Early‐Season Wind Erosion Influenced by Soil‐Incorporated Green Manure in the Pacific Northwest

Core Ideas Irrigated soils in the Pacific Northwest are highly susceptible to wind erosion. Early‐season wind erosion potential was assessed from soil‐incorporated green manure and no green manure treatments. Soil‐incorporated green manure did not influence wind erosion. Management strategies are sought to minimize wind erosion of irrigated agricultural soils along the Columbia River of the Inland Pacific Northwest (PNW), particularly during the early season (March–April) when high winds coincide with sowing of vegetable crops. Early‐season wind erosion potential from soil‐incorporated green manure (i.e., incorporation of a cover crop of mustard into the soil in autumn) and no green manure treatments was assessed at two locations over 2 yr using a portable wind tunnel. Incorporation of green manure the preceding autumn did not influence wind erosion or soil erodible characteristics the following spring. Soil‐incorporated green manure, however, did influence early‐season crop residue characteristics. Although differences were significant, low residue cover and stem silhouette area suggested relatively small differences in empirical estimates of windblown soil loss between manure treatments. Soil crusting resulting from irrigation and/or rainfall prior to assessing wind erosion may have masked any influence of green manure on wind erosion. Due to the high erosion rates measured from the crusted soils, multiple years of green manure or minimum or reduced tillage may be required to promote aggregation and/or enhance residue cover and thereby reduce wind erosion of irrigated soils.