Physical Sciences and Mathematics Commons^™

Environmental And Agronomic Evaluation Of Struvite In Rice Production Systems, Diego Della Lunga

Graduate Theses and Dissertations

Furrow-irrigation constitutes an alternative water regime that has been increasingly adopted in Arkansas. Among the management of nutrients in furrow-irrigated systems, phosphorus (P) represents a substantial challenge. The environmental sustainability of rice (Oryza sativa) production systems needs to be evaluated across different water regimes and fertilizer-P sources. Therefore, the objectives of the following studies were to: i) evaluate season-long carbon dioxide (CO2) and methane (CH4) emissions and global warming potential (GWP) under different tillage treatments [i.e., conventional tillage (CT) and no-tillage (NT)] and at different site positions (i.e., up-, mid-, down-slope) along the predominant slope of a production-scale, furrow-irrigated rice …

Diagnosing Excess Nitrogen In Rice Using Post-Season Tissue Samples, Kyle Hoegenauer

Graduate Theses and Dissertations

Proper nitrogen (N) management in rice production can be difficult to achieve without the aid of tools such as soil and tissue tests. There are no tests currently available to rice producers that determine whether N has been managed properly throughout the season or that detect instances of over fertilization. Rice stalk samples were collected from N response trials within 3 days of harvest from the primary Arkansas rice growing region in 2016-2018. Stalk samples were analyzed for N concentration through a KCl extraction and spectrofluorometric quantification. Samples analyzed with leaf material intact contained statistically different N concentrations than samples …

Nitrogen Management In Rice Under Suboptimal Soil Conditions, Payton Suzanne Rhea

Graduate Theses and Dissertations

In Mid-South rice (Oryza sativa, L.) production, nitrogen (N) fertilizer management for pureline varieties is most often recommended as a single preflood (SPF) or two-way split (2WS) application in a direct-seeded, delayed-flood system. Most of the N fertilizer is typically applied at the four- to six-leaf stage onto dry soil, and the second application, if necessary, into the floodwater during early reproductive growth stages (referred to as midseason). Environmental factors frequently prohibit growers from applying early N fertilizer under optimal dry soil conditions. A study was conducted to determine the best N fertilization management practices to utilize in rice when …

The Effect Of Water Management And Ratoon Rice Cropping On Methane Emissions And Harvest Yield In Arkansas, Marguerita Leavitt

Graduate Theses and Dissertations

Sustainable intensification of rice farming is crucial to meeting human food needs while reducing environmental impacts. Rice produces 8% of all anthropogenic CH4, which is a potent greenhouse gas. CH4 emissions can potentially be reduced by cultivation practices that minimize the number of days the fields are saturated, such as dry-seeding instead of water-seeding and irrigation using the alternate wetting and drying (AWD) technique instead of delayed, continuous flooding (DF). Ratoon cropping, wherein a second crop of rice is grown from the harvested stubble of the first crop, can be used to produce additional yield with minimal labor, but may …

Evapotranspiration In Mid-South Rice Production, Colby Wade Reavis

Graduate Theses and Dissertations

Rice provides much needed sustenance to a large portion of the global population, particularly in the developing world. With stress placed on food production systems under the reality of climate change and an increasing global population, rice production systems require solutions to a number of issues, including a limited water supply. As producers explore new strategies for conserving local water resources to continue to maintain yields, new irrigation strategies and technologies are being developed and validated for use at commercial production scales. Alternate wetting and drying (AWD) is an irrigation practice that provides water savings through the capture of rainfall …

Data Analytics For Sustainable Food And Agriculture Systems, Megan Lord Reavis

Graduate Theses and Dissertations

The increasing concentration of anthropogenic greenhouse gases in the atmosphere is altering the climate, posing a serious threat to global agriculture and food security. Agriculture and food production contribute a quarter of all GHG emissions produced, so there is a critical need to limit emissions in this area while increasing food production to feed the anticipated 10 billion people by 2050. To address the needs of the future, data-driven solutions are needed to guide decision-making and provide support for actionable climate mitigation and survival strategies. Research efforts must be focused on analyzing problems on multiple scales, identifying new ways to …

Starter Nitrogen Source And Preflood Nitrogen Rate Effects On Rice Grown On Clay Soils, Linda Rachelle Martin

Graduate Theses and Dissertations

Seedling rice (Oryza sativa L.) grown on clayey-textured soils generally develops slowly as compared to loamy-textured soils. Our research examined the effects of starter-N source and preflood-N rates on canopy closure, total aboveground N uptake, and grain yield of rice grown on clayey-textured soils. Eleven field trials were established in Arkansas and Mississippi including five trials with a hybrid cultivar and six trials using a pure-line cultivar. Starter-N sources included no starter-N (NONE), ammonium sulfate (AMS), diammonium phosphate (DAP), and urea (UREA) applied at 24 kg N ha-1 at the rice 2-leaf stage and five preflood-N rates ranging from 0-224 …

Evaluation Of Nitrous Oxide Emissions From Furrow-Irrigated Rice On A Silt-Loam Soil In Arkansas, Jordan M. Slayden

Graduate Theses and Dissertations

As the number one rice (Oryza sativa)-producing state in the United States, Arkansas also ranks fourth as the largest user of groundwater. Recently, due to the development of drought- resistant hybrid cultivars, the furrow-irrigated rice production system has become an increasingly popular alternative to traditional flood-irrigated production with respect to conserving groundwater and maintaining yield. However, other environmental parameters, like greenhouse gas emissions, specifically nitrous oxide (N2O), have yet to be evaluated under furrow-irrigated rice. The objectives of this study were to i) evaluate the effects of site position (i.e., up-, mid-, and down-slope) and tillage treatment [i.e., conventional tillage …

Rice Fortification By Parboiling In Limited-Water Soaking To Alleviate Mineral And Vitamin Deficiency, Annegret Jannasch

Graduate Theses and Dissertations

Fortification of rice by parboiling is considered a potential alternative to currently available fortification technologies to produce rice with higher mineral and vitamin content significantly contributing to nutrient intake in populations with high prevalence of micronutrient deficiencies. Higher nutrient retention rates and improved sensory characteristics are advantages of fortified parboiled rice compared to fortified rice obtained by currently used fortification technologies including dusting, coating, and extrusion. However, conventional parboiling processes employ excess water that presents an environmental hazard if discarded without treatment. Thus, the objective of this study was to evaluate a limited-water soaking method for the fortification of rice …

Consumer Preferences For Sustainable Rice Practices In Nigeria, Glory Esohe Okpiaifo

Graduate Theses and Dissertations

Improving the sustainability of rice production is important given its position as a global staple and its environmental footprint. The adoption of sustainable practices can generate positive externalities such as lower environmental pollution and improved working conditions for rice industry workers that could be capitalized via the design of consumer-based marketing strategies. The Sustainable Rice Platform (SRP) initiative aims at advancing the adoption of sustainable practices in rice production. We assess consumers’ perceptions of the SRP sustainability indicators using the Best-Worst Scaling approach to rank SRP sustainability attributes according to their preference shares and examine the effects of demographic characteristics …

Evaluation Of Soybean Maturity Group And Planting Date In A Soybean-Rice Rotation On Overall Crop Productivity, Carrie Ortel

Graduate Theses and Dissertations

Little is known about the effects of soybean (Glycine max L.) management techniques on soil-nitrogen (N) credit development and its impact on the subsequent rice (Oryza sativa L.) crop’s success. This study was conducted to determine how soybean maturity group (MG) and planting date effect overall soybean productivity and its influence on the following rice crop. Various soybean planting dates (optimum and late) and MGs (3.5, 4.7, 5.4, and 5.6) were grown and followed in rotation with a rice crop. Six rates of pre-flood fertilizer-N (0, 44, 89, 134, 179, 224 kg N ha-1) were applied to the rice crop. …

Methane Emissions From Rice Production On A Silt-Loam Soil In Arkansas, Joshua Jeffry Humphreys

Graduate Theses and Dissertations

Methane (CH4) emissions from rice (Oryza sativa L.) production are a source of concern in the environmental and agricultural communities. New and/or revised agronomic methodologies will be needed to identify production practice combinations that reduce CH4 emissions without decreasing yields. The objective of this multi-year study was to evaluate the effects of water management (i.e., full-season flood and mid-season drain) (2015), cultivar (i.e., pure-line cultivar ‘LaKast’ and the RiceTec hybrid “XP753”) (2015), soil organic matter (SOM) concentration (2016), and tillage [conventional tillage (CT) and no-tillage (NT)] and urea-based fertilizers [N-(n-butyl) thiophosphoric triamide (NBPT)-coated urea and non-coated urea] (2017) on CH4 …

