RWEQ: Improved wind erosion technology

ABSTRACT:

An improved wind erosion model (RWEQ) has been developed and validated with field erosion data from 45 site years. In RWEQ, the residue, soil erodibility, and soil roughness parameters are represented as coefficients. Within the RWEQ computer program, surface residues are decomposed with weather conditions. Residues are buried or flattened with tillage operations. Soil roughness is modified with tillage implements and roughness decayed with rainfall or irrigation amount and storm erosivity. Effect of wind barriers is described with an optical density index,but the protected zone downwind is dependent on wind velocity and soil surface conditions. Wind speed over bills is modified and the effect is included in soil loss estimates. Soil loss data were collected from sites with an annual range of rainfall of 191 to 1255 mm. Soil sand contents varied from 10 to 87%. The majority of the erosion data are from circular fields 2.6 ha in size, but data were aho collected from a 52 ha circle and rectangular fields 36 to 128 ha. Measured soil losses varied from 0 to 31.21 kg m² and estimated soil losses with RWEQ for the same sites varied from 0 to 39.15 kg M². Statistical correlation between measured and estimated values was significant. RWEQ has been tested on a broad range of soil, climate, and crop conditions, but additional testing may be needed on non mineral soils.