Build Soil Health to Boost Plant Health
When you’ve got soil challenges, you’ve got farming challenges. Just ask Bill Banken, who farms near Appleton, Minnesota, an area known for high-magnesium soil. These soils tend to form hard crusts, making them difficult to till. High-magnesium soils also lock up valuable crop nutrients.
“You can keep putting on fertilizer, but it just gets tied up in these soils,” said Banken, a third-generation family farmer who raises corn and soybeans. “Too much magnesium also makes the soil more ‘sticky,’ so it doesn’t crumble like good-quality soil.”
An experienced no-till farmer, Banken noted that it’s also getting harder to get crop residue to break down properly in the field without tillage. “I know there are nutrients in that residue and in the soil, if we can just unlock them.”
Science shows Banken is right. There are 40,000 pounds of potassium per acre in just the top six inches of many Midwestern soils, according to the Regenerative Agriculture podcast episode “The Fallacy of Mainstream Potassium and Nitrogen Fertilization.” When the plant roots reach the lower subsoil levels, they find large quantities of potassium that they extract with the biological functions of the root system, according to podcast guest Dr. Richard Mulvaney, a University of Illinois soil fertility scientist.
In addition, there are high levels of soluble potassium carbonate in crop residue. The residue from 200 bu/A corn contains 190 pounds of potassium, along with 80 pounds of nitrogen, 30 pounds of phosphorus, 16 pounds of sulfur, 35 pounds of calcium, 25 pounds of magnesium and an abundance of carbon. “There’s a tremendous amount of nutrients we’re not utilizing if we don’t break down residue properly,” said Dennis Klockenga, a crops specialist with ProfitProAG.
The more carbon, the better the soil holds together
“When residue is improperly managed, it can do more harm than good. Before it finally rots, it often harbors harmful microbes,” Klockenga said
Contrast this with residue that breaks down efficiently, putting nutrients and carbon back into the soil. Carbon enhances soil structure and improves the soil’s water-holding capacity, which can help drought-proof your crop.
“Carbon is also a food source for beneficial microbes. It enables the production of glomalin, the substance that holds soil particles together,” Klockenga said. “This helps control soil erosion and protects soil from the explosive power of raindrops during a heavy rain. The more carbon you have, the better the soil holds together.”
Put biology back into the soil
How do you get this carbon from crop residue back in the soil, while controlling or eliminating tillage? It’s a challenge, due to today’s seed genetics.
Stalks produced by modern Bt corn hybrids are more like tree trunks than cornstalks. “It’s important to put the power of biology to work,” said Klockenga, who recommends MeltDown from ProfitProAG. This blend of beneficial bacteria and fungi helps break down lignin in the stalks. “The microbes and fungi poke holes in the stalks as they digest lignin and cellulose,” Klockenga said. “This allows Mother Nature to break down the residue.”
ProfitProAG offers MeltDown in a premix that includes a fish-based, liquid fertilizer (Pacific Gro) with fungi to accelerate residue breakdown. Banken has used MeltDown with good success.
“I can tell where we sprayed it and where we didn’t apply it,” Banken said. “On the areas that were sprayed with MeltDown, you can tell that the inside of the stalks are a lot softer. It still takes time to break down the residue, but MeltDown works.”
MeltDown, combined with the fist fertilizer costs about $13 an acre. “When you consider all the nutrients you unlock when the microbes break down residue properly, it pays for itself,” Banken said.
Cover crops are another solution to help build healthier soil. “Oats raise soil phosphorus levels, which leads to more phosphate uptake,” Klockenga said. “Plants feed the soil, and the soil feeds the plants. That’s why you want to have plants growing in your fields throughout the year. There’s still some biological activity out there, even in the winter.”
Not only do cover crops control erosion from water, wind and snow, but they help feed the soil’s microbial system. “Think back to the days when there were a wide variety of prairie plants growing on the land,” Klockenga said. “The more diversity you have in your cover crop mix, the more diversity you’ll feed into the soil.”
Banken is adding cover crops to his farming operation. He plans to seed annual rye into corn at the V6 growth stage. He trusts Klockenga to help him learn practical, proven ways to improve soil health and plant health. “My goal is to improve my soil, not only for today, but for years to come,” said Banken, whose son Cody wants to farm.
“Sustainability has an ecological component and an economic component,” Banken added. “As fertilizer prices rise, I’m hoping that we can cut our fertilizer bill by putting biology back in the soil. The more you can build soil health and plant health, the less need you have for chemicals and commercial fertilizer.”