Sustainable Intensification Of Agriculture: Opportunities And Challenges For Food Security And Agrarian Adaptation To Environmental Change In Bangladesh, Aaron Michael Shew

Graduate Theses and Dissertations

This dissertation investigates three unique aspects of sustainable agricultural intensification (SAI) in the context of Bangladeshi rice production. The first article presents a qualitative analysis of SAI and farmer surveys in the embanked polder region of coastal Bangladesh. The second article investigates the global food security and environmental impacts of already adopted High Yielding Variety (HYV) rice and double-cropped rice systems in Bangladesh using a spatial partial equilibrium trade model and a Life Cycle Assessment (LCA). The final article demonstrates a remote sensing methodology for monitoring dry season rice production at 30 m resolution in Bangladesh using a harmonic time …

Soil Properties That Influence The Occurrence Of Hydrogen Sulfide Toxicity In Rice Fields, Julia Marie Fryer

Graduate Theses and Dissertations

Rice (Oryza sativa L.) producers face many challenges throughout each growing season. Hydrogen sulfide (H2S) toxicity is a physiological disorder where sulfate (SO42-) is excessively reduced to the toxic gas, H2S. This can reduce yield and, in severe cases, result in crop death. The main research objectives were to: i) understand chemical and physical characteristics in soils prone to H2S toxicity, ii) determine influential soil characteristics on the incidence of H2S toxicity, iii) determine ammonium sulfate ((NH4)2SO4) fertilizer additions influence on H2S toxicity, and iv) predict when and where H2S will occur. Three greenhouse experiments were conducted using Arkansas field …

Nitrous Oxide Emissions From Rice Production On A Silt-Loam Soil In Arkansas, Casey Rector

Graduate Theses and Dissertations

Rice (Oryza sativa L.) is a common crop grown in Arkansas under flooded-soil conditions. The saturated to nearly saturated soil makes rice production an ideal environment for the production of potent greenhouse gases, such as nitrous oxide (N2O). The objectives of this study were to i) evaluate the impact of water management practice (full-season-flood and intermittent-flood) and cultivar (pure-line and hybrid) on N2O fluxes, season-long N2O emissions, and global warming potential (GWP; 2016) and ii) evaluate the impact of tillage practice [conventional tillage and no-tillage (NT)] and type of urea fertilizer [ N-(n-butyl) thiosphosphoric triamide (NBPT)-coated and non-coated urea] on …

The Effect Of Preflood Nitrogen And Flood Establishment Timing On Rice Development, Nitrogen Uptake And Grain Yield, Tyler Richmond

Graduate Theses and Dissertations

Urea-N fertilizer is typically applied at the 5-leaf stage to rice (Oryza sativa L.) grown in a dry-seeded, delayed-flood production system. How long the preflood-N can be delayed without adverse effects on yield potential is poorly understood. The research objective was to determine the effects of preflood-N application and flood establishment timing on aboveground-N content, 50% heading, yield components, and grain yield. Trials were established on silt loam soils at the Pine Tree Research Station (PTRS) and Rice Research and Extension Center (RREC) during 2015 and 2016. Urea-N was applied at 0, 45, 90, 135, and 180 kg N ha-1 …

Development And Characterization Of Rice Genotypes For Water Use Efficiency And Drought Resistance, Anuj Kumar

Graduate Theses and Dissertations

Rice, the second largest staple food crop, uses 30% of global fresh water to complete its life cycle worldwide. Water deficits worldwide have become a serious problem affecting rice growth and ultimately grain yield. To solve the water problem globally, improvement of water use efficiency (WUE) and other drought resistance (DR) traits in rice genotypes would be a useful strategy using advanced genomics tools. In this study, our objectives were to 1) analyze phenotypes of the USDA rice mini-core collection (URMC) for WUE and DR related traits, 2) correlate drought response phenes for physiological traits and grain yield in the …

Validation Of Soil-Test-Based Phosphorus And Potassium Fertilizer Recommendations For Rice And Soybean, Matthew Scott Fryer

