Soil Wind Erosion on Agricultural Field and Its Impact on Air Quality: Measurement and Modelling.
Guanglong Feng, Washington State Univ, Biol. Sys. Engineering Dept, Pullman, WA 99164-6120 and Brenton Sharratt, USDA-ARS, 213 LJ Smith Hall, Pullman, WA 99164-6120.
Wind-induced soil erosion threatens soil productivity and air quality throughout the world. It has long been a serious problem in the inland Pacific Northwest (PNW), soil erosion associated with conventional farming practices results in soil degradation and threatens agriculture sustainability. Particulates less than 10 Ám in diameter (PM10) that erode from agricultural soils contribute to poor quality. Exposure to high level of PM10 can cause serious health problems. Few conservation tillage systems are available to growers for controlling erosion. It is not clear whether soil loss and dust emission can be reduced by these tillage practices. On-farm documentation is needed for recommending an undercut tillage practice. The Wind Erosion Prediction System (WEPS) was developed for predicting soil loss and dust emission from agricultural land. Therefore, it was applied to this region and its performances were evaluated. The objectives were to measure soil loss and PM10 emission from agricultural fields and evaluate the effectiveness of an undercut tillage system in controlling erosion, using both monitoring and modelling techniques. Instruments were installed at three positions on each site of three farms in eastern Washington during 2003-2005 to measure the loss of soil (using BSNE and Creep airborne sediment samplers) and PM10 (using high volume air samplers and E-samplers) from a wheat field and two fallow fields under conventional and conservational tillage systems. A dust storm on October 28, 2003 obscured visibility throughout the region and resulted in a 40-car accident near Prosser, Washington. The high wind event resulted in a loss of topsoil greater than 1200 kg ha-1 and a loss of PM10 of 220 kg ha-1 from the field site. The soil loss and dust emission under two tillage systems on another farm will be compared and reported. The results of application and evaluation of WEPS in the region will be presented.