U.S. farmers are embracing an alternative means of turning sunlight into revenue during a sharp downturn in crop prices: solar power.

Solar panels are being installed across the Farm Belt for personal and external use on land where growers are struggling to make ends meet. The tit-for-tat tariffs applied by the U.S. and China to each other’s goods have cut demand for American crops. Futures prices for corn, soybeans and wheat are all trading around their lowest levels since 2010. Making matters worse, record spring rainfall...