Currently, most farmers and custom applicators spray agrichemicals on their fields behind slow-moving tractors. The process is clunky, labor intensive, time sensitive and even dangerous at times. Admittedly, this common system works, but it is costly and leads to overuse of agrichemicals. Overuse of chemicals leads to resistance and makes it hard to kill superweeds. Farmers would like to apply agrichemicals at a variable rate and spot spray, but existing technology makes it hard to accomplish this.