Hp. Dossantos et Em. Reis, CROP-ROTATION IN GUARAPUAVA, PR BRAZIL .1 6. ENERGETIC EFFICIENCY OF ROTATION SYSTEMS FOR WHEAT, UNDER NO-TILLAGE, Pesquisa agropecuaria brasileira, 30(2), 1995, pp. 215-222
From 1984 to 1989, at the Cooperativa Agraria Mista Entre Rios Ltda.,
in Guarapuava, PR, Brazil, plant species composing rotation systems fo
r wheat on energetic efficiency were assessed. Four rotation systems f
or wheat were studied: 1) monoculture; 2) one winter without wheat; 3)
two winters without wheat; 4) three winters without wheat. Both winte
r (white oat, barley, common vetch, flax, wheat, and lupin) and summer
(corn and soybean) crops were seeded under no-tillage. The energetic
efficiency is calculated by dividing the grain yield of each crop by c
ropping energy, represented by the commodities and labor employed in t
he cropping systems. Energetic efficiency of crops studied was affecte
d by the period. White oat, barley, and wheat crops showed higher ener
getic efficiency compared to other winter crops. The best energetic ef
ficiency was obtained by corn.