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Full-Text Articles in Physical Sciences and Mathematics

Rotational Cropping Introducing Tama Ryegrass Renge, (Astragalus Sinicus), Pumpkin (Cucurbita Moschata Var Tecnus) And Horse Bean (Vicia Faba) In Paddy Field, T I. Kawase Jun 2024

Rotational Cropping Introducing Tama Ryegrass Renge, (Astragalus Sinicus), Pumpkin (Cucurbita Moschata Var Tecnus) And Horse Bean (Vicia Faba) In Paddy Field, T I. Kawase

IGC Proceedings (1997-2023)

The author was successful in introducing Tama Rye grass mixed with Renge by surface sowing just after the harvest of rice in paddy fields (in dried up condition). The grasses were cut 3-4 cm long, spread between young plants of rice after transplanting and the paddy field filled with water. Then the grasses covered well for depressing weed growth and contributed as green manures. The author was also successful in introducing grasses in rice fields and producing pumpkin or corn then horse beans in paddy fields after they dried up. This rotational cropping of grass -rice- corn or pumpkin and …


The Comparison Of Different Short-Term Rotation Systems Of Winter Forage Crops With Rice In Subtropical Plain Region Of Southwestern China, U Simon, S R. Zhou, K Mao Jun 2024

The Comparison Of Different Short-Term Rotation Systems Of Winter Forage Crops With Rice In Subtropical Plain Region Of Southwestern China, U Simon, S R. Zhou, K Mao

IGC Proceedings (1997-2023)

The objective of this study was to explore the possibility of growing winter forage crops in the present farming system with simple grain production only in subtropical plain region of southwestern China. The result showed that the four rotation systems i.e. Astragalus sinicus (70%) + Lolium multiflorum (30%) rice, Medicago hispida (75%) + Lolium multiflorum (25%) rice, Lolium multiflorum (20%) + Vicia villosa (80%) rice and Astragalus sinicus (80%) + Brassica napus (20%) rice obtained good forage values (TDOM 3.35-4.12 t/ha, CP 1.12-1.31 t/ha, ME 2.53-3.19 X 104 MJ/ha), at the same time, obtained better rice yields (DW 6.35-7.17 t/ha) …


The Fight For Rice: Understanding How Monte Cristi Will Respond To Dr-Cafta And Climate Change, Scarlette G. Flores Jun 2024

The Fight For Rice: Understanding How Monte Cristi Will Respond To Dr-Cafta And Climate Change, Scarlette G. Flores

Environmental Studies Senior Theses

The Dominican Republic and Central American Free Trade Agreement, or DR-CAFTA, was signed on March 1, 2007 by the United States, the Dominican Republic and six other countries in Central America. The United States set specific tariff schedules to be phased in after twenty years for certain crops, one of which is rice. Rice is one of the most important crops in the Dominican Republic and produced in the northwestern province of Monte Cristi. This area is affected by climate change due to droughts and water shortages. In my research, I investigate how rice farmers and agrochemical companies, two important …


Unlocking Antioxidant Potential: Comparative Analysis Of Sembada 188 And Keladi Rice As Functional Ingredients In Novel Food Production, Mas Munira Rambli, Natasha Azamain, Eng-Tong Phuah Jan 2024

Unlocking Antioxidant Potential: Comparative Analysis Of Sembada 188 And Keladi Rice As Functional Ingredients In Novel Food Production, Mas Munira Rambli, Natasha Azamain, Eng-Tong Phuah

ASEAN Journal on Science and Technology for Development

Rice (Oryza sativa L.) is an essential crop that is a dietary staple for more than half of the world's population. There is currently a movement in consumer behaviour toward healthier food consumption, which is fuelling interest in functional diets like coloured rice. Sembada 188 and Keladi rice are underutilised in Brunei Darussalam and are expected to have functional qualities. A comparison of antioxidant properties between Sembada 188 and Keladi rice was performed in this study. This research produced puffed rice treats prepared by steaming rice, washing, drying for 6-8 hours at 60℃, deep frying for 25 seconds at 180℃, …


Environmental And Agronomic Evaluation Of Struvite In Rice Production Systems, Diego Della Lunga Dec 2023

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 …


Dry Matter Production Of Two Rice Cultivars With Contrasting Root Plasticity Expression Under Different Topographic Conditions Subjected To Soil Moisture Fluctuation, Stella Owusu Nketia, Roel Rodriguez Suralta, Yoshiaka Inukai, Shiro Mitsuya, Mana Kano Nakata, Peter Amoako Ofori, Dinh Thi Ngoc Nguyen, Akira Yamauchi Jun 2023

Dry Matter Production Of Two Rice Cultivars With Contrasting Root Plasticity Expression Under Different Topographic Conditions Subjected To Soil Moisture Fluctuation, Stella Owusu Nketia, Roel Rodriguez Suralta, Yoshiaka Inukai, Shiro Mitsuya, Mana Kano Nakata, Peter Amoako Ofori, Dinh Thi Ngoc Nguyen, Akira Yamauchi

