Life Sciences Commons^™

Ammonium Phosphate Fertilizers Are A More Effective Phosphorus Source Than Superphosphate For Wheat Grown On Acidic Gravelly Soils, Craig A. Scanlan, Raj Malik, Fien Degryse, Andrew Van Burgel, Mike J. Mclaughlin

Grain and Other Field Crops Research Articles

Selecting the most effective phosphorus (P) fertilizer source is essential for maximizing crop yields. However, there is little information to guide the choice between the widely used soluble granular sources: ammonium phosphates and superphosphates. The aims of this study were to examine whether there are differences in wheat (Triticum aestivum L.) grain yield response to ammonium phosphate and superphosphate fertilizers in field conditions, and if these differences relate to diffusion of P from fertilizer granules. Two field experiments were conducted on acidic gravelly soils in Western Australia where P deficiency occurs to compare wheat growth response to P applied …

Secure Agricultural Futures: Re-Defining And -Imagining Agricultural Water Landscapes In The Us West, Britta L. Schumacher

All Graduate Theses and Dissertations, Fall 2023 to Present

Aridity is swiftly becoming the US West’s new normal. As agricultural communities adjust to persistent growing-season scarcity, they find their livelihoods under increasing threat. This points to the urgency of finding paths toward more secure water futures. A piece of this future puzzle includes water (re-)distribution – taking excess from one place and delivering it to another in need. To begin thinking about (re-)distribution, this dissertation engages with three mixed-methods and multiscale studies. The first study pairs county-level data across the 11 westernmost US states with survey data collected from individual producers in Utah to assess past and current trends …

Agronomic And Economic Evaluation Of Alternative Forage Crops Under Irrigation Technologies And Deficit Irrigation, Shikha Sharma

All Graduate Theses and Dissertations, Fall 2023 to Present

Water is becoming more limited in the western United States, including Utah, so farmers need forage crops that can produce well while using less irrigation water. This study examined how different forage crops respond to reduced irrigation and different irrigation application methods, and whether some crops can provide better economic returns under limited water conditions.

Field studies were conducted at three Utah locations, Cedar City, Logan, and Vernal, from 2020 to 2024. The alternative forage crops included teff, sorghum-sudangrass (sudex), and forage rye. For economic comparison, conventional forage crops included alfalfa, corn, and three-way small grains. Four to five irrigation …

Aegic Blogposts - Grain Supply Chains, Ross Kingwell, Peter Elliott

Grain and other field crops published reports

The Australian Export Grains Innovation Centre (AEGIC) was an independent, not-for-profit organisation established in 2012 by the Western Australian Government and the Grains Research and Development Corporation (GRDC). Its core mission was to increase the value and international competitiveness of Australia’s multibillion-dollar export grains industry. AEGIC ceased operation at the end of 2025.

Early in its history between 20 to 30 staff from the former Western Australian Department of Agriculture were seconded to AEGIC. Following the formation of DPIRD, AEGIC continued to receive substantial annual funding support from DPIRD.

This publication is a legacy document containing collated AEGIC blog posts …

Aegic Blogposts - Grain Pricing, Ross Kingwell, Peter Elliott, Chris Carter

Grain and other field crops published reports

The Australian Export Grains Innovation Centre (AEGIC) was an independent, not-for-profit organisation established in 2012 by the Western Australian Government and the Grains Research and Development Corporation (GRDC). Its core mission was to increase the value and international competitiveness of Australia’s multibillion-dollar export grains industry. AEGIC ceased operation at the end of 2025.

Early in its history between 20 to 30 staff from the former Western Australian Department of Agriculture were seconded to AEGIC. Following the formation of DPIRD, AEGIC continued to receive substantial annual funding support from DPIRD.

This publication is a legacy document containing collated AEGIC blog posts …

Aegic Blogposts - Grain Demand In Key Regions And Countries, Ross Kingwell, Sean Cowman, Peter Elliott, Chris Carter

Grain and other field crops published reports

The Australian Export Grains Innovation Centre (AEGIC) was an independent, not-for-profit organisation established in 2012 by the Western Australian Government and the Grains Research and Development Corporation (GRDC). Its core mission was to increase the value and international competitiveness of Australia’s multibillion-dollar export grains industry. AEGIC ceased operation at the end of 2025.

Early in its history between 20 to 30 staff from the former Western Australian Department of Agriculture were seconded to AEGIC. Following the formation of DPIRD, AEGIC continued to receive substantial annual funding support from DPIRD.

