NITROGEN SOURCES, FORMS OF APPLICATION AND DOSES IN IRRIGATED COMMON BEAN UNDER NO-TILLAGE SYSTEM

Abstract

The loss of nitrogen by ammonia volatilization is the main factor responsible for the low utilization of urea, especially when applied to the soil surface. This experiment evaluated the efficiency of urea containing 0,045% of NBPT (n-butyl thiophosphoric triamide) addictive, when compared with regular urea, and the effects of rates and forms of application of covering nitrogen over irrigated common bean component parts and yield, cultivated under no-tillage system, on a Distrudox soil, managed for three consecutive years under crop-livestock integrated system. A randomized complete blocks design was used, in a 2x2x4 factorial scheme, consisting of two nitrogen sources (common and additivated urea), two application methods (surface and incorporated), and four N doses (0 kg ha-1, 60 kg ha-1, 120 kg ha-1, and 180 kg ha-1), with four replications. When compared to the common urea, additivated urea did not provide significant increases in yield. The additivated source resulted in higher plants and it was noticed a higher yield rate, when the fertilizer was used.

KEY-WORDS: Phaseolus vulgaris L.; crop-livestock integrated system; yield.