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Full-Text Articles in Life Sciences

Herbicide And Additive Impacts On Bradyrhizobium Japonicum Growth In Solution, Joy Amajioyi, Thandiwe Nleya, Senthil Subramanian, Sharon A. Clay Sep 2023

Herbicide And Additive Impacts On Bradyrhizobium Japonicum Growth In Solution, Joy Amajioyi, Thandiwe Nleya, Senthil Subramanian, Sharon A. Clay

Agronomy, Horticulture and Plant Science Faculty Publications

Plant biostimulants include beneficial fungi and bacteria, and are often applied to foliage to improve crop growth, yield, and/or crop quality. Crop improvements due to biostimulant addition may be modest; therefore, solo applications may not be economical or climate smart. However, biostimulants combined with other postemergence treatments, such as herbicides, may provide an alternative application method, if mixtures do not harm the living organism(s). The growth of Bradyrhizobium japonicum, as a biostimulant surrogate, was assessed in solutions of glyphosate [N-(phosphonomethyl)glycine] and dicamba (3,6-dichloro-2-methoxybenzoic acid), with and without common spray additives (ammonium sulfate [AMS] and nonionic surfactant) in laboratory studies over …


Weed-Induced Crop Yield Loss: A New Paradigm And New Challenges, David Horvath, Sharon A. Clay, Clarence J. Swanton, James V. Anderson, Wun S. Chao Jan 2023

Weed-Induced Crop Yield Loss: A New Paradigm And New Challenges, David Horvath, Sharon A. Clay, Clarence J. Swanton, James V. Anderson, Wun S. Chao

Agronomy, Horticulture and Plant Science Faculty Publications

Direct competition for resources is generally considered the primary mechanism for weed-induced yield loss. A re-evaluation of physiological evidence suggests weeds initially impact crop growth and development through resource-independent interference. We suggest weed perception by crops induce a shift in crop development, before resources become limited, which ultimately reduce crop yield, even if weeds are subsequently removed. We present the mechanisms by which crops perceive and respond to weeds and discuss the technologies used to identify these mechanisms. These data lead to a fundamental paradigm shift in our understanding of how weeds reduce crop yield and suggest new research directions …


Auxin-Based Herbicide Program For Weed Control In Auxin Resistant Soybean, Joy Amajioyi, Thandiwe Nleya, Graig Reicks, Janet Moriles- Miller, David Clay, Sharon Clay Oct 2022

Auxin-Based Herbicide Program For Weed Control In Auxin Resistant Soybean, Joy Amajioyi, Thandiwe Nleya, Graig Reicks, Janet Moriles- Miller, David Clay, Sharon Clay

Agronomy, Horticulture and Plant Science Faculty Publications

Soybean [Glycine max (L.) Merr.] cultivars resistant to synthetic auxin herbicides have provided another mode of action for the postemergence broadleaf weed control. This field study was conducted at three South Dakota locations [Northeast, NERF; east-central, ARF; and Southeast, SERF) in 2019 and two locations (ARF and SERF) in 2020. The Enlist E3 and Roundup Ready 2 Xtend cultivars were planted at three dates (early, mid-, and late season) to examine weed control, agronomic characteristics, nodulation, and yield. Preemergence (PRE) treatment was flumioxazin + metribuzin + S-metolachlor + glyphosate + pendimethalin. Two postemergence (POST) treatments, based on cultivar, were compared …


Near Term Challenges For Global Agriculture - Herbicide Resistant Weeds, Sharon Clay May 2021

Near Term Challenges For Global Agriculture - Herbicide Resistant Weeds, Sharon Clay

Agronomy, Horticulture and Plant Science Faculty Publications

Prior to the 1950s weeds were controlled by a wide variety of mechanical and cultural methods with limited use of inorganic chemicals at very high rates (100s kg ha–1). With the advent of selective carbon-based herbicides in the 1950s, herbicide weed management became the norm throughout much of the world using grams to a few kg of active ingredient per ha. However, with the benefits, there are problems. A few resistant weeds were recognized in the 1970s, but today, in 2021, 521 unique cases of resistance have been documented throughout the world. It is imperative for farmers to rethink the …


Abrasive Weeding As A Vehicle For Precision Fertilizer Management In Organic Vegetable Production, Tran Kim Ngan Luong, Frank Forcella, Sharon A. Clay, Michael S. Douglass, Sam E. Wortman Feb 2021

