Agriculture is boom-and-bust, precisely due to the unpredictability of the weather, infestations, etc. It's more predictable today than in the past, but there is still a lot of guesswork going on. There are sophisticated mechanisms in place for mitigating this, such as the futures market and insurance.

I'd wager that the "compensation" the hay farmer mentioned above is part of an insurance-type scheme. Maybe like this: http://www.washingtonpost.com/national/health-science/drough...