Row Width and Maize Grain Yield

MADDONNI, G.A.; CIRILO, A.G.; OTEGUI, M.E.

AGRONOMY JOURNAL

American Society of Agronomy

Lugar: Baltimore; Año: 2006 vol. 98 p. 1532 - 1543

0002-1962

Maize (Zea mays L.) grain yield increase in narrow rows (0.35–0.50 m) may be related to the improvement of light interception around silking, but percentages of grain yield increase are generally lower than those of light interception, suggesting a lower efficiency to convert the amount of intercepted photosynthetic active radiation (IPAR) into aboveground phytomass.We analyzed the effects of plant population and row spacing on grain yield and its components (kernel number and kernel weight) and on the underlying processes, the IPAR around silking and during the effective grain filling period, and radiation use efficiency (RUE) during both periods. Field experiments were conducted in Argentina from 1997 to 2001. Five hybrids were cultivated at a wide range of plant population densities (3, 4.5, 9, and 12 plants m-2) and row spacings (0.35, 0.50, 0.70, and 1 m) without water and nutrient limitations. Row spacing reduction increased IPAR around silking at low plant densities (»8 and 4% for 3–4.5 and 9–12 plants m-2, respectively) but did not modify RUE during this period. Morphogenetic limitations in the reproductive organs of plants (number of florets per ear) cultivated at low stand densities, suppressed the slight benefits of enhanced light capture under narrow rows, yielding similar kernel numbers at any row spacing. Contrarily, a postsilking RUE reduction (»13–16%) of crops in narrow rows compared to those in wide rows minimized or counterbalanced any positive effect on IPAR during the grain-filling period. Hence, for the tested growing conditions, no benefits could be expected in terms of grain yield by reducing row spacing from the present 0.7- to 0.8-m inter-row distance.