Surface Residue and Soil Roughness Forwind Erosion Protection

Research to determine the off-site downwind impact of wind erosion of soil was conducted in the ColumbiaPlateau region of Washington State. As part of this project, mathematical relationships were determined for the combinedeffectiveness of flat plant residue and soil surface random roughness, then compared to similar equations derived fromprevious research. Data were obtained using a portable wind tunnel 1.0 m wide, 1.2 m high with a working section 7.3 mlong. Eroded soil was collected using a vertical slot sampler 0.75 m high, 0.003 m wide and near isokinetic at three tunnelvelocities. The mass of eroded soil was expressed as a ratio of that from an adjacent smooth, bare soil, then regressed againstmeasured flat residue surface cover and random roughness. Predicted soil loss ratio values from the derived equationcompared to the measured values with a slope of 0.96 and an r2 of 0.51. The derived equation was very similar to that ofprevious research from a region with quite different characteristics which suggests universality of the relationships.