The production of concentrated nitrogen compounds from thin air is useful enough that we'll almost certainly keep doing it en masse in an electric-only future.

Mining for phosphorous and potassium fertilizers, likewise, but situationally a little different because these aren't very mobile in the groundwater column like nitrogen is, and they don't offgas back into the air like nitrogen compounds do. Quite possibly we'll be mining manure lagoons more, for CH4 and for closing the loop better on P and K.

Ag will continue at industrial scale for cereal grains, because half the population is not going back to the fields.

Within that framework, there's a lot of difference between outcomes in terms of how green we make our farms, what we grow, how we grow it. Herbicide and insecticide practices do not have to be what they are, as we witness massive overuse of things like neonics, glyphosate, and aminopyralid mostly because there's little financial reason to constrain use. We could stand to dramatically reduce the amount of cereal grain we consume, from a diet perspective, but the logistical difficulties of alternatives like more fresh fruits & vegetables will tend to increase carbon emissions. Eating less grain-fed meat and more high-protein legumes is basically a win-win from diet and climate perspectives. Returning to a less industrialized industry where livestock are raised on farms instead of on "feeding operations" seems like a fair tradeoff against something like subsidized corn-ethanol production. Attempting to encourage long-term soil stability with reduced tillage and is another goal that we might tangle with that would reduce yields; We have plenty of yield to spare in the US, so this is an option.

It is a given that bovines should be eating grass (one of the most productive plants there is with the highest calories per acre), not grain, and with the bonus that bovines or other ruminants eating grass improve the soil ecology and lessen erosion. There also isn’t any need for fertiliser inputs, or any oil/gas produced inputs at all.

Chickens can also be raised more sustainably. They don’t need to be raised 50,000 at a time, and don’t need to be fed grain. I don’t feed mine other than in winter when there is snow, and they don’t forage past an acre or so area. We produce a surplus of more chicken meat and eggs than my household can eat, and I still have enough time to work full time doing something else. (The same goes for my cows, but they take even less work and basically sustain themselves - I have not bought feed for them in two years.)

Oddly enough, I now sell my eggs for less than grocery stores charge for them. I could easily plant enough cereals and legumes for my household (about a 10,000 sq ft area or ¼ acre), but haven’t done this the last 2 years since I put my effort into vegetable gardens and livestock instead.

Part of the big myth is that we need industrial scale “farming”. We don’t. A lot more humans need to be a lot closer to producing the food they eat, though. If someone owns/maintains a lawn, they should be using it to grow food, instead of buying factory farmed food. (I give apartment dwellers a free pass, but I see large swathes of land that do nothing but grow grass and then have a lawn mower run across them.)