In west central Illinois, farmer Brent Johnson expected strong corn and soybean harvests this year after a good start to the season, including even crop emergence. But as harvest begins, he says the late-summer dryness and heat are eroding potential: corn yields are down by about 20 to 30 bushels per acre compared to last year, and soybeans are off by about 8 to 15 bu/ac.

Johnson began combining corn on September 3. Two weeks into harvest, crop quality is decent-but far from last year. Fields have suffered from prolonged periods with little to no rain: some haven't seen precipitation in seven weeks, others for as long as nine months. Temperatures have also soared above 90°F (32-33°C), with record-high heat during days and elevated nighttime temperatures adding stress.

One unexpected problem: kernel weight is lighter than usual. Normally, August and September allow kernels to swell gradually, boosting bushel weight. This year, with a quicker finish to the growing season, kernels didn't develop fully. "We're just racing to the finish line," Johnson says.

Earlier planted corn (in May) may be among the hardest hit. Traditionally his best yielding corn, this year those plots may lag due to less favorable conditions late in the season. Soybeans are also showing irregular maturation: green pods and non-uniform maturity increase moisture in harvested samples and reduce overall yield.

On the flip side, disease pressure remains lower than might be expected, because dryness has limited fungal outbreaks. Johnson notes that while southern rust is being discussed elsewhere (especially in wetter states), his area has largely avoided severe disease damage.

Broader climatological data supports his observations. The U.S. Drought Monitor classifies large parts of southern and central Illinois as being in moderate to severe drought (D1-D2), with much of the region abnormally dry (D0). Soil moisture has dropped sharply; river and stream levels are declining; and forecasts suggest dry conditions and above-normal temperatures will persist through mid-September.

These conditions raise serious concerns for commodity prices, input costs, and crop insurance. With yields below expectations, farmers may see reduced revenue, while costs for inputs like fertilizer and seed continue to rise. Insurance claims could increase if drought damage qualifies under loss thresholds.

While national yield forecasts (such as USDA's) are still fairly strong, many analysts warn that late-season weather could force downward revisions. Illinois, in particular, may see its projected high yields trimmed if the drought worsens or moisture doesn't arrive soon.