A growing concern about development of herbicide resistance in different weeds species, the environmental side effects of herbicide and the need to reduce the cost of inputs have promoted the development of integrated weed management program based on rationalisation of herbicide use. A cultural alternative such as modifying crop competitive ability is an important strategy to include in an IWM program. The objective of this study was to analyze the effect of maize row spacing and herbicide application on (i) soil water content and photosynthetically active radiation (PAR) dynamics, (ii) belowground and aboveground corn biomass and grain yield and (iii) weed suppressive ability of dryland corn planted at narrow and wide rows. Field experiments were conducted during 2002/2003 and 2003/2004 growing seasons. Three corn hybrids with two-row width (0.70 and 0.35 m) and two herbicides rate (1.0 X and 0.0 X) were tested. It was observed that from initial stages of the crop, there was greater moisture content in the row of corn planted at narrow row arrangement while, a lower soil water content in maturity was observed. Conversely, between rows, the narrow row arrangement registered lower soil water content during the growing cycle of crop. This soil water profile was a consequence of the uniform corn belowground dry matter distribution observed. A greater PAR interception with a lower weed aboveground dry matter in narrow row arrangement was obtained. Corn grain yield was greater in the narrow row arrangement than in the wide row spacing. This increase in grain yield was related to a better resources use (soil moisture and PAR interception) that allows for a reduced interspecific competition. The use of reduced spatial arrangement appeared as an interesting alternative to increase both the grain yield potential and corn suppressive ability against weeds in dryland Argentinean production systems