Oilseeds Modify Windblown Soil Characteristics in Dryland Cropping Systems.

Although oilseeds have been promoted for the production of biofuel, there is evidence to suggest a greater risk for wind erosion when growing oilseeds in conventional winter wheat rotations in the Inland Pacific Northwest. Little is known about windblown soil surface characteristics of oilseed cropping systems. Crop residue biomass and soil water content, roughness, strength, and aggregate size distribution were measured immediately after sowing winter wheat in a winter wheat – summer fallow (WW-SF) and winter wheat- camelina – summer fallow (WW-C-SF) or winter wheat – safflower – summer fallow (WW-S-SF) rotation near Lind and Ritzville, Washington. Oilseeds (camelina and safflower) grown in a conventional WW-SF rotation did not affect soil water content, random roughness, penetration resistance, geometric mean diameter, or the erodible fraction, but did result in lower prostrate residue biomass and cover. Sediment transport was estimated by the Revised Wind Erosion Equation to be 55 to 210% greater for the WW-C-SF or WW-S-SF than the WW-SF rotation due to differences in crop residue characteristics after sowing wheat. Crop residue must be carefully managed to minimize wind erosion from dryland oilseed cropping systems in the Pacific Northwest.