WAHOO, Neb.—Farming communities that were largely insulated from the recession last year by high crop prices and other factors are now feeling the nation’s economic chill more acutely as corn, wheat and soybeans become cheaper, and land values fall.

Farmers across the Midwest and Plains states are increasingly cautious about spending on new equipment and land, and that is threatening businesses that until recently had been spared serious financial hardship.

At the John Deere dealership in Wahoo, combines and tractors farmers ordered last year with proceeds from $7 per-bushel corn are still being delivered — despite the fact that corn prices are now closer to $4 per bushel. The activity doesn’t yet reflect how frugal many farmers have become because of falling crop prices, dwindling land values and burgeoning problems in the ethanol industry.