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Shallow Aggregate Ebb-And-Flow System For Greenhouse Lettuce Production, Joseph Chidiac 2017 University of Arkansas, Fayetteville

Shallow Aggregate Ebb-And-Flow System For Greenhouse Lettuce Production, Joseph Chidiac

Theses and Dissertations

A novel soilless technique for the production of lettuce was developed and evaluated for its viability for ornamental greenhouse growers adapting their ebb-and-flood irrigation benching systems to diversify into growing lettuce, without having to purchase the conventional nutrient film technique (NFT) or deep flow technique (DFT) hydroponic systems. The experimental design was a three by four factorial, with three treatments for aggregate depth (19, 38, and 57 mm) and four treatments for irrigation frequency (once every 1, 2, 4, or 8 hours), for a total of twelve treatment combinations. Each treatment was replicated three times in a randomized complete block ...


The Effect Of Preflood Nitrogen And Flood Establishment Timing On Rice Development, Nitrogen Uptake And Grain Yield, Tyler Richmond 2017 University of Arkansas, Fayetteville

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

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 ...


Living Mulch For Sustainable Maize Stover Biomass Harvest, Cynthia A. Bartel, Chumki Banik, Andrew W. Lenssen, Kenneth J. Moore, David A. Laird, Sotirios V. Archontoulis, Kendall R. Lamkey 2017 Iowa State University

Living Mulch For Sustainable Maize Stover Biomass Harvest, Cynthia A. Bartel, Chumki Banik, Andrew W. Lenssen, Kenneth J. Moore, David A. Laird, Sotirios V. Archontoulis, Kendall R. Lamkey

Kendall R Lamkey

The Renewable Fuels Standard mandate provides enhanced opportunity for maize (Zea mays L.) stover use as a bioenergy feedstock. Living mulch (LM) offers a possible solution for the natural resources constraints associated with maize stover biomass harvest. A two site-year study was conducted near Boone and Kanawha, IA, in both maize following maize (MM) and maize following soybean [Glycine max (L.) Merr.] (SM) sequences to evaluate the impact of established and chemically suppressed Kentucky bluegrass (Poa pratensis L.) (KB) ‘Ridgeline’, ‘Wild Horse’, ‘Oasis’, and ‘Mallard’ blend and creeping red fescue (Festuca rubra L.) (CF) ‘Boreal’ as LM on three maize ...


Evaluating The Impact Of Two Contrasting Tillage Practices On Soil Properties In Central Kentucky, Emily Cook 2017 Murray State University

Evaluating The Impact Of Two Contrasting Tillage Practices On Soil Properties In Central Kentucky, Emily Cook

Posters-at-the-Capitol

Farming practices such as no tillage and plowing can institute change on soil physical and chemical characteristics. In this research, the effects of long-term conventional and no-tillage systems on the selected soil properties were determined in a continuous corn system on a farm with Maury silt loam soil. These samples were taken from University of Kentucky's Research Farm (Spindletop Farm). The field used was tilled in 1969 from bluegrass sod and the first time research was conduced was in 1970. Each plot is 20 ft. by 40 ft. and for many years each plot was split with winter cover ...


A Pectin Methylesterase Zmpme3 Is Expressed In Gametophyte Factor1-S (Ga1-S) Silks And Maps To That Locus In Maize (Zea Mays L.), Adrienne N. Moran Lauter, Michael G. Muszynski, Ryan D. Huffman, M. Paul Scott 2017 U.S. Department of Agriculture

A Pectin Methylesterase Zmpme3 Is Expressed In Gametophyte Factor1-S (Ga1-S) Silks And Maps To That Locus In Maize (Zea Mays L.), Adrienne N. Moran Lauter, Michael G. Muszynski, Ryan D. Huffman, M. Paul Scott

M. Paul Scott

The ga1 locus of maize confers unilateral cross incompatibility, preventing cross pollination between females carrying the incompatible Ga1-s allele and males not carrying a corresponding compatible allele. To characterize this system at the molecular level, we carried out a transcript profiling experiment in which silks from near isogenic lines carrying the Ga1-sand ga1 alleles were compared. While several differentially expressed genes were identified, only one mapped to the known location of ga1. This gene is a pectin methylesterase (PME), which we designated as ZmPme3, and is present and expressed only in Ga1-s genotypes. While a functional ZmPME3 is ...