The Philippine Agricultural Scientist

In rainfed lowland rice fields characterized by sloping terrains and the presence of a hardpan in a flat topography, plants are often exposed to soil moisture fluctuation (SMF) stress due to erratic rainfall patterns. Root plasticity is one of the key traits that play important roles in plant adaptation under such conditions. In this study, two contrasting genotypes, KDML105 and IRAT109, were examined to quantify the expression of plasticity in root branching at different positions in the toposequence (TP) and in a flat topography with a hardpan, both without a groundwater table, and subjected to SMF. Results showed that KDML105 …


The Identification Of Genetic Synteny Between Lolium Perenne Chromosome 7 And Rice Chromosome 6 Genomic Regions That Have Major Effects On Heading-Date, I. P. Armstead, L. B. Turner, L. Skøt, I. S. Donnison, M. O. Humphreys, I. P. King Apr 2023

The Identification Of Genetic Synteny Between Lolium Perenne Chromosome 7 And Rice Chromosome 6 Genomic Regions That Have Major Effects On Heading-Date, I. P. Armstead, L. B. Turner, L. Skøt, I. S. Donnison, M. O. Humphreys, I. P. King

IGC Proceedings (1997-2023)

Comparative genetic mapping between plant species has established that there has been a conservation of genomic organisation which reflects evolutionary relationships. The genetic mapping of L. perenne has identified such syntenic relationships with both the Triticeae and rice. The recent publication of the complete sequence of the rice genome has allowed these relationships to be analysed more closely and has raised the possibility of using the rice genome as a template for chromosome landing-based gene identification in related non-model species. The aim of the present work was to map particular markers and genes associated with heading-date in rice in L. …


An In Silico Dna Sequence Comparison Of The Perennial Ryegrass And Rice Genomes, Marty J. Faville Apr 2023

An In Silico Dna Sequence Comparison Of The Perennial Ryegrass And Rice Genomes, Marty J. Faville

IGC Proceedings (1997-2023)

Comparative mapping studies in the family Poaceae, which includes rice (a model species for this family) and perennial ryegrass (PRG) have indicated macro-colinearity of genes is generally conserved across different genomes. Genome mapping of simple sequence repeat markers derived from expressed sequence tags (EST-SSRs) for PRG (Faville et al., 2004) provides a vehicle for DNA sequence-based matching of mapped PRG genes to orthologous positions in the rice genome, which can be used to establish comparative relationships between these species’ genomes. We have initiated such an analysis using an EST-SSR-based PRG genome map. Our objective was to assess this in …


Diagnosing Excess Nitrogen In Rice Using Post-Season Tissue Samples, Kyle Hoegenauer Dec 2022

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 Dec 2022

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 Aug 2022

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 …


The Three-Way Interplay Among Early Life Exposures, The Gut Microbiome, And Outcomes In Infancy, Yuka Moroishi Jan 2022

The Three-Way Interplay Among Early Life Exposures, The Gut Microbiome, And Outcomes In Infancy, Yuka Moroishi

Dartmouth College Ph.D Dissertations

The bidirectional relationship between the gut microbiome and immune system plays an important role in host immune status: the immune system provides the gut microbiome the optimal environment to thrive in, and the gut microbiome helps regulate the immune system. This relationship is especially important in infants, whose immune system is still premature and rely on innate immunity.

We investigated the three-way interplay among early-life exposures, the developing gut microbiome, and outcomes in infancy from the general population in New Hampshire, US. We used prospective cohort data from the New Hampshire Birth Cohort study to 1) determine whether timing of …


Addressing Rice Waste In University Cafeterias Using Material Flow Analysis And System Dynamics Modeling, Abigail Marie T. Favis, Charlotte Kendra Z. Gotangco-Gonzales, Ana Erika Lareza Jan 2022

Addressing Rice Waste In University Cafeterias Using Material Flow Analysis And System Dynamics Modeling, Abigail Marie T. Favis, Charlotte Kendra Z. Gotangco-Gonzales, Ana Erika Lareza

Environmental Science Faculty Publications

Food waste has emerged as one of the focus areas in sustainability research. At the Ateneo de Manila University, previous studies have found that food waste is composed mainly of rice. This study, therefore, analyzed cafeteria rice systems in the university through a material flow analysis (MFA) to identify key factors for formulating effective rice waste reduction techniques and then applied the results toward developing system dynamics (SD) models as tools for decision-making. The MFA found that the total mass of produced known rice waste was 49.48 kg/d. The largest sources of rice wastes were the upstream processes of the …


