Corn Up and Trying to Shake Off Yellow Color

CROP WATCH 2014: Corn emerged in about 10 days or fewer despite cool weather.

Published on: May 26, 2014

The Crop Watch '14 field in the Eastern Corn Belt is up and running – well, almost. Leaves still show some yellow discoloration, but as the temperature climbs, the yellow seems to be disappearing.

Until proven otherwise, the most likely cause was cool weather. Highs in the 50s and lows in the high 30s after the corn emerged that persisted for several days didn't make for great growing conditions.

Overall, the stand seems uniform, both in spacing and even emergence. Is it perfect? No, but no stand is perfect. But it does appear it would be a standard deviation of 2.0 or less if you counted distance between plants in several locations.

Bob Nielsen, Purdue University corn Extension specialist, usually tells people that if you can achieve a standard deviation of 2.0 or less, then yield should not be affected by plant spacing. Standard deviation goes up if you have lots of doubles, triples and skips. If it goes up too much than it's possible yield could be affected due to poor spacing and competition.

CROP WATCH 2014: Corn emerged in about 10 days or fewer despite cool weather.
CROP WATCH 2014: Corn emerged in about 10 days or fewer despite cool weather.

Related: Check Fields To See How Well Planter Worked

Correctly adjusted planters today tend to produce near picket-fence stands. That's what it takes to produce a stand that can fall at or under the 2.0 standard deviation. The deviation refers to distance from the desired space between plants.

Doing it this early in the season most of the variation in spacing between plants is due to planter errors. If you wait and do it later, it could be due to insect damage or other factors that take out plants. If you find a gap now, without digging you don't know if the planter didn't drop a seed there or if it was a seed that didn't germinate.

Up and ready: The yellow color is beginning to disappear from these corn leaves. This shot from the Crop Watch 14 field overall shows a uniform stand of corn for spacing and emergence.
Up and ready: The yellow color is beginning to disappear from these corn leaves. This shot from the Crop Watch '14 field overall shows a uniform stand of corn for spacing and emergence.

Typically, germination is around 95% for normal conditions. Germination this year was under cool conditions.


From the corn hybrid you select to the seeding rate and row width you choose, every decision you make influences the size and scope for corn yields. Download our FREE report: Maximizing Your Corn Yield.