Abrasive Weeding As A Vehicle For Precision Fertilizer Management In Organic Vegetable Production, Tran Kim Ngan Luong, Frank Forcella, Sharon A. Clay, Michael S. Douglass, Sam E. Wortman

Agronomy, Horticulture and Plant Science Faculty Publications

Abrasive weeding is a nonchemical weed control tactic that uses small, gritty materials propelled with compressed air to destroy weed seedlings. Organic fertilizers have been used successfully as abrasive grits to control weeds, but the goal for this study was to explore the effects of fertilizer grit, application rates, and background soil fertility on weeds, plant available nitrogen (N) uptake, and crop yield. Field trials were conducted in organic ‘Carmen’ sweet red pepper (Capsicum annuum) and organic ‘Gypsy’ broccoli (Brassica oleracea var. italica) and treatments included organic fertilizer grit (8N–0.9P–3.3K vs. 3N–3.1P–3.3K), grit application rates (low …


Teosinte (Zea Mays Ssp Parviglumis) Growth And Transcriptomic Response To Weed Stress Identifies Similarities And Differences Between Varieties And With Modern Maize Varieties, S. A. Bruggeman, D. P. Horvath, A. Y. Fennell Dr, J. A. Gonzalez-Hernandez, S. A. Clay Aug 2020

Teosinte (Zea Mays Ssp Parviglumis) Growth And Transcriptomic Response To Weed Stress Identifies Similarities And Differences Between Varieties And With Modern Maize Varieties, S. A. Bruggeman, D. P. Horvath, A. Y. Fennell Dr, J. A. Gonzalez-Hernandez, S. A. Clay

Agronomy, Horticulture and Plant Science Faculty Publications

Transcriptomic responses of plants to weed presence gives insight on the physiological and molecular mechanisms involved in the stress response. This study evaluated transcriptomic and morphological responses of two teosinte (Zea mays ssp parviglumis) (an ancestor of domesticated maize) lines (Ames 21812 and Ames 21789) to weed presence and absence during two growing seasons. Responses were compared after 6 weeks of growth in Aurora, South Dakota, USA. Plant heights between treatments were similar in Ames 21812, whereas branch number decreased when weeds were present. Ames 21789 was 45% shorter in weedy vs weed-free plots, but branch numbers were similar between …


Influence Of Six Herbicides Applied To Silage Corn On Fall Planted Rye And Radish Cover Crop Growth In South Dakota Soils, Sydney Pridie May 2020

Influence Of Six Herbicides Applied To Silage Corn On Fall Planted Rye And Radish Cover Crop Growth In South Dakota Soils, Sydney Pridie

The Journal of Undergraduate Research

Spring preemergence herbicide applications are often used for burndown of existing weeds and residual control, eliminating weed presence during early season crop growth. There has been an increase in the interest in planting cover crops soon after cash crop removal, due to the potential soil and production benefits. However, soil herbicide residuals may result in poor cover crop growth. This study examined the growth of radish (Raphanus sativa) and rye (Secale cereal), species often used as cover crops, in soils that had been treated with residual herbicides about 100 d prior to cover crop planting. The …


Varying Weed Densities Alter The Corn Transcriptome, Highlighting A Core Set Of Weed-Induced Genes And Processes With Potential For Manipulating Weed Tolerance, David P. Horvath, Sharon A. Clay, Stephanie A. Bruggeman, James V. Anderson, Wun S. Chao, Kathleen Yeater Nov 2019

Varying Weed Densities Alter The Corn Transcriptome, Highlighting A Core Set Of Weed-Induced Genes And Processes With Potential For Manipulating Weed Tolerance, David P. Horvath, Sharon A. Clay, Stephanie A. Bruggeman, James V. Anderson, Wun S. Chao, Kathleen Yeater

Agronomy, Horticulture and Plant Science Faculty Publications

The phenological responses of corn (Zea mays L.) to competition with increasing densities of winter canola (Brassica napus L.) as the weedy competitor were investigated. Changes in the corn transcriptome resulting from varying weed densities were used to identify genes and processes responsive to competition under controlled conditions where light, nutrients, and water were not limited. Increasing densities of weeds resulted in decreased corn growth and development and increased the number and expression intensity of competition-responsive genes. The physiological processes identified in corn that were consistently induced by competition with weeds included protein synthesis and various transport functions. …


Using Drones For Precision Agriculture, Jiyul Chang, Madhav P. Nepal Mar 2019

Using Drones For Precision Agriculture, Jiyul Chang, Madhav P. Nepal

iLEARN Teaching Resources

In this teaching module, students will learn what Precision Agriculture is and how to apply drone into Precision Agriculture practices. To use data (images) taken by drone, students will learn the basic theory of Remote Sensing. Using images, students learn how to make NDVI (Normalized Difference Vegetation Index) maps and how to apply drone (remote sensing technique) in agriculture.


