Project 1. Laboratory analysis of nitrate removal rates in a woodchip bioreactor during nitrate pulse events

Mentor: Dr. François Birgand

Students will work on the concept of 'hot moments' of biogeochemical activity in watersheds. Indeed, following a seminal paper from McClain et al., in 2013, it is now accepted that much of biogeochemical activity in watersheds is concentrated in small areas referred to as 'hot spots', and does not occur uniformly in time. Rather largest activity occurs during short periods of time following rainfall or thawing events, and referred to as 'hot moments'. It turns out that because flow and pollutant loads occur during short periods of time following rainfall events, biogeochemical activities must be disproportionally high during these short times. But this has yet to be shown...! Students will use a replicate of a denitrification hot spot in the landscape (a woodchip bioreactor in the lab) and will measure the large increase of denitrification rates during pulses of nitrate loads, using state of the art high frequency water quality sensors. Students will physically manipulate inlet flow and concentrations, and will analyze high frequency nitrate sensor and flow data to eventually calculate volumetric removal rates. Students will use the reproducible research platform offered by R and RMarkdown software to conduct and report their analyses.

Project 2. Investigating Drainage Districts Formation and Management in North Carolina

Mentor: Dr. Andrew Branan 

The North Carolina Drainage Act of 1909 established a process by which landowners or groups of landowners could establish agricultural drainage systems on theirs and neighboring parcels. These drainage systems - known as Drainage Districts - exist throughout the coastal plain of eastern North Carolina. Though functioning, they are little understood by policy makers, and have been identified as possible conduits for nutrient pollution and possibly salt-water intrusion. The scope of this project will be to pull together publicly available information on drainage district formation - including interpretation of the Act and any applicable administrative rules. Also, conduct a limited survey of district administrators to collect data on maintenance costs and landowners assessments, as well as status of access rights for maintenance. The project is an important component of needed research into these systems to assist policy makers in evaluating improvements and future utility of the system for agricultural drainage and coastal resiliency. 

Project 3. Evaluating novel, low cost and environmentally friendly technology for nitrogen and phosphorus removal
Mentor: Dr. Mike Burchell

This project will evaluate novel low cost and environmentally friendly technologies that combine physical and biological processes to enhance N and P removal and

recovery at smaller rural wastewater treatment facilities. This project builds off our previous work focused on constructed wetlands at a NC town which resulted in measurable improvements in nitrogen treatment. This project will evaluate the N and P removal potential of a combination of wastewater treatment alternatives that will include a blend the use of small-scale constructed wetlands with specially produced biochar (a processed waste wood material). Students will contribute to this project by conducting both laboratory and field studies to evaluate combinations formulations ideal for N and P removal, and participate in field data collection from a full scale constructed wetlands treating wastewater.

Project 4. Effect of Application History and Edaphic Factors on Pesticide Persistence and Efficacy

Mentor: Dr. Travis Gannon

Residual herbicides are commonly applied to agronomic systems to control many annual weed species. Oxadiazon is a pre-emergent herbicide that inhibits growth of emerging annual grasses and broadleaves that provides weed control without detrimentally affecting the health of many warm-season turfgrass species and is commonly used on golf courses and other use sites. Prodiamine is a pre-emergent herbicide that inhibits growth of emerging annual grasses and broadleaves and is highly efficacious herbicide used on golf courses and many other cool- and warm-season turfgrass systems. For effective weed control, it is critical for oxadiazon or prodiamine to persist through critical weed emergence periods in the soil from when it is applied to the time of weed seed germination at a lethal concentration. Soil properties including organic matter content, environmental conditions, such as moisture, and herbicide physicochemical properties, have been described as factors that influence persistence and efficacy of preemergent herbicides such as oxadiazon (and other PPO herbicides) as well as prodiamine (and other dinitroaniline herbicides). In recent years, a decline in oxadiazon and prodiamine efficacy has been observed and managers have increased application rates to attempt to mitigate the issue; however, there is a vital need to characterize degradation processes that affect oxadiazon and prodiamine persistence and efficacy to identify solutions or mitigation strategies. The objectives of the project are to conduct laboratory analyses to:

1. Elucidate differences in preemergent herbicide (oxadiazon and prodiamine) degradation rates in soils with varying length of use

2. Investigate the influence of edaphic factors on preemergent herbicide degradation.

Project 6. A large scale survey of manure sourcing and use in North Carolina

Mentor: Dr. Stephanie Kulesza 

The intern in the Animal Waste Management Lab will be joining a cohort of other interns in conducting widespread surveys of poultry and swine producers, row crop farmers, third party manure haulers and exporters, manure energy companies, and manure clean out service providers to understand how manure is sourced and used in North Carolina. We are hoping to develop a manure marketplace that could help with redistribution of manures to better utilize these nutrients. However, we need to fully understand the market as it exists today before we move forward with development of a centralized marketplace.