This publication is a legacy document containing collated AEGIC blog posts …

Aegic Blogposts - Grain Demand Overview, Ross Kingwell, Paul Meibusch, Jorge E. Mayer, Richard Williams, Peter Elliott, Chris Carter

Grain and other field crops published reports

The Australian Export Grains Innovation Centre (AEGIC) was an independent, not-for-profit organisation established in 2012 by the Western Australian Government and the Grains Research and Development Corporation (GRDC). Its core mission was to increase the value and international competitiveness of Australia’s multibillion-dollar export grains industry. AEGIC ceased operation at the end of 2025.

Early in its history between 20 to 30 staff from the former Western Australian Department of Agriculture were seconded to AEGIC. Following the formation of DPIRD, AEGIC continued to receive substantial annual funding support from DPIRD.

This publication is a legacy document containing collated AEGIC blog posts …

Aegic Blogposts - Grain Demand: Health And Environmental Issues, Ross Kingwell, Nicholas Thorsager, Chris Carter

Grain and other field crops published reports

The Australian Export Grains Innovation Centre (AEGIC) was an independent, not-for-profit organisation established in 2012 by the Western Australian Government and the Grains Research and Development Corporation (GRDC). Its core mission was to increase the value and international competitiveness of Australia’s multibillion-dollar export grains industry. AEGIC ceased operation at the end of 2025.

Early in its history between 20 to 30 staff from the former Western Australian Department of Agriculture were seconded to AEGIC. Following the formation of DPIRD, AEGIC continued to receive substantial annual funding support from DPIRD.

This publication is a legacy document containing collated AEGIC blog posts …

Aegic Blogposts - Climate Impacts On Grain Production, Ross Kingwell, Nicholas Thorsager, David Stephens, Ian Foster, Imma Farre

Grain and other field crops published reports

The Australian Export Grains Innovation Centre (AEGIC) was an independent, not-for-profit organisation established in 2012 by the Western Australian Government and the Grains Research and Development Corporation (GRDC). Its core mission was to increase the value and international competitiveness of Australia’s multibillion-dollar export grains industry. AEGIC ceased operation at the end of 2025.

Early in its history between 20 to 30 staff from the former Western Australian Department of Agriculture were seconded to AEGIC. Following the formation of DPIRD, AEGIC continued to receive substantial annual funding support from DPIRD.

This publication is a legacy document containing collated AEGIC blog posts …

Aegic Blogposts - Grain Industry Productivity, Ross Kingwell

Grain and other field crops published reports

The Australian Export Grains Innovation Centre (AEGIC) was an independent, not-for-profit organisation established in 2012 by the Western Australian Government and the Grains Research and Development Corporation (GRDC). Its core mission was to increase the value and international competitiveness of Australia’s multibillion-dollar export grains industry. AEGIC ceased operation at the end of 2025.

Early in its history between 20 to 30 staff from the former Western Australian Department of Agriculture were seconded to AEGIC. Following the formation of DPIRD, AEGIC continued to receive substantial annual funding support from DPIRD.

This publication is a legacy document containing collated AEGIC blog posts …

Evaluating The Responses Of Organic Corn Systems To Interseeded Cover Crops, Seeding Rate, And Tillage, Luvina B. Madrid

All Dissertations

Cover crop interseeding offers a potential strategy to increase plant diversity and make better use of above- and belowground resource niches within organic corn production systems. Interseeded cover crops can support agroecosystem sustainability through aboveground biomass production as well as belowground processes mediated by roots, including soil structural improvement, nutrient cycling, biological activity, and carbon storage. However, the success of interseeding depends on selecting cover crop species and management practices that provide these benefits without competing with the crop for water, nutrients, and light. Research studies were conducted to evaluate the effects of interseeded cover crop species, seeding rate, and …

Integrated Soil-Water Processes And Irrigation Management For Agricultural Water Optimization In Semi-Arid Regions, Tejinder Singh

All Graduate Theses and Dissertations, Fall 2023 to Present

Water is one of the most important resources for agriculture in the western United States. In semi-arid regions, farmers depend on irrigation to grow crops, but water supplies are becoming less reliable because of drought, declining snowpack, groundwater depletion, and increasing competition for limited water. Improving agricultural water use is therefore not simply about applying less water. It also requires understanding where water goes after it enters a field, how long it remains available to crops, and how farmers can use that information to make better irrigation decisions. This dissertation follows water through irrigated agricultural systems to better understand how …

A Genetic Analysis Of The Rare Endemic Astragalus Ripleyi Barneby, Juan Antonio Jaramillo-Chico

