Submitted to: Earth Surface Processes and Landforms
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/16/2009
Publication Date: 6/12/2009
Citation: Sharratt, B.S., Feng, G. 2009. Windblown dust influenced by conventional and undercutter tillage within the Columbia Plateau, USA. Earth Surface Processes and Landforms. 34, 1323–1332.
Interpretive Summary: Dust emissions resulting from high winds during the summer fallow phase of a wheat/fallow rotation contribute to poor air quality within the Columbia Plateau region of the Pacific Northwest. Undercutter tillage has been promoted as a conservation tillage practice to reduce windblown dust emissions during summer fallow, but no comparisons of dust emissions have previously been made between undercutter tillage and conventional tillage. Dust emissions were measured from conventional and undercutter tillage during high winds in eastern Washington. Windblown dust emissions from undercutter tillage were 15 to 65% lower than from conventional tillage. Undercutter tillage appears to be an effective conservation tillage tool that can be used by growers for reducing windblown dust emissions from agricultural soils and by the USDA-NRCS in conservation planning.
Technical Abstract: Exceedance of the US Environmental Protection Agency national ambient air quality standard for PM10 (particulate matter 10µm or smaller in diameter) within the Columbia Plateau region of the Pacific Northwest US is largely caused by wind erosion of agricultural lands managed in a winter wheat – summer fallow rotation. Land management practices, therefore, are sought that will reduce erosion and PM10 emissions during the summer fallow phase of the rotation. Horizontal soil flux and PM10 concentrations above adjacent field plots (>2 ha), with plots subject to conventional or undercutter tillage during summer fallow, were measured using creep and BSNE sediment collectors and PM10 samplers installed at various heights above the soil surface. After wheat harvest in 2004 and 2005, the plots were either disked (conventional) or undercut with wide sweeps (undercutter) the following spring and then periodically rodweeded prior to sowing wheat in late summer. High winds conducive to assessing erosion during the fallow phase occurred during six sampling periods in two years, but erosion or PM10 loss was not observed during two sampling periods due to the presence of a crust on the soil surface. For the remaining sampling periods, soil loss from conventional and undercutter tillage ranged from 3 to 40 g m-2 and 1 to 27 g m-2 while PM10 loss from conventional and undercutter tillage ranged from 0.2 to 5.0 g m-2 and 0.1 to 3.3 g m-2, respectively. Undercutter tillage resulted in a 15 to 65% reduction in soil loss and 30 to 70% reduction in PM10 loss as compared with conventional tillage. Undercutter tillage, therefore, appears to be an effective management practice to reduce dust emissions from agricultural land subject to a winter wheat – summer fallow rotation within the Columbia Plateau.