Why You Must Scout During the Season to Understand Yield Results

CORN ILLUSTRATED: Raw yield data doesn't mean as much if you don't know the history of the field.

Published on: Nov 18, 2013

If you want to learn lessons from this year's crop, test plots or even whole fields, you need to know more than the final yield. You need to know what happened in the field during the entire growing season, from start to finish. Otherwise, as Mark Lawson, Danville, Ind., says, you're just looking at autopsy results and trying to figure out what happened with no knowledge of what went on when the patient was alive.

Lawson is a farmer and agronomist for Syngenta. He harvests many plots each season. But he can interpret results because he watches those plots during the growing season.

Here's an example not linked to Lawson that illustrates why season-long scouting is important. An entire field of 60 acres of corn yielded 207 bushels per acre of dry corn this fall. The farmer was happy. The message would seem to be come back and do everything the same way next year, hope the weather cooperates, and harvest 207 bushels per acre again.

Blank tips: These dont look like ears from a 207 bushel per acre corn field but they are. Imagine the yield if tip kernels had not aborted soon after fertilization.
Blank tips: These don't look like ears from a 207 bushel per acre corn field but they are. Imagine the yield if tip kernels had not aborted soon after fertilization.

The truth is that some things still went wrong. Dave Nanda, director of genetics and technology for Seed Consultants, Inc., says the field could have yielded 250 bushels per acre if everything had gone right all season long. There are take-home messages for improvement from the field. You wouldn't get them just from reading average yield off the yield monitor as the combine pulled out of the field.

For one, the field showed signs of nitrogen deficiency in very early August. Tracking it down, the operator had problems with the nitrogen applicator, and applied 15 pounds per acre less than he wanted. His intended rate was already a bare-bones rate.

Second, scouting before and at harvest showed that corn borer was active throughout the season in this non-GMO corn. Some ears were falling off at harvest because larvae bored into ear shanks. Chalk up a few more bushels of yield potential that were lost to insects.

Finally, almost all ears had an inch or more of blank tips. Scouting after pollination confirmed that the kernels were fertilized and started to develop. Dry weather late, coupled with nitrogen deficiency, apparently led to kernel abortion as the plants tried to protect and fill the good kernels that were further along. Filling the tips alone could have added 40 bushels per acre.

So even if you're happy with yields this year, still think through the season as a whole. What could you have done to make the yield results even better?