RWEQ: Improved wind erosion technology

An improved wind erosion model (RWEQ) has been developed and validated with field erosion data from 45 site years. In RWEQ, the residue soil credibili ty, and soil roughness parameters are represented as coefficients. Within t he RWEQ computer program, surface residues are decomposed with weather cond itions. Residues are buried or flattened with tillage operations. Soil roug hness is modified with tillage implements and roughness decayed with rain-f all or irrigation amount and storm erosivity. Effect of wind barriers is de scribed with an optical density index, but the protected zone downwind is d ependent on wind velocity and soil surface conditions. Wind speed over hill s is modified and the effect is included in soil loss estimates. Soil loss data were collected from sites with art annual range of rainfall of 191 to 1255 mm. Soil sand contents varied from 10 to 87%. The majority of the eros ion data are from circular fields 2.6 ha in size, but data were also collec ted from a 52 ha circle and rectangular fields 36 to 128 ha. Measured soil lasses varied from 0 to 31.21 kg m(2) and estimated soil losses with RWEQ f or the same sites varied from 0 to 39.15 kg m(2). Statistical correlation b etween measured and estimated valuer was significant RWEQ has been tested o n a broad range of soil, climate, and crop conditions, but additional testi ng may be needed on non mineral soils.