Risk analysis of crop rotation systems for barley, over a ten-year period, in no-tillage system

From 1984 to 1993, in Guarapuava, PR, Brazil, the effects of crop rotation systems for barley (Hordeum vulgare L.) were assessed. The risk analysis of these systems is presented in this paper. Four rotation systems for barley were studied: I (barley/soybean); II (barley/soybean and common vetch/corn, from 1984 to 1989, and barley/soybean and white oats/soybean, from 1990 to 1993); III (barley/soybean, flax/soybean, and common vetch/corn, from 1984 to 1989, and barley/soybean, common vetch/corn, and white oats/soybean, from 1990 to 1993); and IV (barley/soybean, flax/soybean, common vetch/corn, and white oats/soybean). A randomized block design was used, with four replications and plots totalizing 60 m(2). Two types of analyses were applied on the net return of the systems: mean-variance analysis and risk analysis (safety-first and stochastic dominance). Identification of the best system studied through 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.