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Articles 1 - 18 of 18
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Farms-Sponsored Researcher Searches For More Plant Evidence Of Voyages From India To America
Farms-Sponsored Researcher Searches For More Plant Evidence Of Voyages From India To America
Insights: The Newsletter of the Neal A. Maxwell Institute for Religious Scholarship
Assisted by a grant from the Foundation, Carl L. Johannessen, Emeritus Professor of Geography at the University of Oregon, is now in India with an assistant searching for sculptured images of sunflowers and other American crop plants. Their earlier studies documented that images of maize from the New World had been carved on temple sculptures in India dating to medieval times, centuries before the Spaniards and Portuguese could have carried the plant to Asia after A.O. 1500, as scholars commonly suppose (Johannessen and Parker, "Maize Ears Sculpted in 12th and 13th Century A.O. India as Indicators of Pre-Columbian Diffusion," Economic …
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Insights: The Newsletter of the Neal A. Maxwell Institute for Religious Scholarship
On March 27 Carl Johannessen, emeritus professor of Geography from the University of Oregon, spoke about evidences found in the ancient Old World of crops normally considered indigenous to the New World, particularly maize. His discussion, entitled "Diffusion of Cultural Traits across the Oceans in Pre-Columbian Times," included a slide presentation showing ancient architecture that depicts what he argues is maize. If his evidence is confirmed by additional research, it will help establish the existence of contacts between the Old and New Worlds before Columbus, thus helping to establish the plausibility of the Book of Mormon account.
Parametric Models Of Maize Stalk Morphology, Michael Alan Ottesen
Parametric Models Of Maize Stalk Morphology, Michael Alan Ottesen
Theses and Dissertations
As the most produced grain crop world-wide, 5% of corn is lost due to stalk lodging (above-ground structural failure of the stalk near the roots). Current modeling methods lack the ability to manipulate the stalk architecture. In contrast, parameterized models enable advanced analyses such as sensitivity and optimization studies. This thesis advances previous work on a parameterized cross-sectional model of maize stalk morphology and investigates the validity of a parameterized three-dimensional model. The parameterized cross-sectional model is based upon previous work that approximated the cross-section of maize stalks using an ellipse plus principal components. Validation of the cross-sectional model was …
Electrical Capacitance Measurements To Assess European Corn Borer Infestation In Maize, Mavrik D. Thomas
Electrical Capacitance Measurements To Assess European Corn Borer Infestation In Maize, Mavrik D. Thomas
Theses and Dissertations
The European Corn Borer (ECB), Ostrinia nubilalis, is an agricultural pest which bores small holes in the rind of maize stalks and then proceeds to consume the pith. Because most of the damage to the stalk is internal, it is difficult to quantify the damage to an individual stalk without time-consuming, manual examination. This work explored the hypothesis that internal damage could be detected and quantified using non-destructive, electromagnetic measurements. Laboratory experiments and numerical simulation studies predicted changes in capacitance of stalks due to hollow core ECB damage. A guarded probe device to measure electrical impedance from 500 Hz to …
Measuring And Modeling Evapotranspiration, Yield And Water Productivity Of Maize Under Different Agricultural Management Practices, Kobusinge A. Nyabwisho
Measuring And Modeling Evapotranspiration, Yield And Water Productivity Of Maize Under Different Agricultural Management Practices, Kobusinge A. Nyabwisho
International Congress on Environmental Modelling and Software
Due to increasing global population and pressure on non-renewable soil and freshwater resources, feeding the future is a challenge that needs to be tackled through a lens of water productivity. More than 80% of the world agriculture is rainfed, and this leads to low crop yields in semi-arid regions (including the study area) that experience low and unreliable rainfall. To improve crop yield per drop of rainwater, we need management practices that reduce water loss from the field through evaporation so as to increase plant available water and yield. Three management practices were tested for their ability to reduce soil …
Development Of A Parameterized Model Of Transverse Maize (Zea Maysl.) Stalk Morphology, Ryan A. Larson
Development Of A Parameterized Model Of Transverse Maize (Zea Maysl.) Stalk Morphology, Ryan A. Larson
Theses and Dissertations
Stalk lodging, or failure of the stalk structure, presents a serious problem in the production of maize (Zea mays L.). Lodged stalks negatively impact crop yields by inhibiting further grain growth and often prevent the harvest of the grain. Addressing this problem requires the development of new maize hybrids that exhibit enhanced lodging resistance, which in turn requires an understanding of the parameters that influence lodging resistance. Current methods make use of specimen-speciï¬c geometry and material properties, but these methods have limited ability to examine geometric effects and can require excessive time. A parameterized model of the maize stalk has …