An End-To-End Convolutional Selective Autoencoder Approach To Soybean Cyst Nematode Eggs Detection, Adedotun Akintayo, Nigel Lee, Vikas Chawla, Mark P. Mullaney, Christopher C. Marett, Asheesh K. Singh, Arti Singh, Gregory L. Tylka, Baskar Ganapathysubramanian, Soumik Sarkar 2017 Iowa State University

An End-To-End Convolutional Selective Autoencoder Approach To Soybean Cyst Nematode Eggs Detection, Adedotun Akintayo, Nigel Lee, Vikas Chawla, Mark P. Mullaney, Christopher C. Marett, Asheesh K. Singh, Arti Singh, Gregory L. Tylka, Baskar Ganapathysubramanian, Soumik Sarkar

Asheesh Singh

Soybean cyst nematodes (SCNs), Heterodera glycines, are unwanted micro-organisms that reduce yields of a major source of food–soybeans. In the United States alone, approximately $1 billion is lost per annum due to cyst nematode infections on soybean plants. Experts have conceived methods of mitigating the losses through phenotyping techniques via SCN eggs density estimation, and then applying the right control measures. Currently, they rely on labor intensive and time-consuming identification of SCN eggs in soil samples processed onto microscopic frames. However, phenotyping a vast array of fields requires automated high-throughput techniques. From an automation perspective, detection of rarely occurring ...


Seed Production In Corn And Soybean, Kendall Lamkey 2017 Iowa State University

Seed Production In Corn And Soybean, Kendall Lamkey

Kendall R Lamkey

Seed production is one of the least visible yet most important aspects of food and feed production. This part of the system is often taken for granted, even by the farmers who plant the seed. One of the reasons is that much of the seed in the United States is provided by the private sector, particularly for corn and soybean. Also, seed production is a technical process that requires in-depth knowledge of the reproductive mechanisms in plants.


Variations In Water And Nutrient Cycling And Soil Properties During Agricultural Landscape Restoration, Heidi Asbjornsen, Matthew J. Helmers, Matthew Z. Liebman, Lisa A. Schulte-Moore, Randall K. Kolka 2017 Iowa State University

Variations In Water And Nutrient Cycling And Soil Properties During Agricultural Landscape Restoration, Heidi Asbjornsen, Matthew J. Helmers, Matthew Z. Liebman, Lisa A. Schulte-Moore, Randall K. Kolka

Matthew J. Helmers

The research team examined differences in nutrient, water and carbon storage and output for selected mixtures of annual and perennial plant communities. The research was set up in 14 small sub-watersheds managed by the U.S. Forest Service as part of the Neal Smith National Wildlife Refuge near Prairie City, Iowa. Each sub-watershed had a different placement of prairie conservation strips within crop fields. The project has continued as part of the "perennializers" working group, also known as the "Science-based Trials of Row Crops Integrated with Prairies" or STRIPs research team.


Surface Waters: Ammonium Is Not Ammonia – Part 3, John E. Sawyer, Matthew J. Helmers 2017 Iowa State University

Surface Waters: Ammonium Is Not Ammonia – Part 3, John E. Sawyer, Matthew J. Helmers

Matthew J. Helmers

Two previous ICM News articles outlined the difference between ammonium and ammonia, the relationship between the two nitrogen forms, and the implication of a combined (ammonium-N plus ammonia-N) analysis related to water quality criteria for aquatic life and chlorination treatment for drinking water.This article focuses on the potential sourcing of ammonium and ammonia in surface waters. Ammonium and ammonia in surface water systems can originate from many sources, and are naturally occurring forms of nitrogen. Predominant sources will vary on a watershed or sub-watershed basis. Also, sources and concentrations are greatly influenced by hydrology, including timing and volume of ...


What Does It Take To Detect A Change In Soil Carbon Stock? A Regional Comparison Of Minimum Detectable Difference And Experiment Duration In The North Central United States, Magdalena Necpálová, Robert P. Anex Jr., Alexandra N. Kravchenko, Lori J. Abendroth, Stephen J. Del Grosso, Warren A. Dick, Matthew J. Helmers, Daryl E. Herzmann, Joseph G. Lauer, Emerson D. Nafziger, John E. Sawyer, Peter C. Scharf, Jeffrey S. Strock, Maria B. Villamil 2017 University of Wisconsin–Madison

What Does It Take To Detect A Change In Soil Carbon Stock? A Regional Comparison Of Minimum Detectable Difference And Experiment Duration In The North Central United States, Magdalena Necpálová, Robert P. Anex Jr., Alexandra N. Kravchenko, Lori J. Abendroth, Stephen J. Del Grosso, Warren A. Dick, Matthew J. Helmers, Daryl E. Herzmann, Joseph G. Lauer, Emerson D. Nafziger, John E. Sawyer, Peter C. Scharf, Jeffrey S. Strock, Maria B. Villamil

Matthew J. Helmers

Variability in soil organic carbon (SOC) results from natural and human processes interacting across time and space, and leads to large variation in the minimum difference in SOC that can be detected with a particular experimental design. Here we report a unique comparison of minimum detectable differences (MDDs) in SOC, and the estimated times required to observe those MDDs across the north central United States, calculated for the two most common SOC experiments: (1) a comparison between two treatments, e.g., moldboard plow (MP) and no-tillage (NT), using a randomized complete block design experiment; and (2) a comparison of changes ...


