Nutrient Sufficiency Ranges for Corn at the Early Growth Stage: Implications for Nutrient Management.

Growers rely on nutrient sufficiency ranges (NSRs) after plant tissue analysis to inform timely nutrient management decisions. The NSRs are typically established from survey studies across multiple locations, which could be confounded by several abiotic and biotic factors. We conducted field studies in 2020, 2021, and 2022 to validate the lower thresholds of the NSRs for corn () at the early growth stage as reported in the Southern Cooperative Series Bulletin #394.

Evaluating the impact of turf-care products on soil biological health.

Golf courses require extensive use of inputs to meet the needs of playability and aesthetics. The impact of these inputs on soil biological health is largely unknown. Two field trials were conducted at a golf course in Georgia to evaluate short-term effects of wetting agents (Cascade Plus and Duplex [C+D], Revolution [Rev]), plant growth regulators (PrimoMaxx [PM] and Cutless [CL]), and a product called PlantHelper (PH) on soil biological health by measuring microbial abundance and function.

Inactivation of Escherichia coli O157:H7 and Salmonella during washing of contaminated gloves in levulinic acid and sodium dodecyl sulfate solutions.

Field workers often wear gloves harvesting ready-to-eat produce; however, fields are not sterile environments and gloves may become contaminated numerous times during a working shift. This study explored the potential for inactivation of Escherichia coli O157:H7 and Salmonella when contaminated gloves were washed in levulinic acid (LV) and sodium dodecyl sulfate (SDS) solutions. Washing nitrile gloves with increasing concentrations of LV above 1.

Inactivation of Escherichia coli O157:H7 and Salmonella deposited on gloves in a liquid state and subjected to drying conditions.

Gloves are worn by workers harvesting ready-to-eat produce as a deterrent for contaminating the produce with enteric pathogens that may reside on their hands. As fields are not sterile environments, the probability for gloves to become contaminated still exists and therefore it is critical to understand the conditions that affect the survival of pathogens on gloves. Both Escherichia coli O157:H7 and Salmonella deposited on glove surfaces in a liquid state survived longer when the pathogen had been suspended in lettuce sap than when suspended in water.

Subcellular distribution and biotransformation of phenanthrene in pakchoi after inoculation with endophytic Pseudomonas sp. as probed using HRMS coupled with isotope-labeling.

Contamination of food-crops with polycyclic aromatic hydrocarbons (PAHs) poses a grave concern to food safety, especially when PAHs are internalized. We have demonstrated in our previous study that inoculation of crop with a phenanthrene-degrading endophytic Pseudomonas sp. Ph6-gfp could overcome this problem.

Ammonia Oxidizers in a Grazing Land with a History of Poultry Litter Application.

Poultry litter (PL) is widely applied on grazing lands in Georgia. However, it is not clear how its long-term use affects soil microorganisms and their function. We examined changes in activity and community structure of ammonia-oxidizing archaea (AOA) and bacteria (AOB) in a grazing land with a history of PL application and compared it to treatment with urea ammonium nitrate (UAN).

Modeling the Effects of Onsite Wastewater Treatment Systems on Nitrate Loads Using SWAT in an Urban Watershed of Metropolitan Atlanta.

Onsite wastewater treatment systems (OWTSs) can be a source of nitrogen (N) pollution in both surface and ground waters. In metropolitan Atlanta, GA, >26% of homes are on OWTSs. In a previous article, we used the Soil Water Assessment Tool to model the effect of OWTSs on stream flow in the Big Haynes Creek Watershed in metropolitan Atlanta.

Isolating the impact of septic systems on fecal pollution in streams of suburban watersheds in Georgia, United States.

The presence of multiple sources of fecal pollution at the watershed level presents challenges to efforts aimed at identifying the influence of septic systems. In this study multiple approaches including targeted sampling and monitoring of host-specific Bacteroidales markers were used to identify the impact of septic systems on microbial water quality. Twenty four watersheds with septic density ranging from 8 to 373 septic units/km were monitored for water quality under baseflow conditions over a 3-year period.

Confirmation of the Impact of Onsite Wastewater Treatment Systems on Stream Base-Flow Nitrogen Concentrations in Urban Watersheds of Metropolitan Atlanta, GA.

Wastewater and lawn fertilizer potentially contribute to degraded water quality in urban watersheds. Previously we described a study from 2011 to 2012 in which we examined the effect of the density of onsite wastewater treatment systems (OWTS) on nitrogen concentrations in 24 small streams in metropolitan Atlanta. Our objective in this study was to confirm that the impact on water quality that we observed was due to OWTS and not lawn fertilizer.

Ammonia-oxidizer communities in an agricultural soil treated with contrasting nitrogen sources.

The community of ammonia-oxidizing prokaryotes was examined in an agricultural soil treated for six seasons with contrasting nitrogen (N) sources. Molecular tools based on the genes encoding ammonia monooxygenase were used to characterize the ammonia oxidizer (AO) communities and their abundance. Soil DNA was extracted from soils sampled from silage corn plots that received no additional N (control), dairy waste compost, liquid dairy waste (LW), and ammonium sulfate (AS) treatments at approximately 100 and 200 kg available N ha(-1) over 6 years.

Prevalence and concentration of Salmonella and Campylobacter in the processing environment of small-scale pastured broiler farms.

A growing niche in the locally grown food movement is the small-scale production of broiler chickens using the pasture-raised poultry production model. Limited research exists that focuses on Salmonella and Campylobacter contamination in the environment associated with on-farm processing of pasture-raised broilers. The objective of this study was to establish data relative to Salmonella and Campylobacter prevalence and concentration in soil and mortality compost resulting from prior processing waste disposal in the small-scale, on-farm broiler processing environment.

Degradation of multiwall carbon nanotubes by bacteria.

Understanding the environmental transformation of multiwall carbon nanotubes (MWCNTs) is important to their life cycle assessment and potential environmental impacts. We report that a bacterial community is capable of degrading (14)C-labeled MWCNTs into (14)CO2 in the presence of an external carbon source via co-metabolism. Multiple intermediate products were detected, and genotypic characterization revealed three possible microbial degraders: Burkholderia kururiensis, Delftia acidovorans, and Stenotrophomonas maltophilia.

Leaching of Mycobacterium avium Subsp paratuberculosis in Soil under In Vitro Conditions.

Mycobacterium avium subsp paratuberculosis (Map), the causative agent of Johne's disease, has a robust ability to survive in the environment. However, the ability of Map to migrate through soil to drainage tiles or ground water, leave the farm, and leak into local watersheds is inadequately documented. In order to assess the ability of Map to leach through soil, two laboratory experiments were conducted.

Understanding the role of agricultural practices in the potential colonization and contamination by Escherichia coli in the rhizospheres of fresh produce.

To better protect consumers from exposure to produce contaminated with Escherichia coli, the potential transfer of E. coli from manure or irrigation water to plants must be better understood. We used E.

Nitrification exhibits Haldane kinetics in an agricultural soil treated with ammonium sulfate or dairy-waste compost.

An agricultural soil was treated with dairy-waste compost, ammonium-sulfate fertilizer or no added nitrogen (control) and planted to silage corn for 6 years. The kinetics of nitrification were determined in laboratory-shaken slurry assays with a range of substrate concentrations (0-20 mM NH(4)(+)) over a 24-h period for soils from the three treatments. Determined concentrations of substrate and product were fit to Michaelis-Menten and Haldane models.