Crop rotation in Guarapuava. XVII. Energetic efficiency of rotation systems for barley crop, under no-tillage

Abstract

In the period from 1984 to 1989, at the Cooperativa Agrária Mista Entre Rios Ltda., in Guarapuava, PR, Brazil, the effects of rotation systems for barley on energetic efficiency were assessed. Four rotation systems for barley were studied: 1) monoculture; 2) one winter without barley; 3) two winters without barley; 4) three winters without barley. Both winter (white oat, barley, common vetch, and flax) and summer (corn and soybean) crops were seeded under no-tillage. The energetic efficiency is the ratio of grain yield of each crop by the cropping energy, represented by the commodities and labor executed in the cropping systems. Energetic efficiency of crops studied was influenced by the cropping period. White oat and barley crops showed higher energetic efficiency than the other winters crops. The best energetic efficiency was obtained for corn.