted fiber quality parameters including micronaire, length, strength and length uniformity. Yield and profit maximums were reached before the highest watering levels for the Quaker 2009 location. In 2010 data was affected by rainfall events at both locations of over 15 cm during squaring. Immediately before harvest, lint yield was reduced to due to a hail storm. It is crucial to observe many years and types of environments to make solid conclusions or recommendations to producers. 2009 had a below average rainfall, while 2010 had an above average rainfall amount. It is imperative that producers properly manage irrigation based on their given environment.Item Analysis of percipitation and saturated thickness of the Texas Ogallala Aquifer(2010-08) Warren, Ada R.; Mulligan, Kevin; Lee, Jeffrey A.; Johnson, JeffThe Ogallala Aquifer is an important source of groundwater for agricultural and municipal supplies on the Texas High Plains. It is widely recognized that water levels in the aquifer are declining at an average rate of about one foot per year. Declining aquifer water levels are a result of water extraction occurring faster than aquifer recharge. Although the water levels of the aquifer are declining, the rate of decline fluctuates year-to-year and it seems reasonable to assume that variations in annual or seasonal precipitation contribute to the variability in the rate of decline. The precipitation rates affect the amount of water extracted by producers for irrigating crops. To address this problem, the objective of this thesis was to determine if precipitation has an effect on the rate of water extraction from the Ogallala Aquifer. This study compares the annual change in saturated thickness with precipitation data for the study area to determine the relationship between aquifer drawdown and precipitation. Well data for the Ogallala Aquifer were acquired for 1990 to 2008 for 10 counties on the Southern High Plains. The well data were used to calculate saturated thickness and rate of decline for each year. The saturated thickness was compared with annual and seasonal precipitation totals for each year. The results from this study found that annual precipitation amount has a statistically significant effect on the rate of decline of saturated thickness of the Ogallala Aquifer in Texas. Furthermore, seasonal precipitation will have a greater effect on the rate of decline of saturated thickness than annual precipitation.Item Cotton Gin Trash Availability on the Texas High Plains for Bioenergy(2010-05-03T15:55:50Z) Farmer, Michael; Johnson, Jeff; Wilde, CurtisAs the demand for bioenergy increases, agricultural products are being studied to determine their feasibility for use in producing bioenergy. One of the most important factors in the feasibility of the use of any product for bioenergy production is that crop’s availability. Gin trash has been shown to have potential as a boiler or combustion unit fuel, useful in electricity production; additionally, it has also shown to have potential use in ethanol production. Therefore, the objective of this study is to determine the availability of cotton gin trash in 30 counties located on the Texas High Plains (THP). In these 30 counties, 994,736 short tons of cotton gin trash were produced annually. Ten counties were responsible for 55.67% of the cotton gin trash production in this 30 county area.Item Cotton lint yield, fiber quality, and water-use efficiency as influenced by cultivar and irrigation level(2013-05) Cave, Justin; Keeling, Wayne; Dotray, Peter A.; Ritchie, Glen L.; Johnson, JeffCotton is produced in the Texas High Plains under a wide range of water levels, ranging from dryland (rainfed) to full irrigation, with irrigation levels that depend on well capacities. With declining pumping capacities, it is important to maximize water-use efficiency (WUE) through crop management and cultivar selection. The objectives of this research were to 1) evaluate the lint yield and fiber quality of current commercial and experimental cotton cultivars, 2) determine the WUE of these cultivars in different irrigation settings 3) identify the returns above cost for each cultivar within irrigation treatments, and 4) determine which cultivar is best for producers with varying levels of irrigation water and risk preference on the Texas High Plains. Field studies were conducted in 2011 and 2012 to evaluate new cultivars under varying irrigation inputs at Lamesa and Lubbock, TX. The experimental design at both locations was a split plot design with irrigation as the main effect and cultivar as the split effect. Eight cultivars [DP 0912 B2RF, DP 1032 B2RF, DP 1044 B2RF, DP 1212 B2RF, DP 1219 B2RF, 11R110B2R2, 11R112B2R2 (DP 1321 B2RF), and 