Economic analysis of crop rotation systems for wheat, over a ten year period, under no-tillage

From 1984 to 1993, in Guarapuava, Parana, Brazil, the effect of crop rotati on systems on wheat were assessed. Four rotation systems for wheat were stu died: system I (wheat/soybean); system II (wheat/soybean and common vetch/c orn, from 1984 to 1989, and wheat/soybean and white oats/soybean, from 1990 to 1993); system III (wheat/soybean, flax/soybean, and common vetch/corn, from:1984 to 1989, and wheat/soybean, common vetch/corn, and white oats/soy bean, from 1990 to 1993); and system IV (wheat/soybean, legume/corn, barley /soybean, and white oats/soybean). The economic analysis on that period is presented in this paper. From 1984 to 1989, systems I, II, III, and IV show ed no differences in their net return means. Similarly, from 1990 to 1993, systems II, III, and IV mean net returns did not differ significantly in re lation to the system I; however, considering the annual comparison, the sys tem II showed higher profit than the system I in six years and did not diff er in four years, making it a good alternative, mainly in the first period.