When I was scouting fields north of Huron, South Dakota, I scouted one of the most unique fields I have ever seen.  The height of the corn ranged from 12 inches to about 60 inches tall and the color was from yellow to dark green.  I would bet most of us have seen this in low spots or hilltops, but this didn’t matter where it was in the field.  After pulling soil and tissue samples, we found out it was a nutrient deficiency.  The farmer spread cattle manure on the field.  Some spots were extremely high in the nutrient, while other spots had none.  When the general soil samples were pulled in the spring, the high concentration and low concentration spots mixed together, indicating no need to add the nutrient. 

If you have come across something like this, you might have a nutrient deficiency.  If you are curious, there is a way to test the plants themselves for nutrient content.  I would like to thank Steve Sutera, Agronomy Extension Educator in Bon Homme County, for the following information.

Plant analysis is one way of confirming if the symptoms of plants that do not look quite right are nutrient related.  It may indicate a nutrient deficiency or toxicity problem.  A plant analysis is most helpful if affected plants are sampled along with some of the unaffected plants.  These plants should come from adjacent areas growing under similar conditions.  This allows the nutrient analysis to be compared.

Soil samples from the poor and good areas can also help with interpretation.   A note of where in the field and conditions under which the poor plants are growing is helpful as well.

If the corn is less than 12 inches tall you need to send in 20-25 whole plants (roots and all).  If the corn is 12 inches to pretassel, your sample should have 25-30 of the uppermost fully developed leaves.  Corn that is tasseling to silk initiation should have 25-30 of the leaves that are just below and opposite the ear.  Soybean samples should contain 40-50 plants or 40-50 of the uppermost fully developed trifoliate leaves if the plants are early flowering to setting pods.

Fresh plants are a must.  If it will not be possible to collect and send the samples the same day, then the samples need to be air dried before they are sent.

Soybean Rust

South 2 FEU Agronomy Educators Steve Sutera, Connie Strunk, and Matt Bernau are actively scouting for Asian Soybean Rust in a Sentinel Plot near you.  This is being done in cooperation with the USDA Sentinel Plot program as a part of the USDA National Plant Diagnostic Network.  The Sentinel Plot program is the first line of defense against Asian Soybean Rust and also allows us the opportunity to identify and monitor any other diseases and insects in soybeans. 

Hopefully we will not encounter Asian Soybean Rust this year, but if it does reach South Dakota, we are ready.  As with all insects and diseases, scouting is your best plan.  Scouting is important because it allows you to protect your investment, the growing crops.  If you would like more information on Soybean Rust or on scouting fields, feel free to stop by my office or give me a call at (605) 356-2321.