Above-normal temperatures in mid-September helped the 2019 corn and soybean crop move closer to reaching maturity.

As we entered September, there was a great deal of concern about crop maturity because of the very late planting dates in many areas of the Upper Midwest, as well as in the Eastern Corn Belt. Even though the warmer weather has helped ease the crop maturity issues, there are still plenty of concerns remaining.

At the University of Minnesota Research and Outreach Center at Waseca, the week of Sept. 12-18 had an average daily temperature of 67.4 degrees, which is 5.8 degrees above normal. The growing degree unit (GDU) accumulation during the week was 122.8 GDUs, which is 38% above normal. As of Sept. 18, a total of 2,279 GDUs had been accumulated at Waseca since May 1, which is about 5 percent below normal and is more than 390 GDUs behind last year's GDUs.

There are still some major concerns with crop development and maturity, especially in southwest Minnesota, northwest Iowa and eastern South Dakota, where corn and soybeans were planted up to four weeks later than normal.

Based on the Sept. 15 USDA Crop Report, it was estimated that 59% of the corn crop in Minnesota had reached the dent stage, normal is 88%. For most commonly grown corn hybrids, under normal growing conditions, it takes approximately three to four weeks from the early dent stage until the corn reaches physiological maturity. It takes about two weeks for corn to reach maturity once the corn reaches the "hard or full dent" stage.

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Corn is considered safe from a killing frost once the corn reaches physiological maturity, which is when the corn kernel reaches the "black layer" stage. When the corn reaches "black layer," its moisture is usually 28% to 32&. Ideally, corn should be at 15% or 16% kernel moisture for safe storage in a grain bin.

So even beyond the corn reaching maturity in the coming weeks, some nice weather conditions will be required to allow for natural dry-down of the corn in the field. It is likely that a high percentage of the corn crop will be stored until next spring and summer.

There are also many acres of later-planted soybeans in portions of the Upper Midwest which will also require favorable conditions in the next few weeks in order to reach maturity before the first killing frost.

Soybeans normally require about two weeks to reach maturity once the leaves start turning color. Based on the Sept. 15 USDA Crop Report, only 47% of the soybeans in Minnesota were turning color, compared to a normal rate of 77%.

Southern Minnesota usually has its first frost during the first two weeks of October. 

There will likely be some additional crop loss, along with potential delays in the harvest, in the areas that were most impacted by recent heavy rains. Corn and soybean fields near any river, stream or creek, as well as other low-lying, poorly drained fields, were under water following those rains. In many cases, fields in these same areas had been damaged or were not planted this year.

Most farmers in southwest Minnesota, northwest Iowa and eastern South Dakota are now dealing with saturated soils, which could delay harvesting.

The immediate impact of the wet field conditions has been on dairy and beef producers who are trying to harvest corn silage. Corn development is at the right stage for high quality silage. In the hardest hit areas, it may take a week or longer of dry conditions for fields to be fit to resume silage harvest.

The crop damage and potential harvest problems are especially difficult for farmers who are facing very tight profit margins. Farmers in many portions of southern Minnesota, northern Iowa and eastern South Dakota were already looking at reduced crop yield potential because of poor growing conditions early in the growing season. Now, many are in a wait-and-see mode, hoping  the yields on the remaining acres are strong enough to offset the losses of acres that could not be planted.

Crop insurance

Farmers with crop losses need to contact their crop insurance agent prior to harvesting to make sure the losses are reported and verified. Producers also need to keep good yield records, and follow crop insurance verification procedures. Crop insurance indemnity payments will vary from farm-to-farm, depending on the type of insurance and the level of coverage that was purchased, as well as the final 2019 corn and soybean yields.

The current lower price levels for corn and soybeans increases the likelihood of crop insurance payments for producers with Revenue Protection (RP) crop insurance policies.

Farmers should contact their crop insurance agent for more details.