Comparison Of The Glue And Dream Methods For Estimating Variety Parameters For A Maize Crop Modelcomparison Of The Glue And Dream Methods For Estimating Cultivar Parameters For A Maize Crop Model, Meiling Sheng, Junzhi Liu, A-Xing Zhu, Liming Zhu
Comparison Of The Glue And Dream Methods For Estimating Variety Parameters For A Maize Crop Modelcomparison Of The Glue And Dream Methods For Estimating Cultivar Parameters For A Maize Crop Model, Meiling Sheng, Junzhi Liu, A-Xing Zhu, Liming Zhu
International Congress on Environmental Modelling and Software
Process-based crop models are popular scientific tools to study the impacts of environment, variety and management decisions on crop growth. Some cultivar parameters in crop models cannot be measured directly and need to be estimated. In this research, two Bayesian methods, namely the generalized likelihood uncertainty estimation (GLUE) and Differential Evolution Adaptive Metropolis (DREAM) algorithm, were used to estimate the parameters of the maize module of the Agricultural Productions Systems sIMulator (APSIM-Maize) for the first time. Six cultivar parameters of APSIM-Maize were estimated using GLUE and DREAM, respectively. Both the GLUE and DREAM methods were able to give accurate simulations …
Diversity In Tiller Suppression Of Domesticated Cereals: Morphologicalvariance Observed In Maize, Sorghum, And Setaria, Muriel Tahiameiani Longstaff
Diversity In Tiller Suppression Of Domesticated Cereals: Morphologicalvariance Observed In Maize, Sorghum, And Setaria, Muriel Tahiameiani Longstaff
Theses and Dissertations
Tillers are vegetative branches found in grasses, which develop in early stages of plant life. Located at the base of the central stalk, tillers have agronomical importance by increasing seed production with fewer tillers, or providing alternative forms of biofuel with more tillers. As grains have typically decreased tiller number while undergoing domestication, we explored wild and domesticated strains of varying grains by doing a morphological analysis on tiller development. This thesis shows how the decrease of tillers through in domestication cereals shows diversity not only across maize, Sorghum, and Setaria, but also between lines of maize and Setaria species. …
Assimilation Of Sar And Optical Data Into An Agro-Meteorological Model For Monitoring Yield Of Corn, Maël Ameline, Rémy Fieuzal, Julie Betbeber, Jean-Franҫois Berthoumieu, Frédéric Baup
Assimilation Of Sar And Optical Data Into An Agro-Meteorological Model For Monitoring Yield Of Corn, Maël Ameline, Rémy Fieuzal, Julie Betbeber, Jean-Franҫois Berthoumieu, Frédéric Baup
International Congress on Environmental Modelling and Software
This study aims to assess the contribution of SAR and optical satellite images to estimate corn biophysical parameters and crop yield at field scale. Satellite data are assimilated into a simple agro-meteorological model named SAFY-WB (Simple Algorithm For Yield estimates combined with a Water Balance model), in order to simulate leaf area index, dry mass and yield. The method has been assessed thanks to data collected over two study areas (both located in the South-West of France), during two experimental campaigns: MCM’10 and MCM’15 (Multispectral Crop Monitoring), respectively performed in 2010 and 2015. SAR backscattering coefficients were acquired in the …
Evidence Of Ancient Maya Agriculture In The Bajos Surrounding Tikal, Guatemala, Adam Calvin Parker
Evidence Of Ancient Maya Agriculture In The Bajos Surrounding Tikal, Guatemala, Adam Calvin Parker
Theses and Dissertations
Current Central American agricultural practices are environmentally and economically unsustainable, yet the ancient Maya who lived in the same region thrived for thousands of years. Archaeologists have attempted to understand the factors enabling the prolonged success and ultimate collapse of the Maya societies. Some have proposed that the karst seasonal wetlands, called bajos, that border many Maya sites in the region were an influential factor in the Maya's ability to flourish. For the past decade, researchers have used carbon isotope analyses to identify areas of ancient maize agriculture at Maya archaeological sites. In this study, we collected soil samples from …
Improving Phosphorus Use Efficiency Through Organically Bonded Phosphorus, Micheal W. Hill
Improving Phosphorus Use Efficiency Through Organically Bonded Phosphorus, Micheal W. Hill
Theses and Dissertations
Current maximum efficiency of phosphorus (P) fertilizers that is utilized by plants in the same year of application ranges from near zero to thirty percent. Despite low utilization of P in crop production, yields are often limited by P deficiencies. Innovative technology is requisite to achieve greater efficiency as fertilizer demands are increasing, while phosphorus mineral resources are rapidly being depleted. A growing environmental concern for nutrient pollution of surface waters also carries significant weight. A novel new product, Carbond® P, is promising technology to increase P use efficiency. Research is needed to understand its capabilities and the functioning mechanisms …
Effectiveness Of Phosphorus Fertilizers In Hydroponics And Glasshouse Settings With Moderate And High Organic Matter Soils, Jeffrey Sean Christian Summerhays
Effectiveness Of Phosphorus Fertilizers In Hydroponics And Glasshouse Settings With Moderate And High Organic Matter Soils, Jeffrey Sean Christian Summerhays
Theses and Dissertations
