Evaluating the crop and management factor C for applying RUSLE at plot scale

The successful application of empirical models like RUSLE for estimating soil erosion in rangeland areas depends heavily on the availability of reliable procedures for evaluating the crop and management factor C. In many cases such procedures make important assumptions regarding the plant growth component in response to land use for both annual and perennial plants. Such assumptions are frequently untested and the associated models thus remain largely invalidated. This contribution describes the results of an experiment involving 9 experimental plots located in Southern Italy aimed at validating several of the assumptions commonly associated with the use of RUSLE for estimating soil erosion at plot scale. At first, the soil loss measurements carried out in 2001 and 2002 are used to evaluate the crop and management factor for perennial plants. Then, an independent procedure involving biomass measurements for evaluating the C factor is proposed. Finally, a Monte Carlo technique is used for evaluating the effects of the knowledge uncertainty and the stochastic variability of the model parameters on calculated soil loss.