Master's Theses

Astragalus ripleyi Barneby is a rare endemic species found in the San Luis Valley of the southern portions of the Rocky Mountains in Colorado and New Mexico. Though not federally listed as endangered, the species is on the Bureau of Land Management’s Sensitive Species List, warranting protection and continued management. This study aims to provide information about the genetic health of the species to inform conservation efforts and provide updated management recommendations. A genetic health analysis was conducted investigating the levels of diversity present in the species, how genetic diversity is structured across the known range of the species and …

B.R. Wells Arkansas Rice Research Studies 2025, J. Hardke, X. Sha, N. Bateman

Arkansas Agricultural Experiment Station Research Series

Arkansas is the leading rice producer in the United States. The state represents 45.2% of total U.S. rice production and 45.7% of the total acres planted to rice in 2025. Rice cultural practices vary across the state and across the U.S. However, these practices are also dynamic and continue to evolve in response to changing political, environmental, and economic times. This survey was initiated in 2002 to monitor and record changes in the way Arkansas rice producers approach their livelihood. The survey was conducted by polling county extension agents in each of the counties in Arkansas that produce rice. Questions …

Effects Of Photosynthetic Mode On Growth In Closely Related Tillandsia Species, Jeremy L. Read

Electronic Theses, Projects, and Dissertations

To examine the effects of photosynthetic mode (C3 vs CAM) on plant productivity, subjects of the sister taxa Tillandsia confertiflora (a C3 species) and Tillandsia latifolia (a CAM species) were grown under controlled conditions via growth chamber over 30 weeks. These subjects were divided into non-stressed and drought stress groups. Subjects were compared for total biomass gained or lost over the time period as well as physiological stress measures and CAM activity. The primary conclusion is that usage of CAM does not show major differences or tradeoffs for overall productivity. Future work is needed to clarify if this holds true …

Silviculture For Coastal Forest Resilience: Promoting Forest Regeneration And Managing Invasive Plant Species, Ryan Bohannon

All Dissertations

Coastal forests of the southern United States and the ecosystem services they provide are threatened by an intensifying and interacting suite of disturbances associated with global change. Silvicultural strategies such as enrichment planting, invasive plant management, and browse mitigation treatments can enhance the resilience and adaptive capacity of forests to these threats by promoting sustainable regeneration and recruitment dynamics. To improve our understanding of coastal forest disturbance regimes and their impacts on forest stand dynamics, I conducted a systematic literature review of maritime forest disturbance ecology and identified coastal storms, ungulate browsing pressure, and invasive plants as primary disturbances shaping …

Considerations And Challenges For Oak-Pine Woodland Restoration In The Southern Appalachians, Armin Weise

All Dissertations

Appalachian forests in the southeastern United States are composed of fire-adapted communities. These have historically been burned by native Americans and by lightning-ignited fires, causing widespread ignitions across the landscape for millennia that have shaped the forest and the species within it. Many of the more xeric oak-pine forest systems in the region were more akin to woodlands with open midstories, understocked canopies, and a diverse understory layer of herbaceous species and shrubs. With the decline of Native Americans due to disease and forced removal, fire across the landscape declined, a trend compounded by fire-suppression policies put forth by the …

Towards Improved Stress Resilience, Optimal Growth And Enhanced Biosafety In Transgenic Plants, Xiaotong Chen

All Dissertations

This dissertation investigates biotechnology strategies to improve plant stress resilience, growth, and biosafety in transgenic perennial grasses using creeping bentgrass as a model system. Functional analyses of non-coding RNAs such as miR164 and miR169 showed that regulatory non-coding RNAs influence plant architecture and abiotic stress responses through broad developmental and transcriptional networks, supporting them as valuable engineering targets for complex trait improvement. The dissertation also developed a dual recombinase platform for transgene containment and removal, linking trait engineering with biosafety control. Additionally, the recombinases themselves were examined for their potential impact on heterologous host and were found to reshape plant …

Optimizing Urban Forestry Through Green Infrastructure: Tree Health And Water Retention In Ciudad Juarez Rain Gardens, Tomas Rogelio Lizarraga Ruiz

Open Access Theses & Dissertations

Urban green spaces (UGS) in arid regions face significant challenges due to water scarcity and extreme thermal demand. This study evaluates the efficacy of Nature Based Solutions (NBS), rain gardens and median strips, in enhancing the physiological resilience of urban trees in Ciudad Juárez, Mexico. Using a comparative framework, the research monitored a native evergreen (Dermatophyllum secundiflorum) and an introduced deciduous species (Morus sp.) across six planting treatments. Statistical analysis reveals that green infrastructure (GI) acts as a critical physiological accelerant. Trees situated within rain gardens and medians significantly outperformed those in restricted pot and sidewalk settings, maintaining higher stomatal …

