The impact of maize stand density on herbicide efficiency

Abstract

The impact of maize stand density (4, 8 and 12 plants per m²) on herbicide efficiency (in %) and cob yield loss (in %) was studied in four field trials. The mixture of soil-applied herbicides (HS) isoxaflutole and S-metolachlor and the mixture of foliar-applied herbicides (HF) dicamba and rimsulfuron was applied in two dosages (100 and 75% of dose recommended by manufacturers). The 100% dose of HS was (75 g isoxaflutole + 960 ml S-metolachlor) per ha and 100% dose of HF was (12.5 g rimsulfuron + 240 ml dicamba) per ha. In all four trials, the studied factors (stand density, herbicide type and dose) had significant impact on herbicide efficiency and on maize cob yield loss. The herbicide efficiency decreased significantly, when herbicides were applied to maize of lower stand density and the maize yield losses increased. When weed population was composed predominantly of annual seed weeds higher efficiency was obtained by HS herbicides, conversely, when the weed population was composed predominantly of perennial weeds the HF herbicides provided better control. The reduction of herbicide dose always caused the significant reduction in herbicide efficiency and increase in maize yield loss.