Merits of a weed-sensing sprayer to control weeds in conservation fallow and cropping systems

Abstract

Field studies were conducted from 1993 through 1995 to determine potential reductions in herbicide use and associated cost savings by utilizing a weed-sensing sprayer, named Detectspray, to control weeds throughout the fallow season and to control perennial weeds after crop harvest. The Detectspray system gave comparable weed control to conventional broadcast spraying on 80% of the application dates and reduced glyphosate/dicamba use over the fallow season by 19 to 60%. This reduced herbicide use resulted in cost savings of $6 to $32 ha⁻¹. A fallow treatment that combined two herbicide applications with the Detectsprayer plus one to two wide-blade tillage operations was less costly than conventional tillage at two of 11 sites and at all sites retained more surface crop residues to reduce the risk of erosion. Postharvest glyphosate use on quackgrass with the Detectsprayer was reduced 50 to 78% compared to broadcast applications and resulted in cost savings of $16 to $25 ha⁻¹. Clopyralid use on Canada thistle with the Detectsprayer was reduced 71 to 80%, with cost savings of $44 to $50 ha⁻¹. The Detectspray system is a useful tool to effectively manage weeds in conservation fallow and reduced tillage cropping systems.