Digital Commons Network^™

Evaluation Of Microbiometer As A Tool To Estimate Soil Health In A West Tennessee Cotton Crop, Daniel T. Sain

Masters Theses

Healthy soils are critical for optimized yields and sustainability in agriculture. Soil health testing can provide valuable information on how management practices are affecting soil health. In west Tennessee, existing soil health tests were unable to discern between significant differences in management practices. A new soil health test called microBIOMETER® has been developed by Prolific Earth Sciences® (Montgomery, NY). MicroBIOMETER® utilizes a new methodology for estimating microbial biomass and uses that estimate as a soil health score. This test has not been validated for use in west Tennessee. This research was focused on the validation of microBIOMETER® in a continuous …

Evaluation Of Insecticide Resistance In Populations Of Tobacco Thrips, Frankliniella Fusca (Hinds), And Plant Density Effects On Thrips Injury To Cotton, Jessica L. Krob

Masters Theses

Two field studies were performed in Tennessee to evaluate the effects of plant density and seed spacing on thrips injury to upland cotton (Gossypium hirsutum L.). The plant density study consisted of seeding rate treatments that were low, normal, high, and very high, relative to university Extension recommendations. In the plant spacing study, treatments were implemented using nearly identical seeding rates but with relatively uniform seed spacing versus a clumped, “hill-dropped” spacing. In both studies, the seed was either treated with an insecticide (imidacloprid) and a fungicide or only with a fungicide. Due to variable environmental conditions, the results …

Improving Water And Plant Growth Regulator (Pgr) Management Practices In Cotton: Cultivar Physiological Responses And Pgr Rates, Kurt Wedegaertner

Masters Theses

Cotton (Gossypium hirsutum L.) is grown in an increasingly unpredictable climate and often under rainfed conditions. Without irrigation to alleviate common drought conditions, cultivar selection becomes a primary tool in mitigating the negative effects of water-deficit stress. Cultivars can differ in water use under water-limited environments, which can affect crop performance. Moreover, cotton management must involve balancing vegetative and reproductive growth through the use of plant growth regulators (PGR) due to the plant’s perennial growth pattern. The efficacy of PGRs are dependent on many variables including environmental conditions, irrigation, and genetics (cultivar). In 2020 and 2021, a series of …

Risk Management Potential Of Supplemental Irrigation For Cotton In A Sub-Humid Climate Under Climate Change, Wen Liu

Masters Theses

Adoption of supplemental irrigation to reduce cotton yield losses is a potential risk management strategy for farmers given increasingly frequent drought periods due to climate change. However, cotton farmers in the rolling landscape areas of the lower Mississippi River Basin (MRB) are concerned about whether an investment in supplemental irrigation is economically feasible. This study determined the impacts of the effects of risk exposure on optimal irrigation strategies for cotton production under climate change in West Tennessee. A crop simulation model was calibrated and validated using measured data from cotton irrigation experiments at Jackson, TN over three years (2006–2008). Simulated …

Helicoverpa Zea (Boddie) (Lepidoptera: Noctuidae) Larval Distribution On Different Bt Technologies And Evaluating Cotton Plant Tissue Assays For Resistance Monitoring, Dawson David Kerns

Masters Theses

Field trials were conducted in 2018 at the West Tennessee Research and Education Center (WTREC) in Jackson, TN and in 2019 at locations in College Station, TX, Tillar, AR, and Jackson, TN. Non-Bt, Cry1Ac + Cry1F, and Cry1Ac + Cry2Ab cotton varieties were either treated with an insecticide or left untreated. After five days, cotton plants were mapped for signs of bollworm, Helicoverpa zea (Lepidoptera: Noctuidae), feeding on floral structures (i.e., bolls, squares, flowers) and the physical presence of larvae. Bt technologies reduced the number of H. zea larvae and the amount of feeding injury, but no major differences in …

Analyzing Populations Of Cotton Seedling Disease And Evaluating Seed Treatment Efficacy, Shelly Pate

Masters Theses

In an effort to provide Tennessee cotton growers, and cotton growers across the South Eastern portion of the cotton belt, with more accurate pathogen identification for soilborne diseases known to cause cotton seedling diseases, I will be working in conjunction with the National Cottonseed Treatment program to analyze populations of cotton seedling disease and evaluate seed treatment efficacy. Over the past 24 years, the National Cottonseed Treatment program has been conducted with the purpose of analyzing populations of soil borne pathogens known to cause cotton seedling diseases across the United States cotton belt. However, this data has only been collected …

Potential Interaction Between Pre- And Post-Emergence Herbicides And The Efficacy Of Insecticide And Fungicide Seed Treatments In Cotton, Cory Joseph Vineyard

Masters Theses

An apparent reduction in the performance of neonicotinoid seed treatments in controlling thrips, especially in cotton, has been observed, which has coincided with the increased use of both pre- and post-emergence herbicides to control glyphosate-resistant weeds. The objective of this research was to evaluate the potential interactions of both pre- and post-emergence herbicides on the efficacy of insecticide and fungicide seed treatments in cotton

Aldicarb along with imidacloprid and thiamethoxam seed treatments reduced thrips numbers compared with non-treated seed. However, thiamethoxam did not provide effective control. Some pre-emergence herbicide treatments reduced plant health. While there was evidence that thrips injury …

Long-Term Impacts Of Conservation Management Practices On Soil Carbon Storage, Stability, And Utilization Under Cotton Production In West Tennessee, Candace Brooke Wilson