11R159B2R2 (DP 1359 B2RF)] and four irrigation levels, replicated three times were evaluated in 2011 at Lubbock and Lamesa. Target irrigation levels were 0, 30, 60, and 90% ET replacement. In 2012, twelve cultivars with four replications were evaluated including the eight from 2011. The four additional experimental cultivars included: 11R124B2R2 (DP 1311 B2RF), 11R136B2R2, 11R154B2R2, and 12R242B2R2. Due to the excessive temperatures and drought conditions experienced in 2011, a reduction in yield and fiber quality was seen at both locations. At both locations in both years, increased yields were produced at increased irrigation levels; however, no cultivar by irrigation level interaction was observed. In 2012 at Lamesa, WUE declined as irrigation increased while no differences in WUE between irrigation levels were observed in Lubbock. Over all four trials, no cultivar by irrigation interaction for WUE was observed. Staple length tended to increase as irrigation increased, while the relationship of other fiber quality parameters was less pronounced. Net returns varied among cultivars, and influenced which cultivars were preferred by producers with different risk preferences. In both years at Lubbock, DP 1321 B2RF was the most preferred cultivar for risk averse producers, while DP 1219 B2RF and DP 1359 B2RF were among the most preferred cultivars for risk averse producers in three out of the four trials. In both 2012 locations, 11R136B2R2 had fiber length greater than or equal to all other cultivars.Item Cotton profitability as influenced by cultivar, irrigation level, nitrogen level, and harvesting system(2012-12) Keeling, William; Johnson, Jeff; Wang, Chenggang; Boman, Randal K.Cotton (Gossypium hirsutum L.) is an important crop in the United States that is grown across the country stretching from California in the west to Virginia in the east. Increasing production costs, volatile market prices, and shifting mill demand from domestic to overseas markets has resulted in more uncertainty in the cotton market, raising the importance of cotton quality with respect to overall profitability. The Texas High Plains (THP) region has historically grown lower yielding and grade cotton that has utilized stripper harvesting methods. Advances in genetics, crop management, and irrigation efficiency have improved the yield and quality of cotton grown in the region. The objectives of this research were to increase profitability through the most profitable combination of cultivar selection, irrigation and nitrogen level, and harvesting method at the farm level. Specific objectives were to determine if it is more profitable to adopt a picker harvesting system over the currently used stripper harvesting system, whether an increased irrigation and nitrogen level had an impact on overall profitability, and if choosing a picker type cultivar over a stripper type cultivar would increase profitability. Yield, average cotton price, and gross margin were estimated for cultivar selection, irrigation level, nitrogen level, and harvesting system. The results from this study show that producers can increase their gross margin with higher irrigation levels and proper cultivar selection, but do not benefit from increased nitrogen levels. Under the conditions of this study, producers in the THP will not necessarily benefit from switching to a picker harvesting system over the traditional stripper harvesting system. This study highlights the importance for producers to effectively manage inputs and their corresponding levels for overall profitability.Item Cotton yield response to water and nitrogen interaction under various inrrigation practices(2012-12) Sapkota, Praveen; Maas, Stephan J.; Johnson, Jeff; Rajan, NithyaThe Texas High Plains region is characterized as arid and has variable growing condition. Due to the weather unpredictability, economic productivity of cotton is below the US national average level. Excessive water extraction and limited aquifer recharge is the main cause for the decline in the Ogallala Aquifer, which is the only major source of water in THP. Farmers in this region are facing problems due to limited irrigation and high nitrogen prices, which result in reduced cotton production. Irrigation and nitrogen are the two most important factors for maximizing cotton production. In this research, I attempt to make an efficient and effective evaluation of utilization of these factors. During the study, various water and nitrogen treatment levels were simulated with the Cotton2k crop simulation model for center pivot irrigated and dryland cotton to see the response of cotton yield. Thirty years (1975-2004) of cropping season weather data from four high plain counties, Crosbyton, Muleshoe, Plainview, and