Application stages and nitrogen sources in topdressing of super-early bean crop irrigated

Producing food in a sustainable manner, exploiting the genetic potential of crops and optimizing cultivation time to ensure increased production are the biggest challenges for agriculture. The cultivation of super-early common bean lineages with high productive capacity leads to minor water consumption in crops under irrigation and vacate the area in less time. The objective of this work was to evaluate the yield components of super-early cycle common bean cultivars, under irrigated system in function of sources of nitrogen (N) as well as to assess different application stages. The experiment was conducted in randomized block design in a factorial scheme 4x3 + 1, corresponding of four sources of N in coverage (urea, urea + ammonium sulfate, urea + ammonium sulfate + elemental sulfur and urea + elemental sulfur), three application stages (V3, V4 and R5) and a control treatment. The N incorporation did not influence on the grain yield of the super-early cycle common bean regardless of the source and season, whereas significant results were merely found when compared to the control. The number of pods was affected when the application was carried out at the R5 stage, with a significant reduction in this yield component. The relative chlorophyll index was lower when nitrogen coverage was performed at the R5 stage.