A field experiment of soil and water losses by erosion was carried out during six consecutive agricultural years (1973/74 to 1978/79) at the Experimental Center of Campinas, Instituto Agronomico of São Paulo, Brazil, in a Typic Haplorthox, to evaluate soil loss ratio (SLR) for three green manures: Crotalaria juncea L., Stizolobium aterrinum Piper et Tracy and Dolichos lablab L. Four cropstage periods were defined as isolated periods (0-30, 30-60, 60-90, and 60-120 days after planting), and as accumulated cropstage period (0-30, 0-60, 0-90 or 0-120 days after planting). The results showed that Stizolobium aterrinum gave the best cover protection against soil loss, with values of soil loss ratio (SLR) of 0.28, 0.37, 0.17 and 0.19 for cropstage periods of 0-30, 30-60, 60-90 and 60-120 days after planting, respectively. Dolichos lablab showed SLR values of 0.50, 0.45, 0.27 and 0.19 and Crotalaria juncea of 0.30, 0.42, 0.26 and 0.24 for the same cropstage periods, respectively. The results also showed that the cover protection from the three green manures was more effective after 60 days of planting. Stizolobium was the most efficient cover, followed by Crotalaria, mainly in the first cropstage period and Dolichos, during flowering.
erosion; vegetal cover; green manure; cover and management factor