Centennial Ag Supply Company

We wanted to take some time and discuss some common issues that popped up in the 2008 growing season.  With all extreme weather we had you probably saw about every kind of deficiency possible in corn.  The following are a few tips to keep in mind for your 2009 corn crop and if you recognize any of these symptoms we can discuss how to help elevate them  for next year.

The most important thing to know when trying to identify one nutrient deficiency from the next is mobile vs. non-mobile nutrients. If a plant runs short of a mobile nutrient, it will rob that nutrient from the lower leaves. So if the lower leaves turn color first, you have a mobile nutrient deficiency. Mobile nutrients include N, P, & K. Non-mobile nutrients include sulfur and most of the micronutrients. If a plant runs short of a non-mobile nutrient, it CAN’T rob that nutrient from anywhere else in the plant. So if the upper leaves turn color first, you have a non-mobile nutrient deficiency.

• Nitrogen deficiency starts on the lower leaves first. Leaf yellowing starts at the tip and works its way up the mid-rib of the leaf. If the deficiency is severe, leaves will eventually turn brown and die.

• Phosphorus deficiency can be identified on young plants by  reddish-purple leaf tips and margins. Phosphorus is also mobile and easily Tran located in the plant, so deficiency symptoms will appear on the lower leaves first. This deficiency will usually become less noticeable in later stages of the plant’s life because phosphorus is typically more available in warmer weather.

• Potassium deficiency is first noticed as yellowing of the leaf margins (the outside edges of the leaf) beginning on the lower leaves. Potassium is also mobile in the plant, which is why you can tell how bad your plant is deficient by how far symptoms progress up the plant.

• There are also some secondary and micronutrients that may be deficient in the plant. Sulfur deficiency looks like yellowing or bleaching of the upper leaves. Zinc, manganese, boron, and iron deficiencies in corn can look like inter venial white striping on the corn leaf lengthwise.

When determining WHICH micronutrient is short, it is best  to run a tissue test. The main thing to remember with all of these deficiencies of the corn plant is you will not notice them until they are really bad. Once you see them, you have already lost yield. It is a good idea to pull some tissue samples in suspicious fields so you can tell if you have a potential deficiency problem. Sample a good area and sample a bad area. Then, compare the results. If you catch a problem in time and it is not out of control, foliar feeding can help, but it is a much better idea to take care of fertility problems ahead of time.  So if you recognized any of these symptoms we can discuss them and then we can adjust your soil fertility program for the 2009 season.