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Articles 1 - 11 of 11
Full-Text Articles in Physical Sciences and Mathematics
Addressing Soil Carbon Sequestration Response From Multispecies Dairy Forage Systems And Modeling Rangeland Beef Cow Dry Matter Intake Using Precision Enteric Emissions Measurements, Lillian J. Mcfadden
Addressing Soil Carbon Sequestration Response From Multispecies Dairy Forage Systems And Modeling Rangeland Beef Cow Dry Matter Intake Using Precision Enteric Emissions Measurements, Lillian J. Mcfadden
Electronic Theses and Dissertations
Regenerative agriculture is a pressing matter for the dairy industry to address cropland sustainability and carbon sequestration. One regenerative management practice that has been identified to help with row crop sustainability for key metrics like soil organic carbon (SOC) is complex covers. When producers use complex covers one of the main challenges is that it takes time to detect a change in SOC. However, simulation models are a tool that can be used to help determine if a regenerative practice is a strategy that gives the best results (i.e., increased SOC) while aligning with long-term production goals. Therefore, our objectives …
Modeling The Impact Of Grazing On Water Budgets, Ying Zhao, Stephan Peth, Julia Krümmelbein, Bettina Ketzer, Yingzhi Gao, Christian Bernhofer, Rainer Horn
Modeling The Impact Of Grazing On Water Budgets, Ying Zhao, Stephan Peth, Julia Krümmelbein, Bettina Ketzer, Yingzhi Gao, Christian Bernhofer, Rainer Horn
IGC Proceedings (1997-2023)
No abstract provided.
Economic Trade-Offs Of Novel Forage Use In Livestock Production Systems: Insights From Australia, Marta Monjardino, Neil D. Macleod, Dean K. Revell
Economic Trade-Offs Of Novel Forage Use In Livestock Production Systems: Insights From Australia, Marta Monjardino, Neil D. Macleod, Dean K. Revell
IGC Proceedings (1997-2023)
Globally, livestock are a major component of agricultural systems and natural resource management, as well as an important contributor to nutrition and livelihoods, but are often undervalued (Herrero et al., 2009). In Australia, livestock production systems occupy half of the available land and contribute to ~50% of gross agricultural production. The main livestock systems are beef cattle grazing at low intensity in the arid and semi-arid regions of northern and central Australia; and sheep flocks integrated in crop-livestock systems in the temperate zone of southern Australia (Bell et al., 2014). Despite increased physical productivity (changes in outputs relative …
Modeling Gross Primary Production Of Midwest Maize And Soybean Croplands With Satellite And Gridded Weather Data, Gunnar Malek-Madani
Modeling Gross Primary Production Of Midwest Maize And Soybean Croplands With Satellite And Gridded Weather Data, Gunnar Malek-Madani
Department of Geography: Dissertations, Theses, and Student Research
The gross primary production (GPP) metric is useful in determining trends in the terrestrial carbon cycle. Models that determine GPP utilizing the light use efficiency (LUE) approach in conjunction with biophysical parameters that account for local weather conditions and crop specific factors are beneficial in that they combine the accuracy of the biophysical model with the versatility of the LUE model. One such model developed using in situ data was adapted to operate with remote sensing derived leaf area index (LAI) data and gridded weather datasets. The model, known as the Light Use Efficiency GPP Model (EGM), uses a four …
A Realistic Meteorological Assessment Of Perennial Biofuel Crop Deployment: A Southern Great Plains Perspective, Melissa Wagner, Meng Wang, Gonzalo Miguez-Macho, Jesse Miller, Andy Vanloocke, Justin E. Bagley, Carl J. Bernacchi, Matei Georgescu
A Realistic Meteorological Assessment Of Perennial Biofuel Crop Deployment: A Southern Great Plains Perspective, Melissa Wagner, Meng Wang, Gonzalo Miguez-Macho, Jesse Miller, Andy Vanloocke, Justin E. Bagley, Carl J. Bernacchi, Matei Georgescu
Andy VanLoocke
Utility of perennial bioenergy crops (e.g., switchgrass and miscanthus) offers unique opportunities to transition toward a more sustainable energy pathway due to their reduced carbon footprint, averted competition with food crops, and ability to grow on abandoned and degraded farmlands. Studies that have examined biogeophysical impacts of these crops noted a positive feedback between near-surface cooling and enhanced evapotranspiration (ET), but also potential unintended consequences of soil moisture and groundwater depletion. To better understand hydrometeorological effects of perennial bioenergy crop expansion, this study conducted high-resolution (2-km grid spacing) simulations with a state-of-the-art atmospheric model (Weather Research and Forecasting system) dynamically …
The Costs Of Photorespiration To Food Production Now And In The Future, Berkley J. Walker, Andy Vanloocke, Carl J. Bernacchi, Donald R. Ort
The Costs Of Photorespiration To Food Production Now And In The Future, Berkley J. Walker, Andy Vanloocke, Carl J. Bernacchi, Donald R. Ort
