Knowing not much about anything, but watching, I see domestic and foreign crop yields vary with wars in and around food-value producing countries, local weather conditions during the crop year and politics to name a few of the major factors. Sometimes these variables have little to do with production levels and pricing of commodities in world wide agriculture.
The rest of the crop years can have enormously fluctuating production and prices. Individual producers have no power over the weather and minuscule control over their crop year conditions during political upheaval or war. Maybe not so true in the United States, but elsewhere these factors can stress and strain farm families terribly and in a variety of ways. In the United States, we have mechanisms to deal with the fore-mentioned underlying factors. I am thinking of a related forum topic to post in the near future.