The production of biomass and oat grains is directly dependent on the forms of nitrogen (N) supply. The objective of this study was to determine the efficiency of utilization of N-fertilizer on biomass and grain oat in high and reduced N-residual release in different cropping systems and estimate the maximum technical and economic efficiency of grain yield in identifying cultivars more efficient in the use of N. The study was conducted in the years 2011 and 2012 in a randomized block design with four replications in a 4 x 2 factorial with four nitrogen rates (0 , 30 , 60 and 120 kg ha-1) and two oat cultivars (Barbarasul and Brisasul) in soybean/oat and corn/oat system. There is a tendency of increase in growth rate in oat biomass with increasing doses of N-fertilizer in both cropping systems, however, condition is not always accompanied by the increased productivity of grain. The cultivar Brisasul shows greater efficiency in the utilization of N in the elaboration of biomass and grain, independent of the production system. The definition of adjusted dose in oats allows more advantageous results by analysis of maximum economic efficiency for grain yield.
Avena sativa L.; urea; C/N ratio; technical efficiency and economic
