Plant and Soil Health: Micro and Secondary Nutrients on Soybeans: What’s the story?

Recently, I read an article published by a well-respected group of academic researchers on the effects of micronutrients applied to soybeans. Their results showed no increase in yield and inconsistent increases in plant tissue and grain micronutrient content on plots treated with one product or combination of products.

I have no doubt, on the plots they tested, the results they published are correct. Many times in small, replicated plots very little if any yield changes are achieved regardless of what is being tested. There can be several reasons for this. Most of the time these plots are planted on “prime” locations where pH, soil fertility, drainage and other factors that can affect yield are taken out of the equation. Great attention to detail is given to these plots and no corners are cut, no short cuts taken. However, this ain’t how it works in the real world of soybean production.

Throughout the growing season we deal with saturated soils, poor pH management, low CEC, low organic matter and soil test levels, and other factors like herbicide stress, insect stress, and environmental stress. In on-farm trials across the Midwest, done in normal and often stress-production environments, what I and others have found is that we can greatly impact yield with applications of micronutrients and secondary nutrients.

Zinc, boron, manganese and iron, along with sulfur and magnesium, have shown a positive impact on yield as well as an excellent positive ROI when used in the right situations. I don’t intend to demean the findings of this team, but to simply point out that it is foolish to start “making production plans on your farm without doing some testing on your own.” With the data collection capabilities most growers have today this is an easy way to test new products and practices on YOUR farm.

Remember, Liebig’s law of the minimum says that yield is limited by the lowest limiting factor. That means your pH, N P, and K levels can be perfect, but if you have a Zn deficiency you can keep that crop from reaching maximum economic yield. I would encourage you to find a trusted and experienced source for good information on the benefits, for your geography, of a soil or foliar micronutrient application.

Also, talk to your seedsman and see if he has information on the varieties you plant and how they react to applications of these nutrients. These are all just pieces to a puzzle; make sure you have the correct pieces for your farm. If you are able to do your testing, by all means do so. But each of you has a trusted advisor who is there to help you succeed, not just sell you products. He will have experiences beyond what you see on your own farm.