RISK ANALYSIS OF CROP-ROTATION SYSTEMS FOR BARLEY, OVER A 10-YEAR PERIOD, IN NO-TILLAGE SYSTEM

From 1984 to 1993, in Guarapuava, PR, Brazil, the effects of crop rota tion systems for barley (Hordeum vulgare L.) were assessed. The risk a nalysis of these systems is presented in this paper. Four rotation sys tems for barley were studied: I (barley/soybean); II (barley/soybean a nd common vetch/corn, from 1984 to 1989, and barley/soybean and white oats/soybean, from 1990 to 1993); III (barley/soybean, flax/soybean, a nd common vetch/corn, from 1984 to 1989, and barley/soybean, common ve tch/corn, and white oats/soybean, from 1990 to 1993); and IV (barley/s oybean, flax/soybean, common vetch/corn, and white oats/soybean). A ra ndomized block design was used, with four replications and plots total izing 60 m(2). Two types of analyses were applied on the net return of the systems: mean-variance analysis and risk analysis (safety-first a nd stochastic dominance). Identification of the best system studied th rough mean-variance analysis was not feasible. Through the stochastic dominance method the system II was the best production alternative to be offered to the farmer from both profit and lower risk standpoints.