REVIEW OF RESUSPENSION MODELS 21 7 



10 20 



PERCENT < 0,1 mm 



Fig. 1 Suspension flow vs. percent of grains in soil <0.1 mm. 



due to the cohesion of the absorbed water films. However, it is noted that the water 

 content of a field can decrease rapidly following a rain owing to the drying actions of the 

 winds. 



Many other factors influence the erosion of the field, such as the presence or absence 

 of ridges, the quantity of vegetative cover, and the presence or absence of a surface crust. 

 These have been combined to give a soil-erosion equation (Chepil, 1960; Woodruff and 

 Siddoway, 1965) 



E = f(l',C',K',L',V) 



(5) 



where E = potential average annual soil loss (tons per year) 



r = soil and knoll erodibility 

 C' = local wind-erosion cUmatic factor 

 K' = soil ridge roughness factor 

 L' = field-length factor 



V = equivalent quantity of vegetation 



Mathematical relations have been established between the individual variables. The 

 relationships, however, are so complex that the individual factors are evaluated separately 

 in a form in which combinations of the factors can be evaluated graphically. 



