The Effects of Rain and Overland Flow Powers on Agricultural Soil Erodibility

The purpose of this investigation is to relate the rain power and the overland flow power to soil erodibility to assess the effects of both parameters on soil erosion using variable rainfall intensity on remoulded agricultural soil. Six rainfall intensities were used to simulate the natural rainfall and are as follows: 12.4mm/h, 20.3mm/h, 28.6mm/h, 52mm/h, 73.5mm/h and 103mm/h. The results have shown that the relationship between overland flow power and rain power is best represented by a linear function (R2=0.99). As regards the relationships between soil erodibility factor and rain and overland flow powers, the evolution of both parameters with the erodibility factor follow a polynomial function with high coefficient of determination. From their coefficients of determination (R2=0.95) for rain power and (R2=0.96) for overland flow power, we can conclude that the flow has more power to detach particles than rain. This could be explained by the fact that the presence of particles, already detached by rain and transported by the flow, give the flow more weight and then contribute to the detachment of particles by collision.




References:
[1] Aggassi M.; Bradford J.M. (1999) "Methodologies for interrill soil
erosion studies". Soil and Tillzge Research 49, pp: 277-287.
[2] Bryan R.B. (2000) "Soil erodibility and processes of water erosion on
hillslope". Geomorphology 32, pp: 385-415.
[3] Gabet, E.J. and T. Dunne (2003) Sediment detachment by rain power,
39, No 1, pp: 1-12.
[4] Guy, B.J.;W.T.Dickinson and Rudra, R.P. (1990) "Hydraulics of
sediment-laden sheet flow and the influence of simulated rainfall". Earth
Surface Processes and Landforms, vol.15, pp: 101-118.
[5] Kinnell, P.I.A. (1993) "Runoff as a factor influencing experimentally
determined interrill erodibilities". Aust. Jour. Soil Resear. 31, pp: 333-
342.
[6] Li, G. (2009) "Preliminary study of the interference of surface objects
and rainfall in overland flow resistance", Catena 78, pp: 154-158.
[7] Morgan, R.P.C. (1977). "Soil erosion in the United Kingdom: Field
studies in the Silsoe area, 1973-1975". Silsoe Occasional paper, number
4, 41p.
[8] Moussouni, A., Mouzai L. and Bouhadef M. (2012) "Laboratory
experiments: Influence of rainfall characteristics on runoff and water
erosion", Waset, 68, pp: 1540-1543.
[9] Nearing M.A., L.D. Norton, D.A. Bulkakov, G.A. Larionov L.T. West,
and K.M. Dontsova (1997) "Hydraulics and erosion in eroding rills".
Water Resources Research, vol. 33, N┬░4, pp: 865-876.
[10] Tan, S.K. (1989) "Rainfall and soil detachment". Jour. of Hyd. Res.
Vol.27 (5), pp: 699-715.