One measure by which conventional agriculture likes to judge itself, the output per man hour, or, put another way, the percentage of the population directly engaged in crop production, is seriously misleading, because it in effect presents the extraction of human attention from the process as a measure of success. They aren't focusing on attention, of course, other than to find ways to spread it thinner, over a larger area of land, because it's expensive.
In this effort to spread human involvement over more area, the first thing out the window is any operation which can't be performed linearly, like plowing, by moving through the field along rows, and the main casualty of this limitation is intensive intercropping. You can mix two or maybe even three crops together in alternate rows in the same field, but not twenty, like you might in your garden; it's just too cumbersome. It's really more convenient to plant just one crop at a time, and as we move upscale, from oxen to tractors pulling implements a hundred feet wide, that convenience becomes a matter of practical necessity, and even minor lack of uniformity in the land itself becomes an annoyance. The result is flattened fields planted to a single crop, as far as the eye can see, and travelers on any highway passing through it hurrying along because it's so boring.
Attention isn't the only thing being extracted in this scenario, so is soil fertility. Tillage, something we've taken for granted for ten thousand years, means unnatural aeration of the soil, which in turn means rapid oxidation of its organic content. Single-cropping means long months of exposure to wind with minimal cover or none at all. The net effect is called "desertification".
So what does all this have to do with robots, and how might they be part of a solution rather than simply making the problem worse?
The simplest definition of a robot is a machine that responds to its environment. The nature of that response might seem trivial in many cases, as in determining the exact position of the tip of a welding rod in relation to the parts being welded and adjusting accordingly, but it's a start, and, as robotic technology advances, more sophisticated responses become possible.
It's unfortunate that the same word, when applied to a human, means exactly the opposite. For this reason I generally refer to "robotics" rather than "robots" to make it more clear that I'm talking about technology in which the acquisition of information and its use in determining the behavior of the machine are essential characteristics, in many cases the most important ones.
It's also unfortunate that "robot" overlaps so much with "android", which refers to human-form robots that mimic human behavior or behave in ways similar to humans. I'm not talking about androids.
What I envision are machines that are designed to move gingerly through thick growth, performing simple operations like planting seeds and pulling weeds, while creating a minimum of disturbance. They might be supported on long, spider-like legs that only ever put weight on particular, gravel-covered spots, or they might be suspended from overhead rails or cables, but they would be engaged in paying detailed attention to what was happening on the ground, including the presence of animals as well as the slow-paced growth of plants, intervening only occasionally as compared with the amount of information they would be processing, although to the casual observer it might look like they were awfully busy.
These machines would have only a modest rate of energy consumption, and might easily get what they need from solar panels, with any excess going to charge batteries that would allow them to continue to operate into the night, and at least keep watch 24/7.
I can only envision such machines, of course, because they don't yet exist.