Machine vision guided cultivation in lettuce and celery

Integrated weed management in lettuce requires the use of cultural weed control, hand weeding, cultivation, and herbicides for the economical control of weeds. If more weeds can be removed with an efficient cultivation, then there will be fewer weeds for hand weeding crews to remove. Machine vision guided cultivation can improve the efficiency of cultivation and reduce the use of expensive hand weeding. In 2007 and 2008 four trials were conducted on romaine lettuce and two trials were conducted on celery to test if the machine vision guided cultivator tools or directed herbicide applications could be used to improve hand weeding efficiency. In the lettuce trials three different cultivation tools and two directed post-emergent herbicide treatments were tested, both with and without pronamide applied pre-emergent at 1.34 kg/ha. The cultivator tools included in the comparison were: sweep knives, Bezzerides (torsion weeders), and coulters with sweep knives. The post-emergent directed herbicides included pelargonic acid at 3, 6 and 9% v/v and carfentrazone applied at 37 g ai/ha in 2007 trials 1 and 2 and at 10 g ai/ha in 2008 trials 3 and 4. Data gathered were the number of marketable lettuce heads, weed densities prior to and after cultivation and herbicide applications, hand thinning and weeding times. Lettuce yields were similar among treatments, but differences were found in levels of weed control and amount of labor required. The treatments that consistently had high levels of weed control along with low labor requirements included the knives, Bezzerides, and carfentrazone. Pelargonic acid was found to provide the same level of weed control as the cultivator tools when used at the highest concentration. The pre-emergent application of pronamide was required to reduce hand thinning times. The celery trials compared the levels of weed control, hand weeding times, and yield between mechanical cultivation with sweep knives treatments and a directed herbicide application treatment of pelargonic acid at 3, 6 and 9% v/v. Data gathered were marketable yield, weed densities prior to and after cultivation and herbicide applications, and hand-weeding times. In celery, there was little difference between directed sprays of pelargonic acid and mechanical cultivation in terms of weed control, hand weeding time, or yield. This means that mechanical cultivation and directed herbicide applications have the same success rates when used with the RoboCrop(c) in celery.