Submitted to: International Symposium on Soil Erosion and Dryland Farming
Publication Type: Proceedings
Publication Acceptance Date: 10/5/2006
Publication Date: 10/5/2006
Citation: Sharratt, B.S., Wendling, L., Feng, G. 2006. Undercutter Method of Tillage for Reducing Wind Erosion and Dust Emissions in Eastern Washington. International Symposium on Soil Erosion and Dryland Farming.
Technical Abstract: Wheat growers in the low precipitation zone (<300 mm annual precipitation) of eastern Washington in the Pacific Northwest United States produce a crop every other year. In non crop years, growers maintain their land in summer fallow to control weeds and conserve soil water for the succeeding winter wheat crop. Summer fallow traditionally includes sweeping after harvest in late summer, chiseling in autumn, cultivating the following spring, and then rod weeding throughout the summer. Summer fallow is very susceptible to wind erosion which contributes to poor air quality across the region. In fact, several locations in eastern Washington have failed to meet the US EPA national ambient air quality standard for PM10 (particulates less than 10 micrometers) due to elevated dust concentrations as a result of wind erosion. Few if any alternatives to traditional tillage have been identified that are sustainable in a wheat-fallow rotation. The objective of this study was to compare dust emissions during a simulated high wind event following various postharvest tillage operations. Treatments were established on a silt loam after harvest of winter wheat in August 2004 and included traditional, undercutter, and no tillage. Undercutter tillage included making a pass with an undercutter (an implement with 80 cm wide V-blades) in spring followed by rod weeding during the summer. A portable wind tunnel was used to assess dust emissions. Sediment flux and PM10 concentrations at various heights above the soil surface were measured within the working section of the wind tunnel. Dust emissions at the end of summer fallow (August 2005) were lowest for no tillage and highest for traditional tillage. The undercutter method of tillage reduced emissions by nearly 50% as compared with traditional tillage. This study suggests that less intensive tillage in autumn and spring will reduce dust emissions from silt loams within the wheat-fallow region of eastern Washington.