Using Abrasive Grit For Weed Management In Field Crops, Michael Carlson, Frank Forcella, Sam Wortman, Sharon A. Clay Sep 2018

Using Abrasive Grit For Weed Management In Field Crops, Michael Carlson, Frank Forcella, Sam Wortman, Sharon A. Clay

Agronomy, Horticulture and Plant Science Faculty Publications

Abrasive grit, applied at high pressure and directed at plant base, can control weeds and increase yield. We evaluated fertilizer [pelletized turkey (Meleagris gallopavo) litter] and non-fertilizer [walnut (Juglans regia) shell] grits for maize and soybean in-row (IR) weed management. Grits were applied at V1 and V5 of maize, and V1 and V3 of soybean. Between-row weed cultivation was done alone (BR), or in combination with grit (I/B), after grit application. Small weeds (<4 >cm) were controlled after grit treatment, but, larger broadleaf weeds, grass weeds (treated when growing points were below ground), and later emerging …


Air-Propelled Abrasive Grit Can Damage The Perennial Weed Quackgrass, Frank Forcella, Daniel Humburg, Samuel E. Wortman, Sharon A. Clay Aug 2018

Air-Propelled Abrasive Grit Can Damage The Perennial Weed Quackgrass, Frank Forcella, Daniel Humburg, Samuel E. Wortman, Sharon A. Clay

Agronomy, Horticulture and Plant Science Faculty Publications

our field experiments were conducted during 2016 and 2017 to evaluate the efficacy of preemergence herbicides to control glyphosate-resistant common ragweed in corn. Dicamba, dicamba/atrazine, mesotrione + atrazine, isoxaflutole + atrazine, saflufenacil/dimethenamid-P, and S-metolachlor/mesotrione/bicyclopyrone/atrazine were the most efficacious herbicides, providing 94%–100% control of GR common ragweed and reducing density and biomass 98%–100%.


Weed Presence Altered Biotic Stress And Light Signaling In Maize Even When Weeds Were Removed Early In The Critical Weed‐Free Period, David P. Horvath, Stephanie Bruggeman, Janet Moriles-Miller, James V. Anderson, Munevver Dogramaci, Brian E. Scheffler, Alvaro G. Hernandez, Michael E. Foley, Sharon Clay Apr 2018

Weed Presence Altered Biotic Stress And Light Signaling In Maize Even When Weeds Were Removed Early In The Critical Weed‐Free Period, David P. Horvath, Stephanie Bruggeman, Janet Moriles-Miller, James V. Anderson, Munevver Dogramaci, Brian E. Scheffler, Alvaro G. Hernandez, Michael E. Foley, Sharon Clay

Agronomy, Horticulture and Plant Science Faculty Publications

Weed presence early in the life cycle of maize (typically, from emergence through the 8 to 12 leaf growth stage) can reduce crop growth and yield and is known as the critical weed‐free period (CWFP). Even if weeds are removed during or just after the CWFP, crop growth and yield often are not recoverable. We compared transcriptome responses of field‐grown hybrid maize at V8 in two consecutive years among plants grown under weed‐free and two weed‐stressed conditions (weeds removed at V4 or present through V8) using RNAseq analysis techniques. Compared with weed‐free plant responses, physiological differences at V8 were identified …


Propelled Abrasive Grit For Weed Control In Organic Silage Corn, Mauricio Erazo-Barradas, Fran Forcella, Dan Humburg Jan 2018

Propelled Abrasive Grit For Weed Control In Organic Silage Corn, Mauricio Erazo-Barradas, Fran Forcella, Dan Humburg

Agronomy, Horticulture and Plant Science Faculty Publications

Weed management in organic farming requires many strategies to accomplish acceptable control and maintain crop yields. This 2-yr field study used air propelled abrasive grit for in-row weed control in organically certified silage corn (Zea mays L.). Corncob grit was applied as a single application at corn vegetative growth stages V1 (one true leaf; numbers correspond to number of true leaves at the corn vegetative stage), V3, or V5 (in 2013) and V3, V5, and V7 (in 2014) and in double and triple combinations at these stages. Between-row weed control was accomplished by flaming or cultivation after the last grit …


