Análise agronômica, econômica e energética de sistemas de produção agrícola para a região norte do Rio Grande do Sul

Abstract

Agriculture needs to analyze production systems and not only cultures separately, in order to verify suitable cultural successions that complete high productivity, rentability and energy. The objective of this work is to evaluate agronomic, economic and energetic results of agricultural production systems with different cultures in winter and summer crops under direct sowing system, defining the best production system to the North Region of Rio Grande do Sul State, Brazil. Two experiments were accomplished,once the first one being soybeans growing, and the second one on corn growing, with winter/spring cultures (fallow, green coverage, turnip/wheat, wheat, white oat, sunflower and peas) and subsequently with summer cultures (soybeans, corn and beans). In the soybeans experiment as well as in corn, the bigger grain yields were obtained in the treatment with wheat, which had as green coverage the turnip forage between summer culture of previous crop and wheat sowing, resulting in greater economic return and high straw production to the direct sowing system. Greater grain yield of soybeans was after green coverage growing (white oat + turnip). Corn sowing achieved in the first period stood out (over peas and green coverage), showing the importance of the time of sowing. Canola sowing on corn straw can not be carried out due to suitable plant population is not established to generate stability. Production systems that better represent the three requirements (grain yield, operational and energetic margin), were soybeans peas corn, soybeans green cover corn and corn turnip/wheat soybeans