Soil Moisture Dynamics And Plant Transpiration Under Contrasting Annual-Perennial Cover Types, Matt Helmers, Heidi Asbjornsen, Amy L. Kaleita 2017 Iowa State University

Soil Moisture Dynamics And Plant Transpiration Under Contrasting Annual-Perennial Cover Types, Matt Helmers, Heidi Asbjornsen, Amy L. Kaleita

Matthew J. Helmers

Soil moisture dynamics are influenced by land cover, thus different land covers would be expected to have different soil moisture behavior. This project tested various land covers and crops to see whether and how moisture was retained or depleted.


Impact Of Liquid Swine Manure Application And Cover Crops On Ground Water Quality, Carl H. Pederson, Rameshwar S. Kanwar, Matthew J. Helmers, Antonio P. Mallarino 2017 Iowa State University

Impact Of Liquid Swine Manure Application And Cover Crops On Ground Water Quality, Carl H. Pederson, Rameshwar S. Kanwar, Matthew J. Helmers, Antonio P. Mallarino

Matthew J. Helmers

The primary design of this project was to determine the impact of appropriate rates of swine manure applications to corn and soybeans based on nitrogen and phosphorus requirements on crop yields, soil phosphorus accumulation, and nitrate and phosphorus leaching to groundwater. Another purpose of this design was to develop and recommend appropriate manure and nutrient management practices to producers to minimize the water contamination potential and enhance the use of swine manure as inorganic fertilizer. A third component was to determine the potential effects of rye as a cover crop to reduce nitrate loss to shallow ground water.


Impact Of Drainage Water Management On Crop Yield, Drainage Volume, And Nitrate Loss, Linda Schott, Matt Helmers, Carl Pederson, Greg Brenneman, Myron Rees 2017 Iowa State University

Impact Of Drainage Water Management On Crop Yield, Drainage Volume, And Nitrate Loss, Linda Schott, Matt Helmers, Carl Pederson, Greg Brenneman, Myron Rees

Matthew J. Helmers

The objectives of this study were to determine the impact of shallow, controlled, conventional, and no drainage on crop yields, subsurface drainage volumes, and nitrate loss through subsurface drainage. This research investigates whether drainage water management reduces nitrate loadings to downstream surface waters.


Impact Of 4r Management On Crop Production And Nitrate-Nitrogen Loss In Tile Drainage, Matthew Helmers, John Sawyer, Josh Sievers 2017 Iowa State University

Impact Of 4r Management On Crop Production And Nitrate-Nitrogen Loss In Tile Drainage, Matthew Helmers, John Sawyer, Josh Sievers

Matthew J. Helmers

Corn Belt corn and soybean producers are increasingly challenged to maximize crop production while addressing the contributions farm practices make to Gulf hypoxia. Based on the need for nitrate-N reductions to meet water quality goals, new management practices are needed to reduce nitrate-N losses at minimal cost and maximum economic benefits. This three-year field research and demonstration project is evaluating various promising N management methods and technologies by documenting the nitrate-N export and crop yield from various systems.


Heavy Rain, Soil Erosion And Nutrient Losses, Mahdi Al-Kaisi, Matthew J. Helmers 2017 Iowa State University

Heavy Rain, Soil Erosion And Nutrient Losses, Mahdi Al-Kaisi, Matthew J. Helmers

Matthew J. Helmers

As we write this article spring rains are coming hard and fast causing substantial soil erosion when soils are most vulnerable because of degraded crop residue cover, soil preparation by tillage and no crop canopy. The soil profiles in most of Iowa are now filled to capacity with water. The profiles are at or near saturation. Therefore, the intensity and amount of rain we received have exceeded the soil capacity to filter water and minimize surface runoff even in fields with the most adequate conservation practices.


Investigation Of Bacteria Transport And Resistance Mechanisms And Implications For Water Quality From Confinement Swine And Beef Grazing Production Systems In Iowa, Michelle Soupir, Matt Helmers, Michael L. Thompson, Laura R. Jarboe, Antonio P. Mallarino, Ramesh S. Kanwar 2017 Iowa State University

Investigation Of Bacteria Transport And Resistance Mechanisms And Implications For Water Quality From Confinement Swine And Beef Grazing Production Systems In Iowa, Michelle Soupir, Matt Helmers, Michael L. Thompson, Laura R. Jarboe, Antonio P. Mallarino, Ramesh S. Kanwar

Matthew J. Helmers

This multi-scale, multi-year study was conducted to begin answering questions related to the fate and transport of nutrients and bacteria from land receiving manure application. Experiments were conducted on tile water drainage at an ISU Research Farm in northeast Iowa.


