Could be possible that some weed adapts to grow through the bush or something, what i like specially about this is using legumes as both cover and fertilizer, which is something permaculture uses a lot too. Also it's reminiscent of how corn was traditionally grown, with beans as nitrogen fixing and squash as ground cover. But on the long run, my bet is on diversity instead of monocrops.

I've been researching a lot of plants and weeds lately, and quite frequently I am being reminded that there are many plants that are toxic to cows and horses, and so part of your job is to make sure your pastures are free of these plants.

One of the appeals then of broad spectrum herbicides that you scorch the earth and plant what you want in the space. And despite some very loud protestations of horse owners, people who try to garden with horse manure have to contend with herbicides.

Mechanical pest/weed management is still a very powerful tool. And maybe some day we can have robots do that for us, but we don't have to wait that long to get much of the benefit.

In order to kill a weed, you first have to see the weed. Rather than putting all of this onto a drone, there's plenty of utility to be gained by having a system that looks for these plants and geotags them. Then a centralized identification system (possible, the farmer's eyeballs) can filter down the false positives and they can send someone out to dispatch the weeds by hand, and/or adjust their graze rotation patterns to reduce exposure.

And something organic gardeners learn intimately is that every weed has intervals where they are most expensive to deal with. Seedlings may be too labor intensive. Blooming weeds are priority 1. But depending on soil profile, some weeds are easier to kill once their stalks and roots have become more robust - strong enough that you can grab the stalk and pull.

So on any given day you may be aware of a hundred weeds, but only twenty of them are on the priority queue.