Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.1998.244.247FarmanullahKhan SatoKoichi TakaseKeiji 4199814Experiments to investigate the effect of soil cohesion under steady and uniform flow conditions were carried out in a laboratory flume at different slope degrees. Six samples of soils, four sandy and two loam soils were used. From the relationship of critical flow, slope and particle diameter, an equation was derived, which can be expressed as: qc = a (Sin θ)^{m}. The equation shows that the basic response of decreasing critical flow with an increase in slope degree is the same for both loam and sandy soils. However, due to water stable aggregates and soil cohesion, the critical flow is greater in loam soils as compared to the critical flow in non cohesive sandy soils. The derived empirical relationships can be used to assist the effect of soil cohesion on rill initiation and can therefore contribute to the development of physically based rill erosion models.]]>Bryan, R.B.,1987Chaney, K. and R.S. Swift,1984Koh, M. and K. Sato,1988Luk, S.H.,1979Tisdall, J.M. and J.M. Oades,1982Verhaegen, T.,1984Wischmeier, W.H. and L.D. Meyer,1973Young, R.A. and C.K. Mutchler,1977