The effects of soil management systems and crop rotations were assessed from 1997 to 2003, in Passo Fundo, Rio Grande do Sul State, Brazil. Four soil management systems (no-tillage, minimum tillage, conventional tillage using disk plow, and conventional tillage using moldboard plow) and three crop rotation systems [system I (wheat/soybean), system II (wheat/soybean and common vetch/corn or sorghum), and system III (wheat/soybean, common vetch/corn or sorghum and white oats/soybean)] were compared. An experimental design of blocks at random with split-plots and three replications was used. The main plot consisted of soil management systems, while the split-plots consisted of crop rotation systems. Energy conversion (energy available/energy consumed) and balance (energy available - energy consumed) during a seven-year period is presented in this paper. No-tillage showed higher energy conversion and balance (72.44 and 190,766 MJ ha-1) than minimum tillage (64.06 and 167,349 MJ ha-1), conventional tillage using disk plow (54.35 and 134,982 MJ ha-1), and conventional tillage using moldboard (52.02 and 128,159 MJ ha-1), respectively. Wheat within crop rotations presented higher energy efficiency in energy than the monoculture of this cereal. The corn crop was observed the highest energy efficiency of this study.
energy conversion; energy balance; crop rotation; conventional tillage; minimum tillage; no-tillage