Evapotranspiration In Mid-South Rice Production, Colby Wade Reavis Dec 2021

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 Dec 2021

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 …


Elevated Atmospheric Co2 Concentration Triggers Redistribution Of Nitrogen To Promote Tillering In Rice, Juan Zhou, Yingbo Gao, Junpeng Wang, Chang Liu, Zi Wang, Minjia Lv, Xiaoxiang Zhang, Yong Zhou, Guichun Dong, Yulong Wang, Jianye Huang, Dafeng Hui, Zefeng Yang, Youli Yao May 2021

Elevated Atmospheric Co2 Concentration Triggers Redistribution Of Nitrogen To Promote Tillering In Rice, Juan Zhou, Yingbo Gao, Junpeng Wang, Chang Liu, Zi Wang, Minjia Lv, Xiaoxiang Zhang, Yong Zhou, Guichun Dong, Yulong Wang, Jianye Huang, Dafeng Hui, Zefeng Yang, Youli Yao

Biology Faculty Research

Elevated atmospheric CO2 concentration (eCO2) often reduces nitrogen (N) content in rice plants and stimulates tillering. However, there is a general consensus that reduced N would constrain rice tillering. To resolve this contradiction, we investigated N distribution and transcriptomic changes in different rice plant organs after subjecting them to eCO2 and different N application rates. Our results showed that eCO2 significantly promoted rice tillers (by 0.6, 1.1, 1.7, and 2.1 tillers/plant at 0, 75, 150, and 225 kg N ha−1 N application rates, respectively) and more tillers were produced under higher N application rates, …


Estimating Irrigation In Rice Fields With A Water Balance Approach, Kristen Trinh May 2021

Estimating Irrigation In Rice Fields With A Water Balance Approach, Kristen Trinh

Biological and Agricultural Engineering Undergraduate Honors Theses

Global food production must increase to meet the demand associated with increased population growth, so irrigation water use will continue to rise. Therefore, it is important to monitor water usage particularly when an irrigation flowmeter is unavailable. A field water balance was created for a selection of rice fields in East-central Arkansas under observation in 2018 and 2019. From those, irrigation inputs are deduced from the water balance alone. First, each field had sensors that collected water table level (WTL) data. Next, other water inputs and outputs such as precipitation and evapotranspiration (ET) were collected from two modeled sources. The …


Starter Nitrogen Source And Preflood Nitrogen Rate Effects On Rice Grown On Clay Soils, Linda Rachelle Martin May 2021

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 Jan 2021

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 Jul 2020

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 …


Development Of A Mobile Device For Drying Paddy, Botirali R. Bekkulov Jun 2020

Development Of A Mobile Device For Drying Paddy, Botirali R. Bekkulov

Scientific Bulletin. Physical and Mathematical Research

The author of the article describes the results of scientific research aimed at creating a patented new design of a mobile drum device and ensuring an increase in the amount of paddy due to high-quality drying by substantiating its parameters. Firstly, an analysis of scientific research and patent information materials of existing devices for drying sludge working in a convective way, the existing advantages and the main disadvantages of existing devices are determined. Based on the analysis, the requirements of the newly developed device for drying the paddy are formed, theoretical research is carried out, the purpose of which was …


Consumer Preferences For Sustainable Rice Practices In Nigeria, Glory Esohe Okpiaifo Aug 2019

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 …


Method Of Visualsimulation Of Rice Leaf Color, Hongyun Yang, Aizhen Sun, Wenji Yang, Huojiao He Jan 2019

Method Of Visualsimulation Of Rice Leaf Color, Hongyun Yang, Aizhen Sun, Wenji Yang, Huojiao He

Journal of System Simulation

Abstract: A color rendering method for rice leaves based on SPAD data distribution image was presented. Rice leaf image was collected and SPAD value was measured by field rice sample test. The relationship model between SPAD values and RGB value of leaf image was analyzed and constructed, and the R2 was 0.932 8, 0.833 1, 0.562 3 respectively. This showed that there was a correlation between SPAD and the red and green color of the leaf image. By the SPAD data distribution image, the spatial distribution of SPAD value on the leaf surface is described. The leaf surface color …


Evaluation Of Soybean Maturity Group And Planting Date In A Soybean-Rice Rotation On Overall Crop Productivity, Carrie Ortel Dec 2018

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 Aug 2018

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 …


Nitrous Oxide Emissions From Rice Production On A Silt-Loam Soil In Arkansas, Casey Rector May 2018

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 …


Sustainable Intensification Of Agriculture: Opportunities And Challenges For Food Security And Agrarian Adaptation To Environmental Change In Bangladesh, Aaron Michael Shew May 2018

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 May 2018

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 …


Development And Characterization Of Rice Genotypes For Water Use Efficiency And Drought Resistance, Anuj Kumar Dec 2017

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 …


The Effect Of Preflood Nitrogen And Flood Establishment Timing On Rice Development, Nitrogen Uptake And Grain Yield, Tyler Richmond Dec 2017

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 …