By Dave Nanda
Windshield scouting is never a good idea, even when the crop is young. You can learn a great deal more by getting out in the field, whether it's corn or soybeans. Take your notebook with you and make legible notes. By the time you combine the crop this fall, you won't remember for sure what you saw on May 1 or June 20.
Here are some more suggestions for things to observe early in the season. We began this series yesterday. My original intent is to suggest you use these techniques on test plots, but you could apply them to field situations as well. In test plots or where you're testing a practice, you're more likely to see more differences because the entire field wasn't planted to the same hybrid or variety, or wasn't treated the same. However, the same scouting and note taking techniques still apply.
Purple color- Some corn seedlings have a purple color early in the season because of their genetics. If all your hybrids are showing purple coloration on stalks and leaves, it may be because phosphate is deficient in the soil. Consult your soil test results for the field. Or it may be caused by another factor, such as soil compaction, which is affecting uptake of phosphorus by the roots. Make a note of those fields and spots within a field so you can follow up later.
Yellow color- Anything but dark green is worth noting! If you're corn plants are showing yellowish leaves, it could be caused by nitrogen loss. If nitrogen is deficient or enough is not being taken up by the roots to satisfy the plant, yellowing will start in the mid-rib area and expand toward the leaf tip. If you're seeing this, you may want to apply nitrogen as soon as possible. If you have already applied N, you may wonder about how much of the N has been lost, and think about whether you should apply more nitrogen on that field or not.
This condition is most likely to show up if we have a wet, cool spring, which we seem to be headed toward so far. It will also depend upon when the N was applied, whether it be last fall or earlier this spring before you received considerable rain fall. Since nitrogen is so important to corn yield, you need to get this one right! (Nanda is a crops consultant and director of genetics and technology for Seed Consultants, Inc.)