Eficiencia de uso de nitrógeno en el cultivo de maíz bajo siembra directa en función de la distancia entre hileras y la disponibilidad de nitrógeno

• PABLO BARBIERI HERNÁN ECHEVERRÍA Y HERNÁN SAINZ ROZAS

Rosario, Santa Fe

Congreso; VIII Congreso Nacional de Maíz; 2005

AIANBA

Nitrogen (N) use efficiency (NUE) is an important aspect to consider in no till-corn N management. An experiment was carried out at INTA Balcarce in 1999/00 and 2000/01 to evaluate row spacing and N availability effects on NUE expressed as dry matter (DM) or grain yield per unit of available N. Treatments consisted of a factorial combination of row width (70, 52 and 35 cm) and N rates (0, 90 and 180 kg N ha-1). At physiological maturity total DM, grain yield and accumulated N were determined. In both years, N rate increased DM (12573, 16539 and 18068 kg ha-1, for 0, 90 and 180 kg N ha-1, respectively) and grain yield (7190, 9714 and 10860 kg ha-1, for 0, 90 and 180 kg N ha-1, respectively). Dry matter and grain yield responses to narrower rows (52 and 35 cm) decreased as N availability was increased. Dry matter was increased by 13, 3 and 0.6%, for 0, 90 and 180 kg N ha-1, whereas grain yield was increased by 16, 4 and 0.4%, for 0, 90 and 180 kg N ha-1, respectively. Narrow rows increased DM or grain yield per unit of available N, and in consequence NUE at medium or low N availability. Physiological efficiency (PE), expressed as DM or grain yield per unit of N uptake was not affected by row spacing because of the greater N accumulation in the treatments with narrower rows. Therefore, results of this experiment show that narrow rows increased DM or grain yield because of a greater N recovery fraction.   Palabras clave: maíz, eficiencia de uso del nitrógeno, distancia entre hileras. Key words: maize, nitrogen use efficiency, row spacing.