Response of Corn (Zea mays) and Weeds to Planting Pattern and Herbicide Use

Abstract

ABSTRACT The use of narrow row arrangement in corn (Zea mays) has been suggested as a technological alternative to obtain grain yield increases through a better use of the resources. The regular pattern could diminish intraspecific competition while favouring interspecific competition with weeds. The objective of this study was to analyse the effect of corn planting pattern and herbicide application on (i) soil water content and photosynthetically active radiation (PAR) dynamics, (ii) below ground and above ground corn biomass and grain yield and (iii) weed suppressive ability of dryland corn sown at square and rectangular plant arrangement. Field experiments were conducted during the growing seasons 2002/03 and 2003/04. Three corn hybrids with two plant arrangement (rectangular: 0.70 × 0.20 m and square: 0.35 × 0.35 m) and herbicide (2.25 kg ai ha−1 of atrazine and 2.32 kg ai ha−1 of metolachlor) use compared with no herbicide use were tested. In the initial stages of the crop there was greater moisture content in the row of corn sowed at square planting pattern while a lower soil water content at maturity was observed. Conversely, between rows, the square plant arrangement registered lower soil water content during the growing cycle of the crop. This soil water profile was a consequence of the uniform corn below ground dry matter distribution. A greater PAR interception with a lower weed above ground dry matter was obtained in square plant arrangement. Corn grain yield was greater in the square-planting pattern than in the rectangular ones. This increase in grain yield was related to better resources use i.e. soil moisture and PAR interception while reduces the competition from weeds. The use of equidistant plant arrangement appeared as an interesting alternative to increase both the grain yield potential and the corn suppressive ability against weeds in dryland Argentinean production systems.