Released: March 27, 2007

Act Now for Healthy Corn Stand Later

MANHATTAN, Kan. - Doing everything they can to ensure a good corn stand will be especially important to producers this year, according to Kansas State University agronomist Kraig Roozeboom.

With current tight seed supplies for many corn hybrids, producers may have a hard time getting seed if they need to replant for any reason, said Roozeboom, who is the cropping systems specialist with K-State Research and Extension.

He provided these key factors for establishing and maintaining a good stand:

* Seedbed conditions. Don’t be in a hurry this year. Wait until soil temperatures at the 2-inch depth are consistently above 55 degrees at midday, especially if planting early in the recommended time frame. Planting into a wet seedbed can cause sidewall compaction and inhibit root growth into the surrounding soil. Cool, wet soils favor seed rots and seedling diseases.

But, planting into a dry or cloddy seedbed can result in uneven emergence. In some situations, it also may delay emergence long enough for rodents or birds to seriously deplete the potential stand.

* Seed treatments. Consider using seed treated with both a fungicide and a broad-spectrum insecticide such as Cruiser or Poncho, particularly if you have a history of seedling or early-season insect pests.

* Planter maintenance. Make sure your planter is properly maintained and adjusted. Corn seed must be planted at the proper depth, with good seed-soil contact and good closure of the seed furrow. This is particularly important in no-till situations, which have greater amounts of residue and a firmer seedbed.

* Starter fertilizer. If possible, avoid placing starter fertilizer in direct contact with the seed. Starter fertilizer applied in a band to the side of the seed or dribbled on the soil surface at planting time will probably help early corn growth. On the other hand, if you are placing starter fertilizer with the seed, be sure to use less than 10 lbs per acre of N and K combined.

* Field scouting. Once the corn emerges and the stand is established, scout fields closely for early-season insect problems. Seedling corn can come back from a rapid defoliation that occurs early. But repeated defoliations or a persistent insect infestation (such as flea beetles) can eventually weaken or destroy a stand.

* Weed control. Preplant or planting-time herbicides should provide adequate control during the critical stand-establishment phase. However, early scouting is important for weeds, as well, to maintain the stand and to protect potential yield. Keep an eye on fields to make sure that rainfall was adequate to incorporate and activate the herbicide and that the product is performing as expected. Don’t wait too long if follow-up treatments seem necessary.

* Watch the weather – rainfall. On some soils, one of the more common causes of stand failure is soil crusting, caused by pounding rains soon after planting. This problem can also relate to making necessary planter adjustments and to planting into a good seedbed, because challenging conditions after planting will magnify errors in those areas.

* Watch the weather – late spring freeze. A hard freeze after corn has emerged is potential problem Kansas producers face nearly every year. A hard freeze often burns back the foliage on seedlings or young plants, sometimes to the ground.

But, so long as the corn is not yet at the V6 (six-leaf collar) stage, a spring freeze rarely causes death of the entire plant. From the time of emergence through the V5 stage (the first two to three weeks after emergence), the growing point of corn is below the soil surface and protected from freeze injury. For plants at the V3-V5 stages of growth, a freeze may cause some corn development problems as new leaves try to push through the dead leaf tissue, but stand and yield losses typically are minimal.

On the other hand, a hard freeze at the V6 or later stages can severely injure a stand and make replanting necessary. Avoiding the extremes of the recommended planting window for your area and paying attention to the extended weather forecast should minimize the risk of the stand loss caused by late freezes, as well as the yield loss typically associated with late planting dates.

More information on corn production is available at all county and district K-State Research and Extension offices and on the Extension Web site: http://www.oznet.ksu.edu.

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K-State Research and Extension is a short name for the Kansas State University Agricultural Experiment Station and Cooperative Extension Service, a program designed to generate and distribute useful knowledge for the well-being of Kansans. Supported by county, state, federal and private funds, the program has county Extension offices, experiment fields, area Extension offices and regional research centers statewide. Its headquarters is on the K-State campus, Manhattan.

Story by:
Mary Lou Peter-Blecha
mlpeter@oznet.ksu.edu
K-State Research& Extension News