RELATIVE COSTS OF A WEED-ACTIVATED VERSUS CONVENTIONAL SPRAYER IN NORTHERN GREAT-PLAINS FALLOW

Detectspray(TM) weed-activated sprayer (WAS) technology enables individual nozzles on a sprayer to turn on and off in response to the presence of green vegetation. WAS operated full season at two fallow sites in North Dakota reduced POST herbicide requirement 47 to 88%. Full-season WAS applied as needed at West Fargo reduced cost to the farmer by only 13% compared with broadcast application with a farmer-owned sprayer and assuming free labor. Winds of 8 to 16 km/h apparently moved spray off target, thereby necessitating retreatment and increasing the relative costs of WAS at Fargo. The percentage of sample quadrats having greater than 3% vegetative cover correlated positively (r = 0.78 to 0.80) with percentage reduction in spray volume achieved by WAS.