Mapping key agricultural sources of dust emissions within the Lake Simcoe airshed

Abstract

A decline in water quality attributed to excessive inputs of phosphorus has been observed in Lake Simcoe over the past few decades. Various studies have estimated that 25–50% of the total phosphorus entering the lake is from atmospheric deposition. Bare soil exposure in the spring due to lack of vegetative cover, along with soil disturbance related to agricultural activities, results in higher susceptibility to wind erosion and dust emission. This study introduces the new concept of Dust Response Units (DRUs), which combine soil type and land use to determine the dust emission susceptibility based on the hourly variation of wind speed and monthly changes in soil cover due to crop growth. The Wind Erosion Prediction System (WEPS) was used to determine dust emission suppression factors for a combination of 11 different soils and 6 dominant agricultural land uses, totaling 66 different DRUs in the Lake Simcoe airshed. Employing a widely used dust emission model and applying these dust emission suppression factors resulted in the identification of high risk DRUs. Twelve of the potential 66 DRUs were determined to contribute 85% of the total crop dust emissions within the Lake Simcoe airshed, including sand, loam, sandy loam, and loamy sand soils combined with row crop, mixed, and hay and pasture land management operations. This study demonstrates a new method to map high priority areas for targeted implementation of dust control best management practices that could be useful in agricultural areas both within and beyond the Lake Simcoe airshed