Respuesta del cultivo de maíz bajo siembra directa a la reducción de la distancia entre hileras y al agregado de nitrógeno

• PABLO BARBIERI HERNÁN ECHEVERRÍA Y HERNÁN SAINZ ROZAS

Rosario, santa Fe

Congreso; VIII Congreso Nacional de Maíz; 2005

AIANBA

Under irrigation condition, no-tillage maize grown without adequate N intercepts less than 95% of the incident radiation at flowering. Reducing the distance between rows increases radiation interception during early stages and flowering and, in consequence, grain yield. However, under rainfed condition, a greater water transpiration at early stages of maize crops with plant spacing lower than 70 cm could reduce crop water consumption during the critical period of kernel set if water stress occurs at that time. An experiment was carried out at INTA Balcarce in 2001/02 and 2002/03 to evaluate row spacing and N availability effects on radiation interception (RFAint), dry matter (DM) and grain yield in rainfed maize crop. Treatments consisted of a factorial combination of row width (70 and 35 cm) and N rate (0 and 180 kg N ha-1). In both years, N rate increased grain yield (4625 and 9761kg ha-1, for 0 and 180 kg N ha-1, respectively), and DM at physiological maturity (PM) (8546 and 16639 kg ha-1, for 0 and 180 kg N ha-1, respectively). In both years, narrow rows increased RFAint during the growing season, and in consequence DM (13067 and 12117 kg ha-1, for 35 and 70 cm, respectively) and grain yield at PM (7903 and 6523 kg ha-1, for 35 and 70 cm, respectively). The increase of grain yield by narrow rows was lower in  2002/03 than in 2001/02 because of the occurrence of moderate water stress during the critical period of kernel set . Therefore, the results of this experiment show that narrow rows increased DM and grain yield at PM, even under  rainfed conditions.   Palabras clave: maíz,  distancia entre hileras, nitrógeno. Key words: maize, row spacing, nitrogen.