Assessing Herbicide and Fertilizer Drift between Conventional and Organic Farmland | AIChE

Assessing Herbicide and Fertilizer Drift between Conventional and Organic Farmland

The Spring Valley Student Farm (SVSF) and EcoGarden are two student farms at the University of Connecticut (UConn) that are operated under organic farming procedures. Adjacent are conventional farmlands that utilize synthetic herbicides and fertilizers on their crops. The objective of this study was to determine if any reasonable herbicide or fertilizer drift amassed on the organic farmland which might counteract their organic practices. Over the course of eleven weeks air and rainfall samples were collected on the SVSF and to a lesser extent EcoGarden. The approach used a combination of monitoring methods including low cost particulate matter (PM) sensors (AlphaSense OPC-N2), low-volume particulate pump monitors (3000 cm3/min) with separate herbicide and fertilizer filters, passive rainfall collectors, and a weather station (Ambient Weather WS-1001-WIFI). These methods allowed monitoring of both dry and wet deposition onto the farmland. Eleven weeks of samples were collected and analyzed between May and August of 2017. Analysis of herbicides focused on three major brands (via their main active ingredient) being utilized: Makaze (glyphosate), Crossbow (2,4-dichlorophenoxyacetic acid), and Strut (Diglycolamine salt of 3,6-dichloro-Q-anisic acid). Analysis of total PM nitrogen from the low-volume air samplers and the rainfall samples served as a proxy for fertilizer application. PM monitors were analyzed via MatLab and compared with weather conditions to determine the relationship between total PM and drift. The air filters and water samples were analyzed by UConn’s Center for Environmental Science and Engineering (CESE). Major applications of herbicides occurred on June 29th and 30th utilizing a boom sprayer while fertilizer application occurred much more frequently. Initial results indicate that herbicide drift via wet deposition was recorded at a higher rate at EcoGarden likely due to a lack of tree buffer. Drift via dry deposition was nearly negligible at the SVSF. Several hits were recorded before the first spray event indicating some sort of alternative source of herbicides is nearby to the SVSF and EcoGarden.