Mob Vs. Rotational Grazing: Impact On Forage Use And Artemisia Absinthium, Heidi Reed, Alexander Smart, David E. Clay, Michelle Ohrtman, Sharon A. Clay Jan 2018

Mob Vs. Rotational Grazing: Impact On Forage Use And Artemisia Absinthium, Heidi Reed, Alexander Smart, David E. Clay, Michelle Ohrtman, Sharon A. Clay

Agronomy, Horticulture and Plant Science Faculty Publications

Short duration (≤24 h), high stocking density grazing systems (e.g., mob grazing) mimics historic prairie grazing patterns of American bison (Bison bison), and should minimize selective grazing. We compared mob [125 cow-calf pairs on either 0.65 ha for 12 h; or 1.3 ha for 24 h] vs. rotational [25 cow-calf pairs on 8.1 ha for 20 days starting in mid-May with or without 2,4-D application prior to grazing; and 15 days starting mid-April (no herbicide)] grazing systems based on forage utilization and impact to Artemisia absinthium (absinth wormwood) in a tall grass pasture of Eastern South Dakota. Grass …


Air-Propelled Organic Fertilizer Grits Can Be Used To Control Weeds And Provide Nitrogen, Michael Carlson Jan 2018

Air-Propelled Organic Fertilizer Grits Can Be Used To Control Weeds And Provide Nitrogen, Michael Carlson

Electronic Theses and Dissertations

Weeds are one of the biggest challenges for organic growers because of the alternative weed control methods. Air-propelled abrasive grit management has been reported to control weed seedlings in corn and soybeans while maintaining yield. This research examined the weed control, corn and soybean yields, nitrogen mineralization, and nitrogen yield responses from grits. The grits used in this research included: Phytaboost Plant Food 7-1-2 (soybean meal), Sustane 8-2-4 and 4-6-4 (turkey litters), and two non-fertilizer grits: Agra Grit (walnut shells) and corn cob meal. Field studies were conducted from 2015 to 2017 in Aurora, SD, Beresford, SD and Morris, MN. …


Palmer Amaranth In South Dakota: Growth, Herbicidal Control, And Soybean Yield Loss, Brian Van De Stroet Jan 2018

Palmer Amaranth In South Dakota: Growth, Herbicidal Control, And Soybean Yield Loss, Brian Van De Stroet

Electronic Theses and Dissertations

Palmer amaranth is a growing concern in the United States. Previously thought to only be able to occupy the southern United States, this plant can now be found throughout the northern states as well. Infestations of Palmer amaranth can now be found in South Dakota and is raising many concerns. Palmer amaranth is characterized by large growth and can be highly competitive with many important crops. Soybean is an important crop in South Dakota, as well as the rest of the world, and has not escaped the detrimental aspects of an infestation of Palmer amaranth. The objectives of this study …


Weed Establishment And Persistence After Water Pipeline Installation And Reclamation In The Mixed Grass Prairie Of Western North Dakota, Erin K. Espeland, Lora B. Perkins Dec 2017

Weed Establishment And Persistence After Water Pipeline Installation And Reclamation In The Mixed Grass Prairie Of Western North Dakota, Erin K. Espeland, Lora B. Perkins

Natural Resource Management Faculty Publications

Weeds in reclamations interfere with success by: 1) competing with desirable species seeded during revegetation; 2) preventing recolonization of reclamations by native species; and 3) reducing the integrity of landscapes by expanding from reclamations into adjacent, intact areas. In the Bakken oilfield of western North Dakota, dispersed reclamation activity and increased traffic may provide many opportunities for weeds to spread. To determine the potential for disturbance and reclamation to increase resident weed populations and introduce new weed species, we tracked twenty-one weed (non-native/ruderal/invasive) species over a four-year period after the installation of a 1.8 km livestock water pipeline and subsequent …


Propelled Abrasive Grit Applications For Weed Management In Transitional Corn Grain Production, Mauricio Enzo-Barradas, Claire N. Friedrichsen, Frank Forcella, Dan Humberg, Sharon A. Clay Jan 2017

