[jqm]

This is cool but I have to disagree with this phrase from the article.... "Given the scale of farming today, treating weeds chemically is really the only practical way for humans to keep them under control".

It's the easiest way to keep weeds under control but not the only practical way. (Source: I worked for the weed science department (yes, they had one at my school) while at university.)

Here are some other methods for reducing weeds:

1) Before planting, till and water the field causing weeds to germinate. Then harrow the field killing all the weeds. Do this multiple times if needed.

2) Good old fashioned cultivation as was done before the herbicide period. (The article on the robot was posted a few days ago and in response I posted the below... it has a lot of pictured of weed control devices which may be interesting to someone working on robotic weed control....https://archive.org/stream/SteelInTheField/Steel%20in%20the%...)

3) Crop spacing. Space crops so they out-compete the weeds (this is already usually done).

4) Keep fields clean. Keep the ditch-rows clean. Don't let weeds go to seed. After a period of time the bank of weed seeds in the soil is reduced and there are less weeds to control

I know herbicides are faster and cheaper (if we don't consider externalized costs). But they aren't the only "practical" way to eliminate weeds. It does take good management and more effort to eliminate or reduce herbicide use though. I personally think it's very worth it. Oh, and I'm excited about robotics. I don't know about this device, but I do think field robotics is the future.

[jqm]

There is another approach to weed control. Don't do anything. Let weeds come up if they want to.

I remember a crusty old guy in Florida showing me his watermelon field that was full of weeds. I said something about it and he said the weeds actually shaded the watermelons keeping them from sunburning and he had no intention of removing them. I don't know if this is necessarily true or if he just didn't feel like doing anything about it but apparently he didn't think the weeds were causing economic harm and there were a lot of watermelons in spite of the weeds.

[arjie]

Funny. Masanobu Fukuoka in One Straw Revolution argues for a similar approach in orchard maintenance, if I recall correctly: allowing all sorts of plants to grow below the trees and provide ground cover.

[garrettgrimsley]

When growing plants such as carrots, as mentioned in the parent article, the crops are competing with the weeds for space, sunlight, and nutrients. In the orchard this is not an issue, and the ground cover can be beneficial to the crop.

[jqm]

In carrots (which are densely planted like four rows to a bed) weeds sometimes do come up in the bed between plants. They usually aren't many because the carrot tops get so dense they smother most weeds out. You can't cultivate those weeds with a tractor (without destroying the carrots) and I don't think they have a roundup resistant carrot. So it's people walking the rows with hoes from what I've seen, or some other herbicide carrots are immune too. The device in the article might be especially good for situations like this.

[arjie]

Oh, absolutely. One Straw Revolution isn't a weeds-are-good book. It's a description of less intrusive methods to maintain crop health.

For rice plantations, he does try to ensure weeds don't grow. I don't remember the exact methods advocated, but I believe it was placing straw all over the ground, and for some crop he grew clover in the downtime between harvest season and growing season, I think. I don't recall too much, though.