Phosphorus (P) is poorly soluble in most soils and, thus, has poor plant uptake efficiency. AVAIL® and Carbond P (CBP) are new fertilizer products shown to increase P use efficiency (PUE) and increase crop yields when grown in P limiting soils. Carbond P has specifically been seen to increases P uptake and crop yields in soils low in P, although effectiveness in regards to soil organic matter is unknown. The objectives of these studies were to determine if the mode of action for these products is related to physiological response, to determine if Carbond P is toxic to plant roots …
Environmental Implications Of Polymer Coated Urea, Joshua James Lemonte
Environmental Implications Of Polymer Coated Urea, Joshua James Lemonte
Theses and Dissertations
Nitrogen is an essential plant nutrient in the biosphere. Although N is necessary and beneficial for life, it is also a common pollutant in the atmosphere and hydrosphere as it may be lost to the atmosphere as ammonia (NH3) or nitrous oxide (N2O) gases or to groundwater as nitrate (NO3-) following fertilization. Polymer coated urea (PCU) is one type of N fertilizer which uses temperature-controlled diffusion to control N release to better match plant demand and mitigate environmental losses of N. The objectives of this project were to simultaneously compare the effects of PCU on gaseous (as N2O and NH3) …
Stable Carbon Isotope Evidence Of Ancient Maya Agriculture At Tikal, Guatemala, Richard Lee Burnett
Stable Carbon Isotope Evidence Of Ancient Maya Agriculture At Tikal, Guatemala, Richard Lee Burnett
Theses and Dissertations
Stable carbon isotope analyses of the humin fraction of the soil organic matter were conducted on more than 160 soil profiles from Tikal, Guatemala. The profiles were collected from near areas associated with the earthworks of Tikal; an ancient ditch and parapet construction hypothesized to have formed ancient boundaries of the polity. In addition to the isotope analyses, the physical and chemical characteristics of the horizons were determined. Maize, a C4 plant, formed an integral part of the ancient Maya diet and is the only known C4 plant cultivated by the Maya. Prior to and subsequent to the ancient Maya …
The Prolamins Of Pearl Millet, Christian B. Ricks
The Prolamins Of Pearl Millet, Christian B. Ricks
Theses and Dissertations
Although work on the prolamins of pearl millet (Pennisetum glaucum) has revealed partial amino acid sequences for several alcohol-soluble storage proteins (Marcellino et al. 2002) the genes encoding them have not yet been isolated. We constructed a cDNA library from developing P. glaucum seed tissue and screened it using maize zein gene probes to isolate several α-prolamin-like gene sequences. The proteins encoded by these genes generally fall into two size classes: 20.6kD and 27.1kD, which we call the 21kD and 27kD pennisetins. Both proteins are similar in composition and sequence to α-prolamins from maize, sorghum and Coix. Protein bodies that …
Mano And Metate Manufacturing Techniques Of The Maya: An Ethnoarchaeological Approach To Understanding Standardization And Measurements, Michael T. Searcy
Mano And Metate Manufacturing Techniques Of The Maya: An Ethnoarchaeological Approach To Understanding Standardization And Measurements, Michael T. Searcy
Faculty Publications
Prehistorically, maize was the bulk of the Mayan diet, which made grinding stones an indispensable tool. Basalt quarries located in Highland Guatemala are still exploited by metateros who produce manos and metates today. This paper reports the recent research among metateros of two quarries in Guatemala and how they can be use to build new analogies that aid in the interpretation of prehistoric production economies of metates. It specifically investigates how systems of measurement are linked to standardization.
Predicting Maize Yield, Nutrient Concentration And Uptake In P And K Fertilized Soils: Pressurized Hot Water And Other Alternatives To Mehlich I Extraction In Guatemala Soils, Heather Mae Hunsaker
Predicting Maize Yield, Nutrient Concentration And Uptake In P And K Fertilized Soils: Pressurized Hot Water And Other Alternatives To Mehlich I Extraction In Guatemala Soils, Heather Mae Hunsaker
Theses and Dissertations
The inaccessibility and cost of soil testing reduce effectiveness of fertilizer use on small-scale subsistence farms, and inadequate funding promotes adoption of soil tests in developing countries with minimal validation. For example, Mehlich-I extraction of phosphorus (P) currently used extensively in Guatemala may not be suitable for its broad range of soils. At least four alternatives are available but are relatively untested [Bray 1, Mehlich III, Olsen and pressurized hot water (PHW)]. Pressurized hot water is relatively simple and inexpensive, but is not yet tested against other extraction methods under variable P or potassium (K) fertilization levels. To determine whether …
Soil Stable Carbon Isoptope Analysis Of Landscape Features At Aguateca, Guatemala, David R. Wright
Soil Stable Carbon Isoptope Analysis Of Landscape Features At Aguateca, Guatemala, David R. Wright
Theses and Dissertations
The ancient Maya of the Classic period (1700-1050 B.P.) relied on maize agriculture to support their populations. The agricultural systems they employed to produce that maize varied in form and degree of intensity, with more productive forms of agriculture needed in the Late Classic period (1350-1050 B.P.) to sustain the peaking population. It is likely that the ancient systems of production agriculture contributed to environmental degradation that in turn contributed to the pressures that culminated in the collapse of the civilization. In this study, stable carbon isotope ratios contained in the soil organic matter were used to further investigate ancient …