A lot of farmland goes to hay fields too, which isnt just for cattle and aren't devoid of biodiversity. For example, barn owls use hay fields to hunt hence why they tend to nest in and around barns(how they got their name). Many farmers encourage them to live and nest on their property.

Hay often gets sold locally to people who own horses, goats, chickens, alpacas etc. Small, local rural economies depend on this sort of thing. Plus apiaries are often set up next to hay fields to promote pollination for certain types of grass hays, which is then sold as local honey at farmers markets.

Not saying solar can't coexist with what I've said above because it absolutely can and I'd love to see more of it. Just this idea that farmland doesnt support wildlife isnt true. Deer, barn owls, rabbits, mice, snakes all use the hay fields before and after cutting. Plus the fields used for hay aren't good for much else. Too rocky, hilly, or nothing else will grow.

Source - I've lived in a rural farm town for most of my life and grew up playing in hay fields. Lots of critters live in there.