Risk analysis of four crop rotation systems for wheat, over a ten-year period, in Passo Fundo, RS

During ten years (1980 to 1989), at the Embrapa-Centro Nacional de Pesquisa de Trigo (CNPT), in Passe Fundo, RS, Brazil, the effects of crop rotation systems on wheat (Triticum aestivum L.) were assessed. Four rotation system s for wheat were studied: system I (wheat/soybean); system II (wheat/soybea n, rapeseed/soybean, barley/soybean, lupine or serradella/corn); system III (wheat/soybean, arrowleaf clover/arrowleaf clover, and arrowleaf clover/co rn, from 1980 to 1983, and wheat/soybean, white oats/soybean, and common ve tch/corn, from 1984 to 1989); and system IV (wheat/soybean, rapeseed/soybea n, flax/soybean, and lupine or serradella/com). A randomized complete block design, with four replications and plots with 120 m(2), was used. Risk ana lysis over that period is presented in this paper. Two types of analysis we re applied to the net return of the systems: mean-variance analysis and ris k analysis (safety-first and stochastic dominance). By the mean-variance an alysis, systems II and IV showed higher net returns as compared to systems I and III. The system II showed the highest profit and the lowest risk to b e offered to the farmer, as compared to the remaining systems studied.