NITROGEN USE EFFICIENCY IN MAIZE AS AFFECTED BY NITROGEN AVAILABILITY AND ROW SPACING

PABLO A. BARBIERI, HERNÁN E. ECHEVERRÍA AND HERNÁN R. SAÍNZ ROZAS

AGRONOMY JOURNAL

ASA

Lugar: Madison, WI; Año: 2008 vol. 100 p. 1091 - 1100

0002-1962

ABSTRACT Effi cient use of N in plant production is an essential goal in crop management. An experiment was performed at INTA Balcarce, Argentina during 3-yr to evaluate the eff ect of row spacing and N level on nitrogen use effi ciency (NUE) in no-till (NT) irrigated maize (Zea mays L.). Treatments consisted of a factorial combination of row width (70, 52 and 35 cm) and N rates (0 to 180 kg N ha−1). Nitrogen rate and narrow rows increased total dry matter (DM), grain yield, and N accumulation. Relative responses to narrow rows decreased as N availability increased. Th e NUE decreased with N rate and increased with narrow row spacing. Narrow rows increased NUE by 12 and 15% expressed as DM or grain yield per unit of available N, respectively. Physiological effi ciency decreased with N rate and was not aff ected by row spacing. Recovery effi ciency (RE) decreased with increasing N rate, and increased for the narrow row spacings. The effect of narrow rows on RE decreased as N availability increased. Narrow rows increased NUE largely as a result of increased RE. Th ese increments in RE could contribute to increase the profi tability of maize production and to diminish the risk of environmental pollution.Zea mays L.). Treatments consisted of a factorial combination of row width (70, 52 and 35 cm) and N rates (0 to 180 kg N ha−1). Nitrogen rate and narrow rows increased total dry matter (DM), grain yield, and N accumulation. Relative responses to narrow rows decreased as N availability increased. Th e NUE decreased with N rate and increased with narrow row spacing. Narrow rows increased NUE by 12 and 15% expressed as DM or grain yield per unit of available N, respectively. Physiological effi ciency decreased with N rate and was not aff ected by row spacing. Recovery effi ciency (RE) decreased with increasing N rate, and increased for the narrow row spacings. The effect of narrow rows on RE decreased as N availability increased. Narrow rows increased NUE largely as a result of increased RE. Th ese increments in RE could contribute to increase the profi tability of maize production and to diminish the risk of environmental pollution.