John Deere released its quarterly earnings and the farm equipment giant said that crop prices will continue to rise through next year, driving farm incomes to record levels.

The biggest maker of tractors by sales and revenues, John Deere said the price of wheat, corn and soybeans have all hit their highest levels in over 30 years because of a perfect storm of factors. Deere affirmed that reduced crop yields, restrictions on exports, dwindling supplies and surging demand around the globe have converged to fuel the price rise.

The Financial Times reports that while farmers in the U.S. have benefited mightily from the boom in commodity prices, policymakers worry that rising prices could fuel food riots around the globe - much like what happened in 2008 when commodity prices experienced a similar boom.

Moreover, Deere upwardly revised its forecast for commodity prices in 2011, forecasting wheat to rise another 10 percent and soybeans to climb an additional five percent. Deere also said U.S. farm receipts could hit $359 billion in 2011, beating the previous high of $330.5 billion in 2008.

Nonetheless, the boom in commodity prices has helped Deere sell more tractors and other farm equipment, said Susan Karlix, of Deere's investor relations. "Historically, farm cash receipts for both this year and the previous one are a key driver for ag equipment sales."