Seminole, were used for the simulation. Factorial combinations of various treatments were made. For dryland 0, 1.8, 3.7, 5.5, 7.3, 9.2, 11.0, and 12.8 kg/ha (0, 10, 20, 30, 40, 50, 60, and 70 lbs/acre) of different levels of nitrogen were used and for center pivot irrigation, total water of 4.6, 9.2, 13.8, 18.4, 23, 27.6, 32.2, 36.8 inches was combined with 0, 4.6, 9.2, 13.8, 18.4, 22.9, 27.5, and 32.1 kg/ha (0, 25, 50, 75, 100, 125, 150, and 175 lbs/acre) of nitrogen level. The yield results were analyzed and the results showed that, for rainfed condition, best yield of 882 kg/ha were found with the application of 60lbs/acre. For center pivot irrigated field, when 175 lbs/acre of nitrogen was applied, maximum yield occurred with dose of 83 cm of water. Further study should focus on economic analysis.Item Economic evaluation of an integrated cropping system with cotton(2005-12) Martin, Rebekka; Lansford, Vernon D.; Segarra, Eduardo; Johnson, Jeff; Allen, Vivien G.; Harman, WyatteCotton is the primary crop in the Southern High Plains of Texas. Increased irrigation of cotton has reduced the Ogallala aquifer water supplies. The reduced levels of the aquifer have led to an increased cost of producing cotton as depth of pumping increases over time, causing farmers to look for alternative crop production systems that reduce water demands from the Ogallala aquifer. The objectives of this research were to investigate the profitability and risk of an integrated system with crops and livestock compared to monoculture cotton production and to evaluate the environmental effects of the two systems. The economic performance of each system (monoculture cotton vs. integrated crop-livestock system) was evaluated using biophysical crop growth model to simulate yields for 20 years. A sensitivity analysis for 9 price levels (high, average, and low at 10%, 30%, and 50% price variability) was used for cotton, cattle, and grass seed production to evaluate the sensitivity of the two systems to price changes. Stochastic dominance with respect to a function (SDRF) was used to compare the risk efficiency of the integrated and monoculture systems. Crop production and environmental effects were modeled using WinEPIC Version 3.0.Item Economic evaluation of winegrape contracts, risk sharing, and implications for the future of the industry(2011-05) Pate, Daniel K.; Johnson, Jeff; Hellman, Edward W.; Wang, ChenggangSales contracts for wine grapes are fundamental to both the winery and the grower. While several surveys have been completed to determine the extent of contract use, specific contract provisions, and aspects of implementation, no studies using the lens of principal-agency theory have been published regarding winegrape contracts. This study explores current contracting methods by evaluating winegrape pricing methods, production risk transfer, and incentive/disincentive stipulations in agricultural contracts between vineyards and wineries. The results show that contracts offering a fixed payment will result in lower quality fruit on average compared to quality incentive compensation. Furthermore, in the event any particular grape quality parameter is an informative signal and worth measuring, it is worth explicitly incorporating into the contract by means of a bonus/penalty for that particular attribute or by profit sharing linked to the retail wine price. In markets where contracting per-ton pervades, the focus on quantity predominates. This suggests that in the face of the grape quantity-quality tradeoff paradox, it may be possible to infer the relative end-product outcome balance in this context.Item Economic impacts of ENSO forecast information for winter wheat and stocker cattle production(Texas Tech University, 2007-12) Liu, Xiaolan; Johnson, Jeff; Mauget, Steven; Rejesus, Roderick M.Accurate forecasting of El Ninƒko events would prove very valuable to winter wheat producers in the Southern High Plains of Texas. Variability of rainfall is one of the greatest hazards affecting crop production and stocker cattle production in dryland regions, and typically associated with low and unstable crop yield due to unreliable rainfall. Winter wheat used as dual purpose (DP) crop for grain and grazing has been used to improve profitability in the region by producing two sources of revenue and providing management flexibility in times of inter-seasonal weather variability. Integrating accurate seasonal weather forecasts into management strategies would improve management strategy and provide opportunities to refine production plans to fit forecasted weather conditions. It has been demonstrated that the El Nin5o Southern Oscillation (ENSO) phenomenon is the main source of inter-annual