At nearly any field day, there is likely to be a presentation on the benefits of abandoning conventional tillage.
Erosion, water retention and soil health are the main talking points when discussing a transition to limited or no-till practices. However, conventional tillage is still an important part of many farms in the Midwest.
Whether it’s for weed control or incorporating manure, Richard Cruse, director of the Iowa Water Center and agronomy professor at Iowa State University, said tillage has benefits for plenty of operations.
“It could be a moldboard plow or a chisel plow system that does some mixing,” Cruse said. “It could be a farming system that has feedlot manure applied to the surface, where there is value in not leaving it on the soil surface, or systems where they are trying to avoid herbicide use.”
He said in many cases, tillage is also used to kill overwintering cover crops, where the intent isn’t to disturb the soil.
One instance where full tillage works optimally is on some organic farms.
Paul Mugge, a farmer in Sutherland, Iowa, utilizes conventional tillage on his farm, but with his three-year rotation of organic corn, organic soybeans and a small grain or legume, he only needs to till every three years. That tillage comes between the small grain/legume year and the corn.
“It’s very easy to kill with a disk and field cultivator,” Mugge said. “I make a lot of trips, but those trips are fast and light. I’m trying to lose as little soil as possible.”
Mugge said conventional tillage is the best option for weed control on his farm. Being an organic farmer, he doesn’t have access to the herbicides that other farmers may use. He also said it fits in his farm’s rotation. He said they’ve come to this schedule after years of trial and error, particularly after becoming organic 20 years ago.
“That’s why I have to cultivate everything,” he said. “I rotate tillage systems (each year), I rotate fall crops, I rotate cover crops, and I think that’s all important.”
Mugge said something he wants to continue doing is removing passes across his land. Going full tillage every three years is a start, but he said organic farmers sometimes catch flack for using too much energy with their tillage. On average, he said, organic farms will use less fossil fuels than conventional farms.
“It’s mainly because of nitrogen fertilizer,” he said. “Fossil fuel energy goes to making anhydrous ammonia, and I don’t use any of that. I use my red clover and animal manure. From a fossil fuel part of the equation, I’m doing OK.”
He noted the other part of the debate is resource conservation, which is why Mugge opts to limit tillage to his every-three year standard. He said tillage makes the soil vulnerable to erosion, but using other conservation methods can help combat the losses. He credits his high soil organic matter to using cover crops and other practices.
“I have narrow prairie strips and most of my farm is on a contour, so I don’t lose a lot a lot of soil,” Mugge said. “I’m sure I lose some — everybody does — but I try to limit that as much as possible.”
Cruse said most tillage is going to reduce density of the soil — a trade-off. However, doing it in a way such as on Mugge’s farm often helps counter some of the soil health concerns.
“If you are going to incorporate alfalfa or clover, the increased soil erosion that can follow — depending on rainfall — is countered by the soil conservation you get during the years in which you have small grains growing in that rotation,” Cruse said.
“To really see the effect, you have to see the soil erosion potential over the entire time frame of the different crops that are used in the rotation.”
He said there has been a bigger trend of farmers moving toward less tillage. He said when he was first working in agronomy, the idea was the blacker the soil was, the better the farmer operator was perceived to be. Now, that mindset has changed overall.
“The overall trend is to leave more residue on the soil surface,” Cruse said. “That, and reduce energy expenditure in terms of the tillage operation.”