Soil and water loss under natural rainfall in Lages (SC - Brazil), from November 1992 to October 1998, were used to calculate soil loss ratio (SLR) and C factor for the Universal Soil Loss Equation (USLE) under three soil tillage systems and two crops. Treatments studied were plowing followed by two disking (P+D), chiseling plus disking (C+D) and no-tillage (NT), cultivated in succession with soybean (Glycine max) and wheat (Triticum aestivum L.), compared to a check plot: plowing followed by disking without crops (PDW), on an Inceptisol with 0.102 m m-1 slope. Five growing stages of crops were selected with equal interval time among them. The SLR and C factor varied among soil tillage systems, crop stages, same-crop and between-crop cycles, and indicating a strong effect of the soil management and rainfall over those variables. The SLR values for soybean crop were 0.1711, 0.1061 and 0.0477 for the P+D, C+D and NT soil tillage systems, respectively while for wheat crop the referred SLR values for the respective soil tillage systems were 0.2416, 0.1874 and 0.0883. For the above mentioned soil tillage systems, the C factors were 0.1437, 0.0807 and 0.0455 for the soybean crop, 0.2158, 0.1854 and 0.0588 for the wheat crop and, for the soybean/wheat crop succession, 0.3713, 0.2661 and 0.1043.
universal soil loss equation; water erosion; conservation tillage