The 2024 growing season was somewhat unusual in Illinois, with overall conditions good enough to produce record-high corn and soybean yields.
The September estimate of corn yield in Illinois is 222 bushels per acre, down 3 bushels from the August estimate. Soybean yield is projected to be 65 bushels per acre, 1 bushel less than the August estimate.
These declines may reflect the increasing dryness in the state over the past weeks.
With early-planted corn and soybean at or near maturity, dryness will affect mostly late-planted crops. High temperatures and low rainfall over the next week could further diminish yields of late-planted crops, including double-crop soybeans.
Although crop condition ratings have remained high since June, we continue to hear concerns about the 2024 crop, with advice to keep scouting and to take notes so problems spotted can be corrected next year.
Some of the issues that have come up over recent weeks are presented as questions below with commentary.
Q: Is lodging in corn a serious concern this fall?
While there has been a lot of rain in places this year, there has been little damage from high winds and hail across the state.
Above-normal rainfall in many areas in July produced rapid corn growth and good growing conditions continued into August with outstanding canopy color in most fields.
Today’s hybrids build stalk strength by depositing lignin in the stalk rind. Stalks strengthened like this remain supportive even if soil dries and leaves lose their green color before maturity and even if ears are heavy. Stalk strength is probably as high now as it has ever been as the crop matures.
Although very high wind speeds could still break stalks, nothing in the forecast calls for such conditions.
Stalk strength could be an issue in areas where dryness persisted until mid-July and in late-planted fields where dryness caused loss of leaf color before maturity. In general, though, if stalks are not easy to break by pushing on them, they will likely hold up well until harvest.
Q: Does having corn leaves turn yellow as the crop nears maturity mean the field did not get enough nitrogen?
Although river nitrate levels showed that some fall-applied N likely left fields following heavy rainfall last spring, most N deficiency in 2024 resulted from problems with N uptake, not from inadequate N in the soil.
Standing water wasn’t widespread in 2024, but there was some in late May and some during wet periods in July, which may have showed up as N deficiency later in the season.
Some fields showed yellowing of lower leaves during the dry period in June, but July rainfall restored leaf color of the important leaves above and below the ear.
If canopy color was good in early August, we can be confident that loss of color beginning in late August was from dry soil conditions.
When dry soils restrict water uptake, N uptake is also low. Water and N from near the roots gets depleted, then uptake of both decline as soils dry.
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