The objective of this work was to determine the effects of N management on yield and agronomic traits of common bean and the profitability of N application. The experiment was carried out for three years on varzea (lowland) soil. In the first two years, N doses used were 0, 40, 80, 120, and 160 kg ha-1 and N applications were as follows: all N applied at sowing, ½ at sowing + ½ incorporated in the soil at 20 days after plant emergence and ½ at sowing and ½ applied as topdressing 20 days after plant emergence. In the third year, N doses applied at 20 days after plant emergence and incorporated in soil were evaluated in three localities. The bean cultivars used were Rudá in the first two years and Pérola in the last one. Maximum economical grain yield of 2.700 kg ha-1 was obtained in Pérola cultivar with the application of 167 kg ha-1 of N incorporated in the soil at 20 days after plant emergence; N dosage of 108 kg ha-1 provided 90% of maximum grain yield. The most appropriate N application timing was part at sowing and part incorporated in the soil. Common bean crop requires more N in varzea soils than in upland soils.
Phaseolus vulgaris; yield components; nitrogen fertilizers; fertilizer application; agronomic characters
