I'm not going to provide a source, but my understanding is that one square meter can provide roughly 1 KW of electricity at noon on the equator. Looks like that's about 4MW per acre. Five acres for the "traditional" family farm. I bet where I live that irradiation equals 1MW per acre, and of course it varies seasonally. Sounds ridiculous, until you've tried to water any sizable amount of square footage, and contemplated the heat energy required to evaporate all that water which doesn't go into the plants and isn't runoff.