Propelled Abrasive Grit Applications For Weed Management In Transitional Corn Grain Production, Mauricio Enzo-Barradas, Claire N. Friedrichsen, Frank Forcella, Dan Humberg, Sharon A. Clay

Agronomy, Horticulture and Plant Science Faculty Publications

Weed control is challenging to farmers who are transitioning from production systems that use synthetic herbicides to organic systems. A 2-year field study examined air-propelled corncob grit abrasion for in-row weed control efficacy and effect on corn yield. Grit was applied based on corn vegetative developmental stages with one (V1, V3 or V5), two (V1 + V3, V1 + V5, or V3 + V5), or three (V1 + V3 + V5) applications. Flame-weeding or cultivation was used after the V5 application for between-row weed control. Grit applications decreased in-row weed densities by about 60% (α = 0.05) and biomass up …


Evaluation Of Flame Weeding In Southeastern South Dakota, Benjamin William Arlt Jan 2016

Evaluation Of Flame Weeding In Southeastern South Dakota, Benjamin William Arlt

Electronic Theses and Dissertations

Weed management is the main yield-limiting factor in production of organic crops. Currently, organic producers have limited resources available for in-row weed management. Flame weeding has been recognized for its potential as one part of an integrated approach at weed management in organic systems. Flame weeding uses propane fueled torches to heat plant tissue and denature proteins, thus injuring or destroying the affected tissue. When properly timed, flame weeding can effectively be used for weed control in corn and soybean fields. Corn and soybean have both shown tolerances to flame weeding and minimal yield loss with well-managed and timed flame …


Corncob Grit Application As An Alternative To Control Weeds In Two Crop Production Systems, Mauricio Erazo-Barradas Jan 2016

Corncob Grit Application As An Alternative To Control Weeds In Two Crop Production Systems, Mauricio Erazo-Barradas

Electronic Theses and Dissertations

Weed management is one of the most challenging production problems in organic cropping systems because of limited weed control methods. Grits, derived from agricultural residues, have been demonstrated to control weed seedlings selectively in corn. This research examined weed efficacy and crop yield of an integrated air-propelled abrasive corncob grit (for in-row weed control) at varying timings and frequencies and flame-weeding or cultivation (for between-row weed control) system in two corn production systems. In the first study efficacy of weed control was assessed with this approach in an organic corn silage production system established in Morris, MN in 2013 and …


Morphologic And Transcriptomic Response To Weed Pressure In Multiple Maize (Zea Mays L.) Selections And Teosinte (Zea Mays L. Ssp Parviglumis) Lines, Stephanie A. Bruggeman Jan 2016

Morphologic And Transcriptomic Response To Weed Pressure In Multiple Maize (Zea Mays L.) Selections And Teosinte (Zea Mays L. Ssp Parviglumis) Lines, Stephanie A. Bruggeman

Electronic Theses and Dissertations

Sweet corn (Zea mays L. convar. saccharata var. rugosa) and modern dent variants (field maize, Zea mays L. indentata) have varying degrees of weed tolerance (ability to maintain yield under weed stress). Maize retains ~30% of its ancestral teosinte’s (Zea mays ssp parviglumis) genetic base. Transcriptomic response to weed pressure in maize and teosinte can lead to manipulation of the maize genome to minimize crop yield loss due to weed presence. In maize and teosinte under weed-free and weedstressed conditions, the objectives of this study were: 1) to evaluate transcriptomic responses of 2 teosinte lines; 2) …


Identification Of Differential Agronomic Traits In Early Stage Teosinte, Flint, Dent, And Sugar (Sweet) Corn Varieties In Competition With Weeds, S.A. Hansen, S. A. Clay, David Horvath, S. Flint-Garcia Jan 2014

Identification Of Differential Agronomic Traits In Early Stage Teosinte, Flint, Dent, And Sugar (Sweet) Corn Varieties In Competition With Weeds, S.A. Hansen, S. A. Clay, David Horvath, S. Flint-Garcia

Agronomy, Horticulture and Plant Science Faculty Publications

Weed competition reduces corn yield. Today’s corn monoculture relies heavily on herbicide inputs to maintain yield. However, teosinte, corn’s ancestor, was successfully grown in mixed production systems. Harnessing genes and traits that allow teosinte to be a better competitor but which may have been lost during corn domestication could help producers reduce herbicide inputs and maintain yield. The first step to finding those genes is to identify varieties of corn and lines of teosinte that have a higher tolerance of weeds or greater weed suppressive ability. Five introductions of teosinte and 14 varieties of corn (including dent, heritage, and sweet …