climate variability in many parts of the world. This study analyzed the impacts on farm-level decision making that would result from improved forecasts based on the effects of ENSO during the winter growing season for wheat and stocker cattle producers in the South Plains region of Texas. Profit projections for this study were based on simulated yields of wheat grain and forage data for Plainview, Texas from 1915-1990. The study evaluated 75 scenarios of management strategies, including alternative planting dates, seeding densities, and fertilizer application rates. The ENSO forecasts included one observed weather condition (representing a perfect forecast method) and three alternative forecast methods which varied by the number of phases and the monthly ENSO index used. This study provides two approaches¡Xthe deterministic economic model on fixed price and the stochastic simulation economic model, in order to compare the results of the two approaches. The results obtained from stochastic dominance analysis of this study found that a dominant management strategy did exist for each weather condition (wet, dry, normal), and the level of risk aversion of the decision maker influenced the corresponding rankings of the other strategy preferences. Grazing winter wheat as dual purpose crop had a significant effect on profitability of dryland winter wheat production and negative returns were obtained from wheat grain-only production in all alternative strategies under dry weather condition. The value of information (VOI) was calculated for each of the three forecasting methods as they relate to winter wheat and stocker cattle production. Each method had a relative value of information with the five-phase June-July method (5P-JJ) having the highest value for wheat-grain producers. This study emphasizes the fact that dryland farmers could improve their profits or reduce their losses by incorporating ENSO forecasts into management decision making process when given weather expectations of the coming season from improved forecasts.Item Effects of Cotton Variety Selection and Irrigation Level on Economic Returns: Texas Southern High Plains(2010-05-03T15:56:26Z) Johnson, Phillip; Keeling, J.W; Johnson, Jeff; Wilde, CurtisAs technology increases and new varieties are released for cotton production, producers have more options when choosing inputs and input levels. Studies have been conducted at the Agricultural Complex for Advanced Research and Extension Systems (AG-CARES) research facilities at Lamesa, Texas to determine the agronomic impacts of variety selection and applied irrigation level on cotton production. This study analyzes the effects of variety selection and irrigation level and allocation of limited irrigation water for irrigated cotton producers in the Texas Southern High Plains. For this study, the authors considered three varieties with three irrigation levels. The results show that newer indeterminate picker type varieties yielded higher, had greater response to irrigation, and produced larger profit margins than traditional determinate stripper type varieties.Item Effects of irrigation termination date on cotton yield and fiber quality(2012-05) Reeves, Heath; Ritchie, Glen L.; Bednarz, Craig W.; Hequet, Eric F.; Johnson, JeffFiber immaturity decreases profits for many cotton producers on the Texas High Plains. Correct timing of the final irrigation may enhance crop maturity and conserve water. Irrigation termination shortly after physiological cutout may inhibit the production of young fruit and divert additional resources to existing fruit, promoting fiber maturity. The objective of this research was to determine if proper irrigation termination can increase crop maturity rate and improve fiber quality without affecting yield. Studies were conducted for three site-years on sub-surface drip irrigation at Halfway, New Deal, and Lubbock, Texas in 2010 and 2011. Multiple cultivars were grown under three irrigation termination methods: incremental termination at nodes above white flower (NAWF) = 5 + 2 weeks; incremental termination at NAWF = 5 + 4 weeks; and complete irrigation cut-off at NAWF = 5 + 6 weeks. Production and retention of the uppermost flowers and fruit were measured, as well as fiber quality from the harvested plots. In 2010, length was improved with earlier termination at the Halfway location. At the Quaker location, seed yield, lint, turnout, and length improved with later termination, but micronaire became less desirable. In 2011, turnout and micronaire were improved with earlier irrigation termination. When the cost of irrigation was low, the 4 week irrigation treatment was the most profitable in 2010, but as the cost of irrigation reached $10/ha-cm, the Halfway location became more profitable with the 2 week irrigation. In 2011, net income between irrigations was not statistically different.Item Essays on climate change: Economic impacts and public opinion analysis(2013-08) Tewari, Rachna; Johnson, Jeff; Hudson, Darren; Wang, Chenggang; Patterson, DennisThe past few decades have witnessed an increasing concern among researchers, political groups, governmental agencies as well as citizens across the world regarding global warming which is an inherent aspect of long term climate change. In order to understand and analyze policy considerations incorporating climate change, this dissertation explored the issue of climate change from three individual perspectives. The first essay used a climate data based economic modeling approach to predict future impacts of climate change in the Texas High Plains. The results indicated that climate change will lead to reduction in groundwater availability and irrigated production, consequently affecting the farm revenue and crop mix in the study region. The second essay evaluated the impact of climatic and socio-economic variables on agricultural land prices under different land uses in the Northern and Southern High Plains of Texas, using a Ricardian approach. The results suggested that temperature changes significantly influenced the productivity of irrigated land thereby strongly impacting the land prices, when compared to dryland and ranchland, while ranchland prices were significantly influenced by precipitation. Finally the third essay analyzed the importance of various individual and macro variables in shaping the cross-national perceptions of citizens in high carbon emitting nations regarding the seriousness of global warming, and their willingness to pay for environmental concerns.Item Essays on crop insurance yield guarantee and product choice decisions(2011-08) Adhikari, Shyam; Knight, Thomas O.; Belasco, Eric J.; Johnson, Jeff; Trindade, A. AlexandreThe U.S. Federal Crop Insurance Program has been continuously reviewed for issues relating to proper insurance guarantees and actuarially sound premium rates. Moral hazard and adverse selection were among the major identified issues considered in the past, while other issues include the yield guarantee level, rate making, and crop insurance participation. Two issues in existing crop yield insurance were identified for this dissertation research and are discussed and examined separately in chapters 3 and 4. The first issue is variability in the yield guarantee created by using a short, four to ten year yield history to establish the guarantee. Policy mechanisms that have been developed to mitigate this small sample problem are incorporated into the analysis. The second issue examined is spatial heterogeneity in crop insurance product choice decisions. A review of the literature in chapter 2 summarizes prior studies and clarifies the gap filled by the present work. Chapter 5 summarizes our findings and provides direction for future research. The first essay (chapter 3) examines the issue of sampling variability in yield guarantees applicable for the APH-based crop insurance products offered under the Federal Crop Insurance Program. Crop yield and revenue insurance products with coverage based on actual production history (APH) yields dominate the program in terms of liability insured and premiums collected. The APH yield, which plays a critical role in determining the coverage offered to producers, is based on a small sample of historical yields for the insured unit. The properties of this yield measure are critical in determining the value of the insurance to producers. An APH yield based on a small sample of historical yields has the potential to lead to over-insurance in some years and under-insurance in other years. Premiums, which are in part determined by the ratio of the APH yield to the county reference yield, are also affected by variations in APH yields. Congress has enacted two measures, yield substitution and yield floors, which are intended to limit the degree to which small samples can reduce the insurance guarantee and producer welfare. We examine the impact of the small sample problem and related policy provisions for Texas cotton, Kansas wheat, and Illinois corn. The analysis is conducted using county level yield data from the National Agricultural Statistics Service (NASS) and individual insured-unit-level yield data obtained from the Risk Management Agency (RMA) insurance database. Our findings indicate that variation in insurance guarantees due to small samples in APH yields has the potential to reduce producer welfare and that the magnitude of this effect differs substantially across crops. The yield