An "acre" is about 4047m² in modern units, so at "one sun" of 1000W/m² you would get 4.047 megawatts per acre. Multiply by the factors above, you actually 89kW/acre. A year is 8766 hours, so that's 780MWh/acre/year.

Suppose you get a PPA signed for 3 cents a kilowatt hour, US$30/MWh. That's US$23400/acre/year. But that's revenue, not profit. You can compare it to the US$1125/acre/year you give above. So what are the expenses?

The most fundamental cost here is the solar modules. 4.047MW at 50% coverage and 22% efficiency is still 445kW peak. At the current US$0.15/Wp in international markets, that's US$67000 to plant that field with panels, noticeably more than the US$675 you report to plant it with corn.

But, if you're still measuring land in acres, as if we were in the Canterbury Tales, you're probably in the US, where modules cost roughly double what they cost in the rest of the world, due to bipartisan tariffs to protect US fossil fuel interests. And the balance-of-plant costs are typically about double the cost of the modules alone. So, instead of US$67000, you're probably looking at US$300k for those 445kW (or 597 horsepower, or the power of roughly 1100 American-football running backs, if you're more comfortable with those units.)

US$23k per year from a US$300k investment is about 7% ROI, which is probably profitable but not wildly so. And if you don't have a signed PPA, you can expect that revenue to decline, as cheaper panels and power electronics drive the value of daytime generation to zero, and household units that don't need such high balance-of-plant costs reduce demand for utility-scale generation. Also, you can expect heavy industry to move to countries where solar power costs less, reducing demand.

The cost of the land isn't really significant at these investment levels.