Seed Burial Physical Environment Explains Departures From Regional Hydrothermal Model Of Giant Ragweed (Ambrosia Trifida) Seedling Emergence In U.S. Midwest, Adam S. Davis, Sharon Clay, John Cardina, Frank Forcella, John Lundquist, Christy Sprague Sep 2013

Seed Burial Physical Environment Explains Departures From Regional Hydrothermal Model Of Giant Ragweed (Ambrosia Trifida) Seedling Emergence In U.S. Midwest, Adam S. Davis, Sharon Clay, John Cardina, Frank Forcella, John Lundquist, Christy Sprague

Agronomy, Horticulture and Plant Science Faculty Publications

Robust predictions of weed seedling emergence from the soil seedbank are needed to aid weed management. A common seed accession (Illinois) of giant ragweed was buried in replicate experimental gardens over 18 site years in Illinois, Michigan, Kansas, Nebraska, Ohio, and South Dakota to examine the importance of site and climate variability by year on seedling emergence. In a nonlinear mixed-effects modeling approach, we used a flexible sigmoidal function (Weibull) to model giant ragweed cumulative seedling emergence in relation to hydrothermal time accumulated in each site-year. An iterative search method across a range of base temperature (Tb ) and base …


Local Conditions, Not Regional Gradients, Drive Demographic Variation Of Giant Ragweed (Ambrosia Trifida) And Common Sunflower (Helianthus Annuus) Across Northern U.S. Maize Belt, Sam E. Wortman, Adam S. Davis, Brian J. Schutte, John L. Lindquist, John Cardina, Joel Felix, Christy L. Sparague, Anita Dille, Analiza H.M. Ramirez, Graig Reicks, Sharon A. Clay Sep 2012

Local Conditions, Not Regional Gradients, Drive Demographic Variation Of Giant Ragweed (Ambrosia Trifida) And Common Sunflower (Helianthus Annuus) Across Northern U.S. Maize Belt, Sam E. Wortman, Adam S. Davis, Brian J. Schutte, John L. Lindquist, John Cardina, Joel Felix, Christy L. Sparague, Anita Dille, Analiza H.M. Ramirez, Graig Reicks, Sharon A. Clay

Agronomy, Horticulture and Plant Science Faculty Publications

Knowledge of environmental factors influencing demography of weed species will improve understanding of current and future weed invasions. The objective of this study was to quantify regional-scale variation in vital rates of giant ragweed and common sunflower. To accomplish this objective, a common field experiment was conducted across seven sites between 2006 and 2008 throughout the north central U.S. maize belt. Demographic parameters of both weed species were measured in intra- and interspecific competitive environments, and environmental data were collected within site-years. Site was the strongest predictor of belowground vital rates (summer and winter seed survival and seedling recruitment), indicating …


Microarray And Growth Analyses Identify Differences And Similarities Of Early Corn Response To Weeds, Shade, And Nitrogen Stress, Janet Moriles, Stephanie Hansen, David P. Horvath, Graig Reicks, David E. Clay, Sharon A. Clay Jun 2012

Microarray And Growth Analyses Identify Differences And Similarities Of Early Corn Response To Weeds, Shade, And Nitrogen Stress, Janet Moriles, Stephanie Hansen, David P. Horvath, Graig Reicks, David E. Clay, Sharon A. Clay

Agronomy, Horticulture and Plant Science Faculty Publications

Weed interference with crop growth is often attributed to water, nutrient, or light competition; however, specific physiological responses to these stresses are not well described. This study's objective was to compare growth, yield, and gene expression responses of corn to nitrogen (N), low light (40% shade), and weed stresses. Corn vegetative parameters from V2 to V12 stages, yield parameters, and gene expression using transcriptome (2008) and quantitative polymerase chain reaction (qPCR) (2008/09) analyses at V8 were compared among the stresses and with nonstressed corn. N stress did not affect vegetative parameters, although grain yield was reduced by 40% compared with …


The Influence Of Biochar Production On Herbicide Sorption Characteristics, Sharon A. Clay, Douglas D. Malo Jan 2012

The Influence Of Biochar Production On Herbicide Sorption Characteristics, Sharon A. Clay, Douglas D. Malo

Agronomy, Horticulture and Plant Science Faculty Publications

Biochar is the by-product of a thermal process conducted under low oxygen or oxygen-free conditions (pyrolysis) to convert vegetative biomass to biofuel (Jha et al., 2010). There are a wide variety of end-products that can be manufactured depending on processing parameters and initial feedstocks (Bridgewater, 2003). The pyrolytic process parameters such as temperature, heating rate, and pressure can change the recovery amounts of each end-product, energy values of the bio-oils, and the physico-chemical properties of biochar (Yaman, 2004).


