"Zinc is the most Widespread Micronutrient
Deficiency in the Corn Belt"

FJ. You were with TVA for a long time weren't you ?
Yes. for almost 31 years.

FJ. What were your responsibilities?
I conducted research and development mainly on micronutrients and other fertilizers.

FJ. Did you do much of your research in greenhouses?
Yes. In addition to field research, many of my published papers are concerned with greenhouse research. We worked with university extension and research people to obtain in-field results where fertilizers are used.

FJ: For a grower interested in making sure he doesn't have a micronutrient deficiency, how reliable are current micronutrient soils tests?
I'm confident of the tests. Various tests have been calibrated for certain types of soils in different regions of the country. The important thing is to send a soil sample to a regional lab to assure the correct procedure is used for that region. How you sample is particularly important for micronutrients, because you need to get a representative sample of the field in question. After you've obtained the sample, you've got to be very careful that you don't contaminate the sample with other micronutrients that are also at very low levels in the soil.

FJ. Where do you sample?
Most of the time in the root zone, which is generally four to eight inches deep. Once you take deep samples, and include those with shallow samples, you're going to end up with a lower value because the level of available micronutrient decreases quite quickly below the root zone.

FJ: What depth are we talking for sampling ?
It depends on fertilizer placement. If we take a representative sample, then it should he in the root zone. But if you're not tilling, the levels are going to again decrease because the previously applied micronutrients won't be down towards the bottom of that 12-inch zone.

FJ. What micronutrients should be added to starters?
Zinc and manganese especially. Those are the main two.

FJ. What are the most common micronutrient deficiencies in the Corn Belt?
Zinc is the most widespread. Manganese would be next, then boron. Following this, we have iron and copper. Mainly, I'd be concerned with zinc, manganese, and boron for crops such as corn, soybeans, alfalfa, sugar beets, and vegetables.

FJ: What micronutrients can be added to fluid fertilizers?
Well, zinc is widely used with fluids. There is usually no problem applying one to two percent zinc in starters. The only precaution is there's a possible effect on seed germination with starter fertilizers handed close to the seed row.

FJ: Should micronutrients he broadcast or banded?
Broadcasting is common. With zinc there's quite a difference between band and broadcast in terms of effectiveness. Comparing broadcast to starter, the general rule is that you put on double the amount of zinc if it's broadcast. Some say the ratio should be even higher

FJ. Is there much tissue testing going on with micronutrients?
Not as much as there used to be. Tissue tests should be used to verify your current fertilization program. They reflect the nutrient status at the time you sample. So it's a matter of using it as a checkpoint. It's also a great way to help verify nutrient deficiencies. Some growers have a standard practice of making these tests as a check on their fertility program.