Summaries Of Arkansas Cotton Research 2025, Fred M. Bourland

Arkansas Agricultural Experiment Station Research Series

Planted cotton acreage in Arkansas decreased in 2025 to 520,000 acres compared to 650,000 planted acres in 2024. Arkansas producers harvested 515,000 acres, which was a decrease of 125,000 acres from the 640,000 acres harvested in 2024 (https://www.nass.usda.gov/Quick_Stats/Ag_Overview/stateOverview.php?state=Arkansas&year=2025). The 515,000 harvested acres ranked Arkansas third nationally, trailing only Texas and Georgia in harvested acres (https://esmis.nal.usda.gov/sites/default/release-files/795725/cropan26.pdf). The average cotton yield, as reported by the USDA, was 1,239 lb lint/ac, which ranked fourth nationally, behind California, Louisiana, and Arizona. Arkansas farmers produced an estimated 1.329 million bales, which is a decrease from 1.788 million bales produced in 2024. This production still ranks …

Reconstructing Stand-Age Structure In A Wet Miombo Woodland Using Dendrochronology, Zambia, Clara Tiyembekeze Zulu

All-Inclusive List of Electronic Theses and Dissertations

Dendrochronological research in tropical Africa has remained limited, leaving critical gaps in stand-age structure and climate-growth relationships in seasonally dry tropical woodlands. This study reconstructed stand-age structure and assessed climate sensitivity in the wet Miombo woodland of African Explosives Limited (AEL) forest, Copperbelt Province, Zambia. Field sampling was conducted during four African Dendrochronology Fieldschools (2021-2024) using a Modified Variable Area Transect (MVAT) design across nine plots. The series intercorrelation was 0.351; the average mean sensitivity was 0.423. The oldest tree was 170 years old, and more than 70% of the sampled species showed potential for dendrochronology. Markhamia obtusifolia was the …

Performance Of The Denitrification-Decomposition Model In Simulating Agronomic Properties And N2o Emissions Under Smallholder Climate-Smart Farming Systems, Esphorn Kibet, Collins M. Musafiri, Milka Kiboi, Onesmus K. Ng'etich, David K. Kosgei, Abdirahman Zeila, Franklin Mairura, Felix K. Ngetich

All Peer-Reviewed Publications

The DeNitrification-DeComposition (DNDC) model is a crucial tool for estimating soil greenhouse gas fluxes and understanding soil-plant interactions. This study evaluates the performance of the DNDC model in simulating soil temperature, moisture, crop yield, and nitrous oxide (N2O) fluxes across different land utilization types in Western Kenya. The land utilization types included: i) agroforestry M (agroforestry with Markhamia lutea, ii) sole sorghum, iii) agroforestry L (agroforestry with Leucaena leucocephala), iv) sole maize, and v) grazing Land, each replicated thrice. Fertilizer and manure were applied as part of the management practices, with manure applied at 2t ha⁻¹. Soil greenhouse …

The Influence Of Ecological Pest Management Practices On Pests And Natural Enemies Under A Cabbage–Garden Pea Rotational System In Central Kenya, Peter Nyakundi Mageto, Milka Kiboi, Monicah Mucheru-Muna, Felix Matheri

All Peer-Reviewed Publications

Pest pressure is a major constraint on crop production in Sub-Saharan Africa, where smallholder farmers rely heavily on synthetic pesticides with potential environmental and health risks. Ecological pest management practices (EPMs) have been proposed as sustainable alternatives, although field-based evidence is limited. This study evaluated pest and natural-enemy responses to EPMs in a cabbage–garden pea rotation system over six years (2020–2025) in Central Kenya. Four treatments were assessed: homemade botanical extracts (Botanicals), coriander intercropping (Intercrop), botanical extracts combined with coriander intercropping (Botanicals + Intercrop), and a control. In cabbage, ecological treatments often recorded lower aphid and diamondback moth abundance and …

High Biochar Rate Improves Water Retention In Some Environmentally Sensitive Soils, Samundra Sigdel

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Improving water retention and other hydraulic properties is key to managing soil water and sustaining crop production under fluctuating and extreme weather events. We assessed how wood biochar (836 g C kg^-1) applied at 0, 6.25, 12.5, 25, and 50 Mg ha^-1 affected: i) soil hydraulic properties after 5 years and ii) corn and soybean yield, and biomass production of cereal rye cover crop (CC) and CC mix (cereal rye, radish, and winter pea) in sandy, sloping, and semi-arid soils in the central U.S. Great Plains over 6 years. Biochar affected field saturated hydraulic conductivity (K_{sat …}

