COVER CROPS AND NITROGEN FERTILIZATION - NUTRITIONAL ASPECTS AND AGRONOMIC PERFORMANCE OF MAIZE GROWN IN SUCESSION

Resumo

Cover crops can contribute differently to the supply of nitrogen to crops. The objective was to evaluate the response of maize to nitrogen doses (0, 70, 140, 210 and 280 kg ha-1) when grown in succession to cover crops (vetch, forage turnip, black oat, ryegrass and fallow). The randomized block experimental design was used, with subdivided plots and four replications. Cover crops were allocated into plots, and N doses into sub-plots. As to cover crops, the aspects evaluated were phytomass production, N content and total accumulated; with regard to maize, the aspects evaluated were SPAD (Soil Plant Analysis  evelopment) index, leaf N content, total grain protein, yield and agronomic efficiency of N. Black oat, ryegrass and forage turnip presented higher phytomass production. All species had similar results as to the total N accumulated in the aerial part (average value of 91.06 kg ha-1). In succession to black oat, ryegrass and fallow period, N doses up to 140 kg ha-1 applied in maize result in higher yield and better agronomic efficiency of nitrogen use. Without application of nitrogen (0.0 kg ha1), forage turnip and vetch provided higher total protein content in the grain, yield over 8,550 kg ha-1, and less agronomic efficiency of nitrogen use.