substitution and yield floor provisions mitigate the negative impact of small samples but also bias insurance guarantees upward, leading to increased government cost of the insurance programs. The second essay (chapter 4) examines the spatial components of producer heterogeneity in crop insurance product selection among U.S. corn producers and identifies neighborhood spillover or agent marketing effects in these decisions. County-level insurance and yield data are used to demonstrate that a gradual shift from yield-based insurance to revenue-based insurance has spatial patterns. Conventional risk variables such as yield variability, price variability, prevalence of irrigation, other crops, and yield-price relationships play an important role in this shift and are consistently estimated only when spatial components are included. A spatial random effects model is used to identify the impact of spatial lag effects, which include neighborhood spillover, and potentially, agent marketing effects, on the share of corn acres insured with revenue-based versus yield-based crop insurance plans. Variables associated with risk are found to significantly influence the choice between crop revenue and yield insurance. Nonlinear parameters identify the region-specific effects on insurance decisions of factors including changes in percentage of irrigated acres, yield price correlation, and the percentage of corn acres to total acres. In addition, spatial components that might include decisions made by nearby producers or agent marketing drives are also found to influence decisions. These results may demonstrate the relative influence of trusted sources, such as nearby producers and insurance agents, on insurance decisions. Traditional risk variables are consistently estimated only by controlling for spatial heterogeneity.Item Irrigation response in cotton to optimize yield, quality and profitability in the Texas high plains(2009-05) Mathis, Garrett M.; Bednarz, Craig W.; Johnson, Jeff; Boman, Randal K.An imperative issue facing production agriculture on the South Plains is water availability. Over time, water has been drawn out of the Ogallala Aquifer at a rate that exceeds its ability to recharge. Therefore, efficient irrigation levels and seeding rates that optimize cotton quality and yield are vital to this region. A two-year study consisting of one cotton variety, three levels of irrigation and three diverse plant populations was located at two locations in Lubbock County, Texas in 2007 & 2008. Irrigation played a significant role in many yield and fiber quality measurements. The lowest irrigation treatment matured the earliest and produced low yields but had the highest micronaire values. Lint yields were highest for the high irrigation treatment at two of the three locations, but saw decreased fiber quality due to lack of maturity. Seeding rate played a small role in determining yield and fiber quality. Three different weather patterns had varying effects on the results of this study. An economic analysis determined the net return from lint with regard to variable inputs in order to provide profitability comparisons for the producer. The highest net returns from lint ranged from $1,308.34 (Quaker 2007) to $2,851.62 (Quaker 2008). We conclude that weather patterns, coupled with irrigation, heavily impact fiber yield and quality in the Texas High Plains.Item Nitrous Oxide Boiler Development for the Dream Chaser® Spacecraft Thermal Control System(44th International Conference on Environmental Systems, 2014-07-13) Metts, Jonathan G.; Miller, Stephen W.; Johnson, Jeff; Quinn, GregoryThe Dream Chaser® human spacecraft utilizes excess nitrous oxide propulsion oxidizer as an evaporant to provide heat rejection for the vehicle’s Active Thermal Control System. This capability is provided by a nitrous oxide boiler, currently in development. Performance analysis and test results indicate that a heat exchanger boiling nitrous oxide with a propylene glycol/water coolant fluid can provide the required heat rejection for Dream Chaser while preventing freezing or incomplete phase transition in the boiler unit. Integration of nitrous oxide boiler technology will result in a net system mass savings.Item Oenothera elata: Economics and best management practices for commercial production(2012-05) Bonds, Amber N.; McKenney, Cynthia B.; Wester, David B.; Henry, Gerald M.; Montague, David T.; Johnson, JeffOenothera elata Kunth, Hooker’s evening primrose, is a biennial to short-lived perennial found in a variety of habitats ranging from xeric to mesic. Currently it has limited use in landscapes. A similar species, Oenothera biennis L. or common evening primrose, is currently grown as a nutraceutical crop. The