Fate and transport of colloidal-facilitated nutrients and heavy metals via preferential flow pathways
Over-application of animal manure on agricultural lands can result in nutrient and heavy metals enrichment of subsurface effluent when conditions promote contaminant leaching such as preferential flow through soil macropores. In this research project, we are quantifying the soil macropore characteristics using X-Ray Computed Tomography (CT) imaging and linking this information with column leaching experiments and water and solute transport modeling (HYDRUS-1D). The results of this research will help in evaluating water and nutrient movement in agricultural soils (pastures, row crops) and soil tillage practices (no-till and tilled) and aid in developing best management practices (BMPs) aimed at mitigating nutrient loss from agricultural landscapes while maintaining adequate nutrient levels for plant growth.
Sediment Fingerprinting for in-stream sediment source
identification
Increase in urbanization results in alteration of hydrological and sedimentological processes, posing a risk to aquatic ecosystems such as streams and lakes. The augmented supply of sediment to the channel can lead to degradation of water quality and reduced biodiversity. Therefore, identification of the dominant source of in-stream sediment in a watershed can help design cost-effective sediment management strategies that will achieve meaningful reductions in sediment load and mitigate the negative impacts of sediment and sediment-associated contaminants on water quality. For my Master's research at Auburn University, I used a sediment fingerprinting technique in conjunction with watershed-scale modeling to better understand sediment movement processes from uplands and stream banks (sources) to receiving waters (point of impact). I used a combination of statistical analysis, machine learning, Bayesian statistics, and Soil and Water Assessment Tool (SWAT) to identify and apportion sediment sources of suspended and stream bed sediment (NPS pollutant) in an urban watershed. The study's results showed that the construction sites and stream banks were important sources of in-stream sediment.
Impact of biochar on nutrient losses in runoff from soil amended with poultry litter
Agricultural runoff from fields amended with poultry litter contains several contaminants, such as nutrients, which can end up in waterways and cause harmful algal blooms and other environmental problems. A wide variety of best management practices have been used to reduce the impact of agricultural practices on water quality. In one such project, I worked together with an M.S. student to examine how the biochar addition, at varying levels, can affect the concentrations of phosphorus, nitrogen, and total organic carbon in the runoff from plots amended with poultry litter.