Impact Of Liquid Swine Manure Application And Cover Crops On Nitrate In Subsurface Drainage Water, Carl Pederson, Matt Helmers, Michelle Soupir, Ramesh Kanwar, Antonio Mallarino 2017 Iowa State University

Impact Of Liquid Swine Manure Application And Cover Crops On Nitrate In Subsurface Drainage Water, Carl Pederson, Matt Helmers, Michelle Soupir, Ramesh Kanwar, Antonio Mallarino

Matthew J. Helmers

The primary objective of this project was to determine the impact of appropriate rates of swine manure applications to corn and soybeans based on nitrogen requirements of crops and the potential of nitrate leaching to groundwater. Another purpose of this longterm experimental study was to develop and recommend appropriate manure and nutrient management practices to producers to minimize the water contamination potential and enhance the use of swine manure as an organic fertilizer. A third component of this study was to determine the potential effects of rye as a cover crop to reduce nitrate loss to shallow ground water.


Investigating The Toxicity And Accumulation Of 2,4-Dichlorophenoxyacetic Acid (2,4-D) And Glyphosate In Eisenia Fetida, Caitlin Lazurick, Nicole Lidzbarski, Rachel Owings, Jeff Brotherton, Edna Steele 2017 Converse College

Investigating The Toxicity And Accumulation Of 2,4-Dichlorophenoxyacetic Acid (2,4-D) And Glyphosate In Eisenia Fetida, Caitlin Lazurick, Nicole Lidzbarski, Rachel Owings, Jeff Brotherton, Edna Steele

Journal of the South Carolina Academy of Science

Glyphosate, the main ingredient in Roundup®, is the most widely used herbicide in the world. It is also used in combination with another effective herbicide, 2,4-D, in the formulation called Enlist Duo®. The EPA approved the use of Enlist Duo® on certain crops including those genetically modified to be resistant to both herbicides. The predicted significant increase in the use of these herbicides raised concerns from the general public because both compounds have been classified as possibly or probably carcinogenic. Since herbicides are applied directly to vegetation, the safety of organisms that come in contact with the herbicides is ...


Neonicotinoid Insecticide Removal By Prairie Strips In Row-Cropped Watersheds With Historical Seed Coating Use, Michelle L. Hladik, Steven P. Bradbury, Lisa A. Schulte, Matthew Helmers, Christopher Witte, Dana W. Kolpin, Jessica D. Garrett, Mary Harris 2017 United States Geological Survey

Neonicotinoid Insecticide Removal By Prairie Strips In Row-Cropped Watersheds With Historical Seed Coating Use, Michelle L. Hladik, Steven P. Bradbury, Lisa A. Schulte, Matthew Helmers, Christopher Witte, Dana W. Kolpin, Jessica D. Garrett, Mary Harris

Matthew J. Helmers

Neonicotinoids are a widely used class of insecticides that are commonly applied as seed coatings for agricultural crops. Such neonicotinoid use may pose a risk to non-target insects, including pollinators and natural enemies of crop pests, and ecosystems. This study assessed neonicotinoid residues in groundwater, surface runoff water, soil, and native plants adjacent to corn and soybean crop fields with a history of being planted with neonicotinoid-treated seeds from 2008 to 2013. Data from six sites with the same crop management history, three with and three without in-field prairie strips, were collected in 2015–2016, 2–3 years after neonicotinoid ...


Nitrate Loss In Subsurface Drainage As Affected By Nitrogen Application Rate And Timing Under A Cornsoybean Rotation System, Matthew J. Helmers, Reid D. Christianson, John Sawyer 2017 Iowa State University

Nitrate Loss In Subsurface Drainage As Affected By Nitrogen Application Rate And Timing Under A Cornsoybean Rotation System, Matthew J. Helmers, Reid D. Christianson, John Sawyer

Matthew J. Helmers

Subsurface agricultural drainage has allowed for enhanced crop production in many areas of the world including the upper Midwest, United States. However, the presence of nitrate-nitrogen (nitrate-N) in subsurface tile drainage water is a topic of intense scrutiny due to several water quality issues. Many studies have been conducted looking at ways to reduce nitrate-N in tile drainage (Baker et al., 1975; Baker and Johnson, 1981; Hanway and Laflen, 1974; Kanwar et al., 1988).With the growing concern for the health of the Gulf of Mexico (Mitsch et al., 2001; Rabalais et al., 1996) and local water quality concerns, there ...


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