By Harold Watters, Ohio State University Extension
It seems everyone has a “package” that gives an extra yield bump. Many of these packages contain micronutrients. In Ohio, because we generally have clay in our soil and reasonable levels of organic matter, we don’t usually see a yield impact from applying micronutrients. But should we be concerned about micronutrients?
Our soil tests are most reliable for pH, phosphorus and potassium and can work reasonably well for zinc, too. We usually use a combination of soil and tissue tests to determine micronutrient deficiencies. Soil pH can also help us know where to look for deficiencies. See your copy of the Corn, Soybean, Wheat and Alfalfa Field Guide for descriptions and pictures of nutrient deficiencies by crop.
Typically we will see deficiencies occur in small isolated areas of a field first. When these are noted, pull both a soil and a tissue sample out of the “good” area and out of the “poor” area and compare the results. Also check a recent yield map for losses in that area. Nutrient deficiencies I have seen of late are potassium from early dry conditions and occasionally sulfur — neither of these are micronutrients however.
It is interesting to note that we have two different philosophies in Ohio on nutrients. We build and maintain for the macros, but wait until we see deficiencies and apply as needed for the micros. This difference in philosophy results from the fact that we have so few micronutrient deficiencies in Ohio.
Are we short on sulfur yet? Maybe, in some very low organic matter soils, but generally probably not. In nine trials I have conducted over the past six years I have yet to see an increase in yield from the addition of sulfur, but I am doing the work again this year. I do expect as we continue to clean up our power plant emissions that we will eventually see a need for added sulfur. In the meantime, save your money, or do a little trial work of your own.
What about that other “stuff” that costs just $5 an acre. I regularly check out those advertisements, and listen to the sales pitch at farm shows but usually walk away without making a purchase. I recently had a farmer tell me about a product that was absolutely the “best ever, and guaranteed to boost yield.” I asked him why I never heard of it? Because if it’s that good, there would be 25 university tests showing how great it is… and we (the OSU Agronomic Crops Team members) would be telling everyone about it.