Indian Journal of Soil Conservation

K, the soil erodibility factor of USLE was estimated on three sets of natural rainfall runoff plots: set I - 3 plots of 0.5, 1.5 and 3.0 per cent slopes; set II, 3 plots of light, medium and medium heavy textured soils, these sets were conducted during 1953–68 and 4 plots of short duration (1969–71) were taken under set III. K, estimated from soil loss using K=A/RLSCP, was in a range of 0.216 to 0.558 with a mean of 0.416 t/ha. K, computed from Wischmeier and Smith equation employing modified silt (2–100 micron) fraction, ranged between 0.424 to 0.840 with a mean of 0.672 t/ha, that of 62 per cent increase over the estimated K. K, estimated from the same equation by employing USDA silt (2–50 micron) fraction as suggested in this paper, obtained in between 0.331 to 0.580 with a mean of 0.468 t/ha, that is only 13 per cent higher than experimental value. The classical USDA particle size fractions being reported in the triangular diagram can be employed with advantage in the Wischmeier and Smith equation/nomonograph for computing the value of K factor in the largely medium textured soils on mild slopes of the Indian Gangetic basin.