Graduate Theses and Dissertations

The science of soil-testing for nutrient management and fertilizer recommendations is widely accepted among scientists and agronomists. Although this science is unsurpassed in predicting soil nutrient availability, soil-test interpretations are seldom validated. Major research objectives for irrigated soybean [Glycine max (L.) Merr.] and direct-seeded, delayed-flood rice (Oryza sativa L.) were to: i) validate the accuracy of Mehlich-3 soil-test P (STP) and K (STK) interpretations and ii) published critical tissue-P and -K interpretations in predicting the yield response to fertilizer at different significance levels (p≤0.05 to 0.25), iii) examine how seed nutrient concentrations are influenced by fertilization and crop response to …

Methane Emissions From Direct-Seeded, Delayed-Flood Rice Grown On A Clay Soil, Alden Daniel Smartt

Graduate Theses and Dissertations

Due to the production of methane (CH4) under flooded-soil conditions, rice (Oryza sativa L.) cultivation is a major contributor to agricultural CH4 emissions. Studies examining CH4 emissions from rice have only recently been initiated in Arkansas and no data have been collected from rice produced on clay soils in Arkansas. Therefore, research was conducted in 2012 and 2013 at the Northeast Research and Extension Center in Keiser, Arkansas to examine the factors affecting CH4 emissions from rice produced on a Sharkey clay (very-fine, smectitic, thermic Chromic Epiaquerts). The objectives of this study were to determine: 1) the effect of vegetation …

Disaggregating The Effect Of Drought And Heat Stress During Flowering On Spikelet Fertility In Rice, Lisa Straussberger

Graduate Theses and Dissertations

Due to rice’s wide geographic distribution, extending from 50°N to 35°S, rice is

forecasted to be the most vulnerable crop to warming global climates. Previous studies have

predicted lower rice yields and increasing rice yield variability due to higher frequencies of heat

stress events, and a higher variability in precipitation patterns due to global warming. As such,

understanding the effects of drought and heat stress intensity and frequency on rice yields is of

upmost importance to feeding the growing global population.

Given that drought and high-temperature stress often occur together, it is essential to

disaggregate the two individual stressors and …

Methane Emissions And Ammonia Volatilization From Drill-Seeded, Delayed-Flood Rice On A Silt-Loam Soil In Arkansas, Christopher Wade Rogers

Graduate Theses and Dissertations

The Environmental Protection Agency (EPA) currently uses a single methane (CH4) emissions factor of 160 kg CH4-C ha-1 for a primary rice (Oryza sativa L.) crop. The emissions factor is based on studies that do not adequately represent current management practices in Arkansas. Another concern is pre-flood fertilizer nitrogen (N) management, as the common N source, urea, is prone to loss via ammonia (NH3) volatilization. Thus, the objective of this research was to investigate trace gas emissions from rice on a silt-loam soil, including CH4 emissions as influenced by nitrogen (N) fertilization (i.e., optimal N and no N) in 2011, …

Long-Term Effects Of Rice Rotation, Tillage, And Fertility On Near-Surface Soil Carbon And Nitrogen Cycling, Jill Marie Motschenbacher

Graduate Theses and Dissertations

Rice (Oryza sativa L.)-based cropping systems are different from other row crops due to the flood-irrigation scheme used from about one month after planting to a few weeks prior to harvest. The frequent cycling between anaerobic (i.e., flooding during the growing season) and aerobic (i.e., generally, the remainder of the year) conditions can influence the rate of soil organic matter (SOM) decomposition, which can greatly influence carbon (C) and nitrogen (N) storage and sequestration in the soil over time. Therefore, a study was conducted on a silt-loam soil (fine, smectitic, thermic, Typic Albaqualf) at the Rice Research and Extension Center …

What Factors Influence Consumers' Willingness To Purchase And Consume Carbon-Labeled Rice: A Comparative Study Between Arkansas And Belgium, John A. Kelley

Graduate Theses and Dissertations

Climate change is an issue of growing importance around the globe. As global population increases so does attention focused on human contributions to climate change. One major way humans contribute to climate change is through our diets. Agricultural production is a major source of global greenhouse emissions. It has been estimated that food production is responsible for a large majority of the methane and nitrous oxide which is emitted into our atmosphere each year. Carbon footprint labeling has been developed to give consumers a way to lower their footprint and help lower emissions of greenhouse gasses. At least one retailer, …