Andy VanLoocke
Photorespiration is essential for C3 plants but operates at the massive expense of fixed carbon dioxide and energy. Photorespiration is initiated when the initial enzyme of photosynthesis, ribulose-1,5-bisphosphate carboxylase/ oxygenase (Rubisco), reacts with oxygen instead of carbon dioxide and produces a toxic compound that is then recycled by photorespiration. Photorespiration can be modeled at the canopy and regional scales to determine its cost under current and future atmospheres. A regional-scale model reveals that photorespiration currently decreases US soybean and wheat yields by 36% and 20%, respectively, and a 5% decrease in the losses due to photorespiration would be worth approximately …
Testing Predictions Used To Build An Agrivoltaics Installation On A Small-Scale Educational Model, Katie Kinney, Rebecca Minor, Greg Barron-Gafford
Testing Predictions Used To Build An Agrivoltaics Installation On A Small-Scale Educational Model, Katie Kinney, Rebecca Minor, Greg Barron-Gafford
STAR Program Research Presentations
Models are valuable tools for explaining and testing systems. Small-scale models can be especially useful for educational purposes. For models to be useful, they have to accurately depict the larger system that they are describing. A novel man-made system, known as an agrivoltaic structure, is being constructed at Biosphere 2 near Oracle, Arizona. The word agrivoltaic is a combination of agriculture and photovoltaics, or solar farming. My research involved creating a small-scale version of this system for educational purposes. The model of this system tested two predictions: that plants will grow better in the shade of a panel and that …
An Individual-Based Model Of Chaparral Vegetation Response To Frequent Wildfire, Timothy Lucas, Dayna Mann, Reanna Dona
An Individual-Based Model Of Chaparral Vegetation Response To Frequent Wildfire, Timothy Lucas, Dayna Mann, Reanna Dona
Seaver College Research And Scholarly Achievement Symposium
In recent years, the Santa Monica Mountains (SMM) have been plagued by frequent wildfires which threaten the native chaparral species. Nonsprouting chaparral species are completely killed by a fire, but their seeds germinate in response to fire cues. Facultative sprouters both resprout after a wildfire and release seeds that germinate post-fire. This project is based on data collected since 1986 at a biological preserve adjacent to the Malibu campus of Pepperdine University with an average fire return interval of 7.5 years. We present a spatial model that simulates the growth, seed dispersal and resprouting behavior of individual shrubs that compete …
Modeling Of Soil Sealing By Urban Sprawl In Wukro, Ethiopia Using Remote Sensing And Gis Techniques, Ahmed Harb Rabia A.H. Rabia
Modeling Of Soil Sealing By Urban Sprawl In Wukro, Ethiopia Using Remote Sensing And Gis Techniques, Ahmed Harb Rabia A.H. Rabia
Ahmed Harb Rabia A.H. Rabia
Soil sealing is the covering of the soil surface with materials like concrete and stone, as a result of new buildings, roads, parking places but also other public and private space. Soil sealing by urban sprawl continues to increase all over the world where the area of urbanized land is increasing even more rapidly than the population. The degree of sealing is associated to the land use type and the density of population. Techniques of Remote Sensing and Geographical Information System (GIS) have been used widely to measure urban sprawl and to analyze the spatial features and unique mechanism of …
Water And Energy Balance Response Of A Riparian Wetland To The Removal Of Phragmites Australis, Phillip Mykleby
Water And Energy Balance Response Of A Riparian Wetland To The Removal Of Phragmites Australis, Phillip Mykleby
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
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 …
Diurnal Variation In The Basal Emission Rate Of Isoprene, Jennifer L. Funk, Clive G. Jones, Christine J. Baker, Heather M. Fuller, Christian P. Giardina, Manuel T. Lerdau
Diurnal Variation In The Basal Emission Rate Of Isoprene, Jennifer L. Funk, Clive G. Jones, Christine J. Baker, Heather M. Fuller, Christian P. Giardina, Manuel T. Lerdau
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Isoprene is emitted from numerous plant species and profoundly influences tropospheric chemistry. Due to the short lifetime of isoprene in the atmosphere, developing an understanding of emission patterns at small time scales is essential for modeling regional atmospheric chemistry processes. Previous studies suggest that diurnal fluctuations in isoprene emission may be substantial, leading to inaccuracies in emission estimates at larger scales. We examined diurnal patterns in the basal emission rate of isoprene in red oak (Quercus rubra), eastern cottonwood (Populus deltoides), and eucalyptus (Eucalyptus saligna) and the influence of light and temperature on the magnitude of these diurnal patterns. Maximum …