Given the scale of farming today, treating weeds chemically is really the only practical way for humans to keep them under control, because you can use tractors or airplanes to cover large areas in a short amount of time. But all of those necessarily deadly (to weeds) chemicals then get on the plants we don’t want to kill (because we want to eat them), as well as getting washed into the soil. The most organic and eco-friendly way of dealing with weeds is the old-fashioned way: physically removing them. “Physical removal” can mean pulling weeds out completely, but that involves both grasping the weed and doing something with it. A better solution is to just smash it way down into the ground, which is faster, easier, and something a robot can do excellently: