Agriculture in the current state is wasteful of water, but it doesn't have to be that way. Ban or limit fertilizer and make the farmers use real nature that can store rain water much better.
There’s no individual incentive to do those things, at least on a year-to-year basis which is how people make decisions. You think about this year, within the boundaries of your own property.
But the benefits are largely for the region, not the individual.
So, it need to be done by government, or it won’t be done at all (at scale).
Of course some small individual farms will do (and are doing) it on principle because it’s the right thing to do. But we can’t rely on ethics to drive behavior at the economic level.