Early Season Weed Suppression In Buckwheat Using Clopyralid, Ona Sakaliene, Sharon A. Clay, William C. Koskinen, Gediminas Almantas Dec 2008

Early Season Weed Suppression In Buckwheat Using Clopyralid, Ona Sakaliene, Sharon A. Clay, William C. Koskinen, Gediminas Almantas

Agronomy, Horticulture and Plant Science Faculty Publications

Currently there are no herbicides registered for direct application to buckwheat for broadleaf weed control. This 4-yr Lithuanian study examined weed control using several rates of clopyralid alone or combined with a single rate of desmedipham. Most applications were applied at the 1-leaf stage of crop growth, however, one rate of clopyralid was applied pre-emergence (PRE) in 2 of the 4 yr. Buckwheat injury was evident within a few days after application (or emergence) with all treatments, but by harvest, no symptoms were evident. In the 2 yr with greatest weed densities, densities were reduced with increasing clopyralid rates alone …


Early Season Weed Suppression In Buckwheat Using Clopyralid, Ona Sakaliene, Sharon A. Clay, William C. Koskinen, Gediminas Almantas Jan 2008

Early Season Weed Suppression In Buckwheat Using Clopyralid, Ona Sakaliene, Sharon A. Clay, William C. Koskinen, Gediminas Almantas

Agronomy, Horticulture and Plant Science Faculty Publications

Currently there are no herbicides registered for direct application to buckwheat for broadleaf weed control. This 4-yr Lithuanian study examined weed control using several rates of clopyralid alone or combined with a single rate of desmedipham. Most applications were applied at the 1-leaf stage of crop growth, however, one rate of clopyralid was applied pre-emergence (PRE) in 2 of the 4 yr. Buckwheat injury was evident within a few days after application (or emergence) with all treatments, but by harvest, no symptoms were evident. In the 2 yr with greatest weed densities, densities were reduced with increasing clopyralid rates alone …


Common Waterhemp Growth And Fecundity As Influenced By Emergence Date And Competing Crop, E. Uscanga-Mortera, S. Clay, F. Forcella, J. Gunsolus Aug 2007

Common Waterhemp Growth And Fecundity As Influenced By Emergence Date And Competing Crop, E. Uscanga-Mortera, S. Clay, F. Forcella, J. Gunsolus

Agronomy, Horticulture and Plant Science Faculty Publications

Common waterhemp (Amarathus rudis Sauer) is a frequent weed in glyphosate-resistant (GR) crops in the midwestern USA due, in part, to the delayed emergence of its seedlings. Variable waterhemp emergence was simulated by transplanting seedlings into both corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] and bare plot areas at differing crop growth stages during two growing seasons in western Minnesota. Growth and fecundity were measured. As expected, late planted weeds produced little dry matter and few seeds, and competition from corn or soybean reduced waterhemp dry weight and fecundity by 90% compared with isolated plants. Interestingly, common …


Microarray Analysis Of Late-Season Velvetleaf (Abutilon Theophrasti) Effect On Corn, David P. Horvath, Robert Gulden, Sharon A. Clay Dec 2006

Microarray Analysis Of Late-Season Velvetleaf (Abutilon Theophrasti) Effect On Corn, David P. Horvath, Robert Gulden, Sharon A. Clay

Agronomy, Horticulture and Plant Science Faculty Publications

Microarray analysis was used to identify changes in gene expression in corn leaves collected from plants at the V11–14 growth stage that resulted from competition with velvetleaf. The plants were grown in field plots under adequate N (addition of 220 kg N ha1) and irrigation to minimize N and water stress. Consequently, only differences resulting from competition for micronutrients, light, and perhaps allelopathic stress were anticipated. Genes involved in carbon and nitrogen utilization, photosynthesis, growth and development, oxidative stress, signal transduction, responses to auxin and ethylene, and zinc transport were repressed in corn growing in competition with velvetleaf. …