Back before/during the Great Depression, American farmers were amazingly productive. They were so productive that the huge supply of food they produced crashed the market. The law of supply and demand tells us why: a huge glut of anything on the market will make the price fall dramatically. And when prices fall, farmers lose. And when the farmer goes broke, the only way he can make more money is by producing yet more, which gluts the market and sends prices falling further. It’s a deadly cycle.
What farmers wanted in those times was some kind of farm parity, a guarantee of worthwhile prices for their products. FDR worked this idea into his New Deal, but the only way to get it started was to destroy vast amounts of farm produce. So there we have the Depression, people starving in the streets, but to insure farm parity we had people pouring out massive quantities of milk on the ground, killing baby chickens, etc., because without creating scarcity and raising prices, more farmers would go under. (If you gave it away for free to hungry people, you would destroy your market, see?) Sure, people saw it as a terrible waste, but FDR would get on the radio and give little Economics 101 classes and people eventually understood that the farmers going broke is no good for anyone. And that’s why we have farm subsidies and sometimes pay farmers not to grow food (especially on ecologically sensitive land) to this day.
Now, I wasn’t able to see what you were linking to (looks like the story changed since you posted your question), but is there a chance that the plowing-under could have been something like this? Yes, wasting food is horrible, but farmers have to make enough to keep the farm, too.