If we're willing to accept higher labor intensiveness, there's plenty of very realistic farming techniques that could be reintroduced. For example:
- Off-season cover crops like legumes, etc both can fix nitrogen and out-compete weeds.
- Intercropping, where different crops are planted in proximity (like alternating rows). This is less susceptible to pests and disease than monocultures, and the plants can be chosen to mutually enhance each other's fitness.
In general, a lot of these techniques also give a healthier ecosystem, with more pollinators and predators of pests. The yields can be excellent and sustainable, but it is more labor. However, there's plenty of bullshit jobs[0] out there, and many people in them might find this kind of work more meaningful. I think a future society would do well to allocate labor with these goals in mind.