seed oil contains gamma linolenic acid (GLA), which has been used to treat ailments including eczema, arthritis, auto-immune disorders, and high cholesterol. Most primrose production is in China, because of the cooler climates which allow for increased GLA in the seed. Hooker’s evening primrose is found in warmer climates and has a similar oil profile to that of common evening primrose when grown in Lubbock, TX. This may mean there is potential for Hooker’s evening primrose production as a niche crop in this area. Best management practices must be established and cost of production must be determined before production can increase. Therefore, objectives of this research were 1) to determine spacing, irrigation, and fertility requirements for this species, 2) to evaluate several pre- and postemergence herbicides for use in O. elata production, 3) to determine most efficient harvest practices by evaluating different harvest methods and defoliants, and 4) to determine cost of production. Research was conducted at the Texas Tech University Greenhouse complex and the Texas Tech University Plant and Soil Science Research Farm in Lubbock, TX. All experiments were replicated twice throughout the 2009-2011 growing seasons. To determine irrigation, spacing, and fertility needs an experiment was set up as a split-split plot design with irrigation (33%, 66% or 100% ET) as the main plot, spacing (0.3 m, 0.6 m, or 0.9 m) as the sub-plot, and fertility (133.79 kg N ha-1, 89.19 kg N ha-1, 44.60 kg N ha-1, and 0 kg of N ha-1) as the sub-sub plot. This experiment had six blocks and every combination was represented once in each block. Data taken included: yield, visual appearance on a criterion reference scale of 1-10, number of flowers, plant growth index (PGI), and percent floral density. Pre- and postemergence herbicide trials were set up as a randomized complete block design with five replications. These experiments were conducted in the greenhouse. Data were recorded for O. elata phytotoxicity, plant biomass, and PGI. For the postemergence herbicide experiment 4 month old seedlings were placed in containers and acclimatized for 28 days before treatment with one of the following herbicides: glyphosate, glufosinate, fenoxaprop, fluazifop, sulfosulfuron + non-ionic surfactant, quinclorac + methylated seed oil, mesotrione, and quinclorac + mecoprop + dicamba + methylated seed soil. For preemergence herbicide studies applications of oxadiazon, isoxaben, oryzalin, prodiamine, dithiopyr, metolachlor, pendimethalin, and isoxaben + trifluralin were applied two days prior to the transplanting of four month old O. elata seedling. To determine harvest practices, two different experiments were set up as a randomized complete block design. Both experiments had 4 blocks and each treatment was represented once within a block. One experiment compared yield after the use of three defoliants [Paraquat, (Ethephon + Cyclanilide) + (Thidiazuron + Diuron), and Ethephon] to a non-treated control. The other compared yield of two different harvest methods (hand and Hege combine). Cost of production was determined using best management practices investigated in the previous trials. Data suggest Hooker’s evening primrose planted at 0.9 m spacings will increase appearance, flower number, PGI, and floral density. This spacing will not decrease yield. Irrigation equivalent to 66% reference evapotranspiration (ETo) increased appearance, PGI, and number of flowers in times of drought, but will not influence yield. Fenoxaprop and fluazifop may be used as postemergence herbicides without excessive phytotoxicity or reduction in growth. All preemergence treatments except trifluralin + isoxaben exhibited low phytotoxicity and will not reduce growth. Machine harvesting does not decrease yield and should reduce the cost of production. Defoliants can be used to harvest this species without a loss in yield. Paraquat and (Ethephon + Cyclanilide) + (Thidiazuron + Diuron) may be preferred over Ethephon alone. Cost of production is estimated at $1906.89 per acre. Growers will need to receive approximately $0.48 per pound in order to break even.Item Optimal economic combination of irrigation technology and cotton varieties on the High Plains of Texas(2008-05) Wilde, Curtis; Johnson, Jeff; Johnson, Phillip N.; Keeling, WayneCotton is the leading agricultural crop in the Texas High Plains. Cotton producers have experienced steady to declining cotton prices coupled with increasing input costs resulting in tightening profit margins. Many new and improved technologies including varieties and irrigations systems are being developed and used in production agriculture. Producers are adopting these new technologies; however, they need