Sustainability practices to build soil tilth need to be profitable

STOCKTON, Ill. — Soil tilth building practices should be considered offensive management tools.

“Cover crops have been pushed as defensive tools against erosion, water quality problems or impeding regulations,” said Mitchell Hora, a seventh-generation farmer from southeast Iowa.

“But instead of playing defense with cover crops, they should be part of the fertilizer, pesticide, herbicide, moisture and temperature management program and now part of a carbon or sustainability program, as well,” said Hora during the Nutrient Stewardship Field Day.

The Hora family started using no-till in 1978.

“We have been using cover crops since 2013,” the farmer said about the 700-acre operation.

“If I want to get the nutrient cycling and weed suppression out of my cover crop, I’ve got to prioritize it and get it done correctly and evenly across the field,” he said. “And it has to return dollars back to my bottom line.”

One of the metrics the farmers have been watching is soil infiltration.

“Across the country, the average water infiltration rate is one-quarter of an inch of rainfall per hour,” Hora said.

“On our farm, we can infiltrate 4 inches of rainfall in under five minutes,” he said. “We’re down to 50% coverage rate on our crop insurance and we haven’t replanted in four years.”

Corn on the Iowa farm is planted green into cereal rye.

“We plant green on every acre of our farm,” Hora said.

Nitrogen is split applied and part of the program is an anhydrous application.

“We put our cover crop in the fall into the soybean stubble and knife in anhydrous,” Hora said. “In the spring, we plant directly on top of that and terminate our cereal rye after planting.”

A little bit of nitrogen is put on with the planter in-furrow.

“It is a humic-based product that has some micronutrients in it,” Hora said. “When we’re burning down our cover crop, we add 32% UAN — you don’t want too much because you won’t get a good kill, and you don’t want not enough, then you won’t get a good benefit.”

Hora plants all the soybeans first.

“Our corn is planted during the last week of April to the first week of May,” Hora said.

“We have put no lime on our farm for the last 12 years and no potash in eight years,” he said. “We have cut nitrogen by one-third, cut fungicide by 50% and we don’t use seed treatments or insecticides.”

When developing sustainable practices, Hora said, it is important to be patient.

“We really started cutting back on those things in year four to five, not right away,” he said. “Sustainability doesn’t matter if the farm isn’t economically sustainable — it’s not just yield, it’s profit that matters.”

The most abundant element in a corn crop is carbon, Hora said.

“God put the stomata on the under side of the plant for a reason because the plant takes in carbon dioxide through the stomata,” he said.

“The microbes respire out carbon dioxide, the plant captures it, converts it into simple sugars and pumps up to 70% of the simple sugars back into the soil through the roots to feed the microbes.”

The microbes then eat, reproduce and die to become plant available nutrients for the next year’s crop.

“We’ve quantified this with the Haney soil health test,” Hora said. “One of the most important components of that test is soil respiration CO2-C which is an indicator of biological activity.”

The average number is 50 to 60 parts per million.

“The best score I’ve seen was over 1,000 and I like to see that number in the 150 to 250 range,” Hora said.

“The more food we get for the microbes, the more microbes will respond to cycle nutrients, build soil health and organic matter so we can cut back on inputs,” he said.

Hora planted soybeans during the week of April 10. This is the fifth year that he is harvesting the rye as a relay crop.

“Instead of terminating the rye, we bring the combine out and harvest the rye in July over the soybeans,” Hora said.

“In a dry year like this we only made 18 to 26 bushel rye,” he said. “We plant full season soybeans with no fertilizer, seed treatments, insecticide or inoculant.”

The benefit is “crazy amounts” of nodulation on the soybeans, Hora said.

“We have up to 200 nitrogen credits for corn the following year,” he said. “By stimulating diversity, we’ve got living roots and no disturbance and that’s giving us a lot of benefits the following year.”

In addition to his work on the family farm, Hora is also the founder of Continuum Ag.

“It is a software company that helps farmers map out soil health, document farm practices and monetize what they are doing for sustainability initiatives,” he said. “We are in 43 states and 20 countries and this whole movement has taken off like crazy.”

For more information about Continuum Ag, call 319-461-9056 or visit continuum.ag.