Nitrogen loss from windblown agricultural soils in the Columbia Plateau

Abstract

Abstract Wind erosion of agricultural soils can degrade both air quality and soil productivity in the Columbia Plateau of the Pacific Northwest United States. Soils in the region contain fine particles that, when suspended, are highly susceptible to long range transport in the atmosphere. Nitrogen (N) associated with off-site transport of windblown particulate matter depletes the parent soil of nutrients important in sustaining the biological activity of soils. The objective of this study was to quantify the loss of N from eroding agricultural fields during high wind events. Soil eroded from fields subject to conventional tillage in winter wheat–summer fallow rotations in eastern Washington was trapped in creep and Big Spring Number Eight (BSNE) samplers installed on the leeward side of fields at heights of 0–1.5 m above the surface. The location of field sites varied over the 8 years of this study, but all sites were characterized by soils with a silt loam texture and annual precipitation of ⩽305 mm. Nitrogen content of the parent soil ranged from 0.063% to 0.090% while N content of sediment trapped by the samplers during high winds ranged from 0.053% to 0.101%. Enrichment ratios (ERs) for N ranged from 0.8 to 1.3, indicating the sediment was not highly enriched in N as compared with the parent soil. Nitrogen loss was estimated to range from 0.1 to 1.9 kg ha−1 during a high wind event. Nitrogen loss may be reduced by using conservation practices that have been proven effective in controlling wind erosion.