information on the proper management of these technologies to help maximize their returns and insure their continued profitability. Therefore, the objectives of this research were to determine the farm-level economic impact of the adoption of subsurface irrigation vs. center pivot irrigation, determine the farm level economic impact of the adoption of new, higher yielding and higher quality varieties, and determine the optimal combinations of applied irrigation water and variety selection for irrigated cotton farms on the Texas High Plains. Cotton yield and quality data collected from irrigation studies under different technologies and variety selection at the AG-CARES research farm at Lamesa, TX and the Helms research farm at Halfway, TX will be evaluated to meet these objectives. Gross margins and net returns above total variable and fixed irrigation costs were estimated for varieties and irrigation systems with different irrigation levels. The results obtained from this analysis showed that producers could increase gross margins by adopting new varieties. In addition, estimations showed that Sub Surface Drip Irrigation can produce higher net returns than Low Energy Precision Application center pivot systems. Estimations from two locations demonstrate the importance of managing production according to environmental factors. Top performing varieties differed between locations along with optimal irrigation levels. This analysis emphasizes the importance for cotton producers to be informed and properly manage their production.Item Optimizing Production of Castor and Winter Safflower on the Texas High Plains(2011-08) Oswalt, Joe S.; Auld, Dick L.; Johnson, Jeff; Bednarz, Craig W.; Birney, David M.; Miller, Travis D.Energy and water are the two most important commodities that keep our economy operating at optimum performance and efficiency. As world supplies for petroleum are being depleted and demand for oil is increasing, a renewed interest in establishing agronomic crops that produce an economical, reliable alternative source of oil has been established with vigor. Demand for oil is eminent, and biodiesel is an energy alternative that can be produced from vegetable oil. At the same time, water use efficiency of these crops must be advanced. To effectively grow crops for oil, water must be consumed at lower rates than conventional crops. Therefore, a crop that is water use efficient is imperative, especially if it could be grown during winter months to reduce demand on the Ogallala aquifer during peak summer months. This research resulted in production guidelines for safflower (Carthamus tinctorius L.) exhibiting winter hardiness and water use efficiency as a new winter crop for the Texas High Plains and Desert Southwest. Guidelines were also established for castor ( Ricinus communis L.), which has tremendous potential as an oilseed crop to produce biofuels, industrial oils, and has the highest oil yield potential for the short season, semi-arid production areas of the High Plains and Trans-Pecos Regions of Texas. However, castor plants can reach heights of over twelve feet (three meters) in a single growing season limiting mechanical harvest. This research also evaluated the effect of plant growth regulator applications on mature castor plant height and seed yield of castor (cv. Hale) to enhance mechanical harvest efficiency. The results of this research will allow farmers to incorporate the oilseed crops castor and winter hardy safflower into their crop rotation strategy in a manner that is profitable and easily adapted to current farming practices, saving water and contributing to greater energy independence for the U.S. vItem Palmer amaranth and ivyleaf morningglory management in enhanced glyphosate-resistant cotton(2007-05) Batla, Max A.; Dotray, Peter A.; Keeling, Wayne; Johnson, Jeff; Boman, Randal K.Cotton is a major crop on the Texas Southern High Plains. One of the main pests associated with cotton is weeds. Some common and troublesome weeds present in cotton include Palmer amaranth, devil’s-claw, and ivyleaf morningglory. Control of these weeds is crucial and information is important to area producers. Studies were conducted in 2005 and 2006 at the Texas Agricultural Experiment Station near Lubbock to 1) evaluate glyphosate timings in combination with preplant incorporated (PPI) and postemergence (POST) residual herbicides for improved Palmer amaranth and devil’s-claw control, 2) evaluate glyphosate application timings for Palmer amaranth competition in enhanced glyphosate-resistant cotton, and 3) evaluate glyphosate rates in combination with preemergence (PRE) and POST residual herbicides, and mechanical cultivation for improved ivyleaf morningglory control.