Crusts and emerging corn …not a good combination!

This unfortunate mixture adds one more setback to corn in an already tough year. Eighteen percent of Iowa’s corn was emerged as of last Sunday, 18 May. On average, corn is at 57% emerged this time of year. Since the last NASS report, we have had much more corn emerge and more is continuing to emerge. But unfortunately, some of the corn planted in April and early-May is struggling to surface.

Wet planting conditions coupled with fine soil texture, intensive tillage over the row, and heavy rains after planting result in a pulverizing of the soil surface due to a weakening of the soil structure. Subsequent drying results in soil crust formation. We have posted several photos of crusted corn on the Image Gallery in our website.

We have also just posted an article on ICM news relative to corn emergence issues.

Several possibilities exist with crusted corn:

• Delayed or no emergence. Corn seedlings will make a heroic effort to reach the surface as shown in some of the photos but at times to no avail.
• Reduced plant populations.
• Variable plant emergence.
• Rootless corn.

Reduced yield as a result of any or all of the above factors.

What can producers do?

• Assess their fields. Count emerged plants. Ascertain whether the seedlings struggling to emerge will reach the soil surface.
• Use tools developed to determine yield potential and the likelihood of the need for a replant. Many are listed under Planting on our website.
• Rotary hoeing may be an option for some, although rare situations. Be aware that rotary hoeing often reduces plant stands 5 to 10%; this becomes even more given certain field conditions. Be certain to check seedling survival and effectiveness of the hoeing operation before proceeding too far into a field.

What can we hope for from this point forward in 2008?

• A gentle rain with slow drying conditions afterwards (as I write this Iowa is experiencing thunderstorms. These may help problem fields in several areas.)
• A stellar year from here on out in terms of temperatures and water!

SOURCE: ISU’s Roger Elmore

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