Windblown Dust Potential from Oilseed Cropping Systems in the Pacific Northwest United States

Abstract

The volatility of petroleum reserves and prices coupled with concerns about greenhouse gas emissions and climate change has created worldwide interest in renewable fuels. Little is known, however, about the impact on natural resources of growing oilseed crops for biofuel. This study examined the impact of growing oilseed crops in winter wheat (Triticum aestivum L.) rotations on wind erosion and emissions of particles ≤10 μm in aerodynamic diameter (PM10) in eastern Washington, where atmospheric PM10 is an acute environmental concern. Wind erosion and PM10 emissions were measured immediately after sowing winter wheat in a winter wheat–summer fallow (WW‐SF) rotation, a winter wheat–camelina [Camelina sativa (L.) Crantz]–summer fallow (WW‐C‐SF) rotation, and a winter wheat–safflower (Carthamus tinctorius L.)–summer fallow (WW‐S‐SF) rotation. Best management practices were implemented during the 13‐mo fallow phase of the rotation, which included undercutting and fertilizing the soil in spring and rodweeding during summer to control weeds. A wind tunnel was used to assess horizontal sediment and PM10 flux after sowing wheat because this is the time when the soil is most susceptible to wind erosion. Horizontal sediment and PM10 flux were as much as 250% higher after sowing winter wheat in the WW‐C‐SF and WW‐S‐SF rotations than the WW‐SF rotation. Vertical PM10 flux was higher in the WW‐C‐SF and WW‐S‐SF rotations, in part due to the aerodynamically smoother surface of these rotations compared with the WW‐SF rotation. Farmers must be especially judicious in protecting the soil from wind erosion during the fallow phase of the WW‐C‐SF and WW‐S‐SF rotations.