Microbes In Pollination Systems: Effects On Pollinator Health, Floral Traits, Nectar Robbing, And Plant Fitness, Valerie Nicole Martin

All Graduate Theses and Dissertations, Fall 2023 to Present

Flowers produce nectar to attract pollinators, but nectar is also a habitat for yeasts and bacteria that arrive via pollinators, robbers, and other visitors. These microbes consume nectar sugars and release byproducts that change the smell and taste of nectar. Whether these changes affect how pollinators find and choose flowers, and whether they ultimately affect how many seeds a plant produces, is not well understood. In this dissertation, I studied how a common nectar yeast and a plant-associated bacterium affect the scent of wildflowers, the behavior of bumble bees and hummingbirds, and plant reproduction in montane meadows in central Colorado. …

Land Condition Standards For The Western Australian Nullarbor Pastoral Region, Peter-Jon A. Waddell, Wayne J. Fletcher

Natural resources published reports

This report outlines the quantitative land condition standards that define acceptable pastoral land condition for the Western Australian part of the Nullarbor, to meet the regulatory requirements of the Land Administration Act 1997 and the Soil and Land Conservation Act 1945.

The Department of Primary Industries and Regional Development is developing regional-level pastoral land condition standards for Western Australia as a critical component of the Framework for sustainable pastoral management – revised edition (Fletcher 2022), the purpose of which is to address the Office of the Auditor General’s recommendations to improve the management of pastoral lands in WA …

Technological Behaviour Of Pellets Containing Dried Green Crop, Christian Furll

IGC Proceedings (1977-2023)

Pelleted dried green crop presents essential advantages compared to chaff and meal as processing forms. Normally, the solidity of the pellets does not exceed the values required by animal feeding. Abrasion resulting from turnover processes is at present too high, particularly for the discharge of bins. Belt conveyors, vibrating conveyors, and bucket elevators are suitable to convey pellets. Storage of pellets over long periods has to be done by respecting prescribed climate conditions. Zones with excessive portion of abraded par­ticles in the storing pile are a preferred cause for self-heating. Slit-type dosing units as well as dosing units equipped with …

Results Of Comparative Investigations Into The Chevving And Ruminating Activities Of The Dairy Cow Fed Dried Forage From Grass And Leguminous Crops, B Piatkowski, S Nagel

IGC Proceedings (1977-2023)

The chewing and ruminating activities were studied of dairy cows fed grass, alfalfa, and straw of different physical forms. An electronic­ally controlled measuring device was applied. When feeding 8 kg of grass hay (32 % crude fibre in dry matter), the ruminating time was 5: 24 and 1 :49 hours (20,712 and 6,982 ruminat­ing movements) for chopped and ground + pelleted forages, respectively. It declined from 1 : 49 to 0: 0 l hours (from 6,929 to 70 move­ments) when hot-air dried alfalfa (23 % crude fibre) was fed in chopped and ground + pelleted forms, respectively. The ruminating time …

Feed Efficiency In Dairy Cows Of Roughages Preserved And Treated In Different Ways, M Zausch, E Boldt

IGC Proceedings (1977-2023)

Trials were conducted with dairy cows to investigate the feed efficiency of grass-clover mixture (wilted silage, silage made of fresh material with addition of foDTiic acid, artifi­cially dried forage, pellets with varying portions of straw). The results obtained allow to draw the following conclusions:

As regards dry matter intake, digestibility, and feed efficiency, grass-dover for wilted silage should be wilted to give a OM content not exceeding 40 %.

Pelleting artificially dried grass-clover mix­ture and its use in mixed rations together with other separately pelleted components should be avoided.

The best feed efficiency is reached when dried grass-clover is converted …

The Influence Of Dried And Ensiled Grass On Rumen Fermen­Tation, J Voigt, B Piatkowski

IGC Proceedings (1977-2023)

Rumen-fistulated cows were used to study the influence of the forage preservation technique on rumen fermentation and holdup time of the feed in the rumen. Cocksfoot (Dactylis glomerata) preserved as wilted silage or dried green crop was fed in the following variants: wilted silage alone; wilted silage + sugar beet + protein supplement; dried green crop alone; dried green crop + sugar beet + protein supplement. As compared with dried green crop, the shares of true protein and sugar in wilted silage were reduced from 9.8 • to 6.4 '.'I􀉧 and from 7.7 to 1.8 %in DM, respectively. In comparison …