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Full-Text Articles in Animal Sciences
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 …
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 …