by Deborah Jeanne Sergeant
Maintaining soil balance may positively affect yield, quality and the environment, according to panelists recently assembled by Ohio Agricultural Research and Development Center participating in a moderated call-in conference, “Soil Balancing: What do the Numbers Say About Its Effects on Soils, Crops, Weeds and Farms?” Matthew Kleinhenz, vegetable production specialist at Ohio State, moderated.
Can the ideal balance of nutrients, calcium, magnesium and potassium achieve the most outstanding results? The panelists included Steve Culman, Ohio State soil fertility specialist; Doug Jackson-Smith, Ohio State Environment and Natural Resources; Bob Jones Jr. with the Chef’s Garden; Josh McGrath with University of Kentucky; and Joe Nester of Nester Ag LLC.
“Soil balancing is a philosophy whose detractors can be counted,” Kleinhenz said. “Soil balancing includes practice that can be tested alone or with other factors and can be quantified and measured.”
Nester, who works as a crop consultant, said he has noticed a shift in the number of farms looking to improve their soil balancing.
“Some farms are 70 percent clay,” he said. “We struggled with no-till for quite some time.”
Paying attention to soil additives, drainage and nutrient uptake usually makes a big difference with clay. Nester said nearly all of the 4 million acres of forage, grain and wheat his firm manages use one or more practices of soil balancing.
“I get together with consultants regularly,” Nester said. “I know there are a lot who also pay attention to the soil balancing principles.”
In addition to balancing the chemical aspects of soil, Nester said physical and biological aspects “have more impact than N, P and K. The key in working with heavier clay soil is to minimize stress and the duration of stress on the crops.”
Water causes most of this stress, including too much early in the season, too little for the middle of the season and too much in August. To combat these issues, “we want better water filtration rates,” Nester said.
He admitted that for many years, he tried to simply manage soil pH.
“What we’re trying to do is increase water filtration,” Nester said. “It draws air into the soil behind the water. We’re promoting the biological side which promotes the physical side. We get earlier planting. With weather challenges, we get less compaction. We can take heavy equipment out there and not damage the soil. I’ve read in books and theories but it doesn’t fit everywhere in my market area or everywhere in a field. The farmer realizes this. I’ve never had any farm where we’re managing soils say ‘I don’t want to do this anymore.’”
Culman said in the past “science has ‘pooh-poohed’ claims about soil balancing.”
“There has been past research and there have been probably a couple dozen studies over the past 20 years,” he said. “In the ‘70s, ‘80s and ‘90s, all those trials were focused on yield with few other parameters. The research itself in terms of what’s published has shown that it’s not a profitable way to manage soil.”
Jones, who manages 400 acres (125 in vegetables and the rest in forage or cover crops), said that success in farming his sandy and clay soil relies upon viewing soil balancing as a three-legged stool: physical structure, chemistry and biology.
“We believe very strongly that they’re inter-connected with both positive and negative connections,” Jones said.
By keeping the soil in balance, he’s achieved better saturation numbers. But how to keep soil in balance can be tricky for producers, since many theories about soil balance exist. Since soil balancing takes a long time, it’s important to stay with one theory.
“Pick a horse in the race and stick with that horse,” he said, referring to deciding on how to balance soil.
Kleinhenz said a listener emailed a question about soil balancing. He had never worried about it as an organic farmer and experienced well above average yield. “Are there any principles that make soil balancing valid?” he asked.
Jackson-Smith answered, “We understand the role that calcium amendment can be used to affect soil structure, especially with improper irrigation management. We know that on some of the science, the jury is still out, like on the role of calcium versus magnesium.
“Why would thousands of farmers practice this if it’s bunk?” Kleinhenz added.
He asked the panelists what they have been hearing from people about soil balancing and its applicability.
Jackson-Smith said his project focuses on documenting and trying to get numbers on soil balancing and people’s experiences when using soil balancing.
“There’s an interesting puzzle behind the whole process,” he said. “The science has very little support that through calcium or calcium/magnesium alone you can get consistent results. Either everyone has the wrong idea or the science has to address it in a way that replicates their practice. This project has been trying to bridge that gap.”
He has interviewed 1,600 organic corn growers from several states, asking about ratios specified, if they used calcium amendments and if they consider themselves soil balancers. Half said they were; however, only 20 percent responded with specific soil balancing practices.
“There was no evidence they were using the approach,” Jackson-Smith said.
Results such as these challenge researchers to figure out what’s going on in fields that the scientific community has been unable to reproduce.
McGrath, as a soil fertility expert, said he relies more on soil testing data to understand what’s happening in the field.
“Alternative ag markets like organic producers are looking for something different because they’re managing differently, perhaps,” McGrath said. He supports a balanced approach instead of a yield-based approach.
“Farmers tend to associate weeds with water and flooding events,” Jackson-Smith said. “We’ve seen that thread continue to reflect imbalances in the field.”
Culman said changes in the soil take time. “As scientists, we recognize the limitations in our approaches,” he said.
A study lasting only four to five years may not be long enough to see results for some approaches.
“We have been looking at biological parameters and soil physical structure,” Culman said. “This summer, we measured filtration rates systematically using penetrometers to measure soil compaction. At a site with heavy clay, at the site where we’re using magnesium sulfate, we found a three times lower level of infiltration and increased penetration resistance. Our gypsum at that site wasn’t particularly unbalanced to begin with. Adding more calcium, we didn’t see any measurable differences. We’re cautiously optimistic that these results can’t be replicated.”