Farm Progress

Soil chemist offers seven tips to help farmers find ways to improve their soil and their plant health.

Walt Davis 1, Editor

November 14, 2018

4 Min Read
HEALTHY SOIL, HEALTHY PLANTS: The healthier your soils are, the healthier your crops will be. But how do you know what your soil needs. A chemist offers some tips on what you should do.

Kyle Lilly, a chemist with Compass Minerals, was inspired by the book "Seven Habits of Highly Effective People" to devise his own list of "Seven Habits for Farmers to Promote Plant Nutrition," which he is now promoting to the clients he advises.

Lilly stresses that knowledge of your soil and its chemical activity is key to promoting crop health and protecting crop yields.

Here are his seven tips:

1. Be proactive. "You need to be aware of all the factors that might impact your soil health and subsequently your plant health," Lilly says.

That means being aware of soil types, what trace minerals might be needed and what type of applications of major nutrients such as nitrogen, potassium and phosphorus would work best in their operation,

2. Do soil tests. The only to know with certainty what nutrients are deficient is to conduct soil tests. Testing in the fall can provide an opportunity to apply some nutrients in the fall, especially phosphorus, potassium, zinc and manganese, Lilly says.

Those nutrients tend to be stable in the soil and will bind to soil particles meaning that a fall application will not leach out.

"The only nutrient you need to be concerned about fall application is nitrogen," Lilly says. "Especially in warmer or wetter climates, you have a greater risk that nitrogen will volatilize or be leached out."

The trace minerals, such as zinc and manganese, are important. Deficiency in zinc could cause 10 to 20 bushels per acre of yield loss because it is critical to building new roots and helping the crop stand up to cold stress. Manganese is important in cell division and chlorophyll production and is a critical factor in overall vegetative growth.

3. Determine crop removal rates. The higher your yields, the more nutrients that a growing crop has likely removed from your soil, Lilly says. The good news is that higher yields also mean higher residue, which puts some nutrients back as it breaks down.

However, that means you need to test both the soil and the residue for nutrients, so you know what to expect.

Corn residue is high in potassium and testing can tell you what nutrient rate you need, he says.

But an important piece of information is the "cation exchange capacity" of the soil which is a measure of the power of soil particles to hold onto nutrients and release them when a plant needs them.

An optimal level is 15 to 30, typically found in clay and silt loam soils. A deficient level is under 5 and applies largely to sandy soils.

"If you have very low rates, you may need to feed nutrients frequently with a small amount at planting and making most applications at V6 through tasseling," he says. "Fortunately, in the Midwest, we are largely blessed with soils with much high capacity."

4. Consider in-season tissue testing. The best way to know if the nutrients you put on or into the soil are reaching your plants is to pull tissue tests on your plants and send them into a laboratory to see if nutrient levels in the plant tissues are up to par, Lilly says.

"You can be applying nutrients such as nitrogen that, because of some micronutrient deficiency, are not being taken up by the plant," he says. "There are products that can be applied on a foliar basis to stimulate the pant to efficiently use nitrogen.

5. Determine the best source for nutrients. It isn’t always just about the nutrient, Lilly says. It is about the best way to deliver it to the plant. Compass Minerals offers a product called Wolf Tracks, a dry powder coating of micronutrients that is applied to granular nitrogen, phosphorus or potassium fertilizer to supply trace elements.

6. Check your financials. You need to consider all your inputs to make sure you are getting a return on your investment, Lilly says. Fertilizers in general are a great investment, he says. Around the world, 50% of yields are due to fertilizer.

"I would encourage growers to look at efficiencies and apply fertilizer in a way that is at the least risk for loss," he says.

He says that no-till can help sustain healthier, larger population of microbial life, but in some environments can result in too much residue buildup. Cover crops can retain and add nutrients while providing a root system that protects the soil from wind and water erosion.

"It comes back to soil testing and tissue testing so that you don’t waste money on fertilizer that you don’t need and you don’t ignore ways to add nutrients you do need," he says.

7. Continue learning. "You need to look at your numbers year to year. Look at yield results, check what you did last year and then revise your plan and continue improving what you are doing," he says.

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