Even if you bought 7 years' worth of wheat, you are risking on what happens in the future. Besides loss from vermin or spoilage, the conditions in the future that affect the price can make a lot of difference in the perceived wisdom of your purchase. If there is famine, you are a genius. If the market overflows and bottoms out, you are left holding a lot of a low priced commodity.
SD
As an expereinced agrarian, he doubtless hedged his long physical position with a short future contract using the small contracts available on the Mid-America Commodity Exchange.