What your test plot can tell you

If you were able to plant plots despite the tough spring, it’s important to get the most value out of it. I suggest taking notes, beginning soon after planting. Actually, you can take notes on any field, whether you planted a test plot or not.

Here are my suggestions:

Record emergence: Record the date of emergence when 50% of the plants in each hybrid are out of the ground. Some hybrids tend to have an early establishment period. That’s a good thing.

Study vigor: You can pick up differences in early vigor in hybrids only if you have various hybrids to compare to and walk plots. You will find distinct differences in vigor among hybrids and varieties.

Key Points

Taking notes makes sense in a test plot or in a regular field.

What yellow plants mean depends on where yellowing is located.

Purpling of plants can have several causes.

Observe color: Some hybrids have purple seedlings due to genetics. If all hybrids have purple stalks and leaves, it may be a phosphate deficiency. Consult soil test results. Or it could be caused by soil compaction, which affects uptake of phosphorus by roots. Note those fields to follow up later.

Yellow color: Yellowish leaves could be a sign of nitrogen loss. If N is deficient or enough is not taken up by roots, yellowing starts in the midrib area and expands toward the leaf tip. If so, apply N as soon as possible. If you’ve already applied N, you may wonder about N loss. Think about if you should apply more N. However, if yellowing and browning are around lower leaf edges, it may be potash deficiency.

Check for diseases: Are any signs of susceptibility to disease showing up? Diseases appearing early include Stewart’s wilt in corn, caused by a bacterium carried by flea beetles. In soybeans, watch for phytophthora. It’s more likely to show up in low, poorly drained spots.

Another rot in soybeans, if it stays cool and wet, is rhizoctonia. It attacks susceptible varieties. It forms brick-red lesions near the base of the seedlings.

Stay tuned for more helpful hints in observing plots as the season progresses. You can take notes on a notebook in the field, then file them to a computer later.

There are sophisticated scouting tools available that allow you to electronically record notes and, through GPS, reference them to where you are in the field. However, some of these devices retail at $1,400 to $1,800 or higher, plus software.

A pocket notebook and a pencil are a much more economical way of observing plots. Take along a copy of the Purdue University Corn and Soybean Field Guide, 2012 edition, as a reference. Check out www.ces.purdue.edu/new.

Another helpful guide with graphic pictures to help identify disease and insect problems is the Corn, Soybean, Wheat and Alfalfa Field Guide issued by Ohio State University. It features spiral binding, and is known as Bulletin 827. Order it at: estore.osu-extension.org.

Nanda is an agronomic crops consultant and director of genetics and technology at Seed Consultants Inc. Contact him at Nanda@
, or call 317-910-9876.


Take notes early: Note signs of disease showing up on young corn.

This article published in the June, 2011 edition of INDIANA PRAIRIE FARMER.

All rights reserved. Copyright Farm Progress Cos. 2011.