PM10 emission from feedlots in soils with different texture: Cattle trampling effect

Abstract

Cattle feedlot surfaces can be an important aerosol source, but they have barely been studied. The action of the hooves on the loose, dry layer of soil and manure creates ideal conditions for particulate matter (PM) emissions. The objectives of this work were: a) to quantify the soil loss (Q) and the consequent emission of PM10 (FvPM10) from different surfaces within the feedlot: unpaved roads (UR), cropland (C) and cattle pen (CP); and b) to evaluate the cattle trampling effect in UR, C and CP on Q and FvPM10. The study was carried out in three feedlots with different soil textures: Trenel (FT), Santa Rosa (FSR) and General Acha (FGA). In a wind tunnel, erosion events were simulated at 10.5 m s−1 (µ*: 0.26 m s−1) during 5 min. The results showed that Q and FvPM10 were UR > C > CP and that the cattle trampling effect was generally directly proportional to Q and FvPM10 (p < 0.05). In general the emission efficiency (calculated as FvPM10/Q) was higher in the feedlot with the finest soil texture (FT) than in the other two feedlots with coarser soil (FSR and FGA). Regarding the type of surface, emission efficiency from UR was lower than from C and CP surfaces. CP presented the lowest values of Q and FvPM10, but it showed high RE so it could be considered a continuous source of wind derived emission of PM10 due to the effect of permanent trampling.