Masters Theses

Biogeochemical cycling of soil carbon (C) is heavily influenced by conservation agricultural (CA) practices. This study examined SOC stability under three CA practices: reduced nitrogen (N) fertilizer application rate, cover cropping, and zero-tillage implemented for 31 years. Respiration rates measured from a 602-day incubation period were fitted to a double-pool first order exponential model of SOC decomposition. The active [respired] SOC pool showed distinct differences between applications of reduced (34N kg ha^-1 [-1]) and high fertilization rates (101N kg ha^-1) combined with tillage, and suggest that high fertilizer applications with conventional tillage allocated more C into a …

Effects Of Optical Sensing And Variable Rate Technology On Nitrogen Fertilizer Use, Lint Yields, And Profitability In Cotton Production, Melissa Reynolds Stefanini

Masters Theses

Nitrogen (N) fertilizer is expensive and can be harmful to the environment. Precision agriculture (PA) has the capability to reduce the amount of excess N from crop production released into the environment, increase net returns to the grower, and reduce the risk of profit loss due to spatial and temporal variability. The objectives of this study were to evaluate the profitability, risk management potential, and N use efficiency of using real-time optical sensing with variable-rate technologies (VRT) to manage spatial variability in cotton production. Data collected from 29 field trials in Tennessee, Louisiana, Mississippi, and Missouri from 2011 to 2014 …

An Examination Of Fertilizer Use Efficiency And Irrigation Management In Tennessee Agricultural Production, Timothy James Grant

Masters Theses

Understanding the effect of supplemental irrigation and timing of nitrogen availability on yield of cotton is pertinent to the success of Tennessee cotton producers. Response to irrigation and nitrogen source is likely to vary across greatly differing soil types. This research indicated the need for higher amounts of water and earlier irrigation initiation to optimize yields in coarse-textured, low water holding capacity soils. Deep silt loam soils did not respond to irrigation in two wet years. Delaying nitrogen availability via use of a polymer coated urea fertilizer generally either lowered or did not affect yield. Delaying nitrogen availability was less …

Locating The Variability Of Soil Water Holding Capacity And Understanding Its Effects On Deficit Irrigation And Cotton Lint Yield, Heath Adam Duncan

Masters Theses

Precision irrigation equipment such as variable-rate center pivots is readily available to Tennessee growers and producers; however, little research exists describing its application to cotton grown in Tennessee. In order to optimize the use of variable-rate irrigation equipment and water resources, two experiments were performed to determine (1) whether or not ground-penetrating radar (GPR) and electrical conductivity (EC) measurements can be used to delineate variable-rate irrigation zones and (2) examine the response of cotton lint yield to varying rates and duration of irrigation.

GPR and EC measurements were recorded, validated using soil cores, and used to identify the subsurface variability …

Two Studies Evaluating Input Use In Soybean And Cotton Production, Nathanael Mark Thompson

Masters Theses

Farmers are price takers for both inputs and outputs. Therefore, when the prices of inputs rise, as they have with many inputs used in agricultural production, optimal production practices may change. Two separate studies of the impacts of agricultural technology on input use in crop production were undertaken in this thesis. The first study evaluated economically optimal plant population considering seeding rate, maturity group, row spacing, and input-output prices in soybean production in the rolling uplands region of the upper Midsouthern United States. Data from field experiments at the University of Tennessee Research and Education Center at Milan, Tennessee during …

Cotton (Gossipium Hirsutum L.) Response To Irrigation And Environment In A Short Season Climate, Matthew Scott Wiggins

Masters Theses

Research was conducted in 2010 and 2011 at the West Tennessee Research and Education Center in Jackson, TN to investigate water deficit and irrigation response in cotton to provide a better understanding of physiological growth changes and yield impact on the crop grown in soils of varying depth to a sandy layer. The deep soil yielded more vegetative mass when compared with the shallower soil. This is also true when applying higher rates of irrigation where plants grew two more nodes of growth and 15.2 centimeters of plant height. Time to cotton maturity was delayed seven days in the deep …

Soil Test Information In Cotton Production: Adoption, Use, And Value In Potassium Management, David Caldwell Harper

Masters Theses

Soil sampling can help producers gain more accurate knowledge about soil nutrient properties and field-level characteristics. This information aids in the placement and timing of fertilizer application. Optimal input application may lower variable costs, increase economic returns, and moderate off-site environmental impacts of farming. Yet producer decisions to incorporate soil information into management practices and perceptions about the value of soil test information over time depends on a wide range of economic, social, and producer characteristics. Studies examining the value of soil information for optimal nutrient management may help inform producers considering adopting these technologies about the potential benefits of …

Evaluation Of Spring And Fall Burndown Application Timings On Control Of Glyphosate-Resistant Horesweed In No-Till Cotton, Lucas Neil Owen

Masters Theses

Field studies were conducted in 2007 and 2008 to evaluate fall applications of herbicides to control GR horseweed prior to planting cotton. Fall treatments were compared with spring treatments for control of GR horseweed and effect on seed cotton yield. Fall and spring treatments with and without residual herbicides were also compared. No differences were observed for control of GR horseweed or seed cotton yield for both fall and spring application timings. However, a difference was observed between fall applications with and without a residual herbicide. Fall applications that contained residual herbicides provided 86% control of GR horseweed and yielded …