A NO-TILL CHAMPION
AGRONOMIST PUTS NO-TILL TO THE TEST IN POORLY DRAINED SOILS.
When agronomist Jason Cavadini began as assistant superintendent of the University of Wisconsin Marshfield Agricultural Research Station five years ago, he got glazed looks from farmers at his mention of trying no-till at the station. No-till would never work, they said.
“I knew they had more experience with the soil than I did, and so I knew there was good reason for what they believed,” he says. “But we’re a research station. If we just demonstrate the status quo without trying something else, then what’s our purpose for being here?”
Cavadini had grown up on a no-till farm in western Wisconsin, and he’d studied no-till and cover crops as a graduate student. The soil conditions he found at Marshfield, in the central part of the state, threw him a curve ball, causing him to consider local farmers’ bias against no-till.
“The soil here is wet – poorly drained,” he says. “We have 8 to 12 inches of silt loam soil at the surface, and below that it changes to dense clay.”
The poorly drained soils combined with a short growing season have historically caused farmers to till the soil to promote drying and warming of the seedbed. Without it, the thinking is that yields would suffer. During his first year at the station, Cavadini followed suit.
“I just did what I was told everyone else did,” he says. “That whole first year, I was just trying to learn what kind of a beast we were dealing with in terms of soil. By the end of that year,
I could understand why farmers have historically farmed the way they have.”
Nevertheless, Cavadini pressed on with no-till. His second year at the station, he no-till seeded his first crop of corn. Now, four seasons later, he has solid proof that no-till works in poorly drained soils.
“I’m fully convinced that no-till is working for us,” he says. “The more we get into it, the more other farmers are trying it and making it work. We’ve even started a farmer-to-farmer group in our area so farmers can share their no-till experiences.”
Cavadini’s starting point for no-till on the research station was ground that had been in alfalfa for three years. In a region rich in dairy farms and alfalfa fields, it’s a starting point he recommends for area farmers just starting out with no-till.
“In terms of stabilized soil conditions, fields that have been in alfalfa already have a three-year head start,” he says. “By contrast, fields that have been tilled multiple passes each year have soil with no structure. The soil can’t hold up on its own. Tillage leads to more tillage, and it can be hard to break that cycle of tillage without first introducing a perennial crop.”
The nitrogen that alfalfa fixes in the soil is another reason Cavadini recommends it as a starting point for first-time no-tillers. “Alfalfa is the safest place to start because of the nitrogen credits alfalfa leaves,” he says. “You can often no-till corn into alfalfa without applying any nitrogen and still get respectable yields.”
Cavadini did apply some nitrogen to his first corn crop no-tilled into alfalfa ground. “We were surprised by the results of that first corn crop,” he says. “The corn looked better than we expected, and yields were no less than they were before.
“The biggest shock was
how the soil responded,” he adds. With its underpinning of stabilized alfalfa ground, the no-till fields in one season began to express greater trafficability.
“One of the biggest reasons we are promoting no-till is because it lets us get in and out of fields with heavy equipment without getting stuck or leaving deep ruts that damage the surface and necessitate tillage,” he says.
After that first corn crop, he experimented with a rotational sequence including soybeans. He planted triticale as a cover crop after harvesting corn for silage. He harvested the triticale for haylage the following spring.
“Behind that, we planted a late-season variety of soybeans,” he says. “We call it a trit-chop soy system, and we found it to increase profitability when we considered the additional value of the forage. It provides a way for farmers to double-crop in a northern climate.”
In the main, Cavadini’s flexible crop sequence behind corn includes cover crops and perennials, like grasses and alfalfa. These provide forage for the research station’s dairy herd, while conserving soil and preventing runoff.
Triticale is Cavadini’s cover crop of choice.
“Our short growing season gives only a small window of opportunity for growing a cover crop, and so we tend to stick with small grains,” he says. “Like cereal rye, we can plant triticale after harvesting corn silage. We then harvest the triticale for haylage the following spring. Triticale is about as resilient as cereal rye, and as it matures, it declines in forage quality more slowly than rye.”
Cavadini has had success no-tilling alfalfa into triticale in spring before harvesting it for haylage.
In just four seasons of notill, Cavadini has seen soil quality improve. Soil aggregates have become more stable, and water infiltration has increased. Because of the improved drainage and soil structure, he suggests farmers consider no-till as a more cost-effective alternative to installing drain tile.
“We’ve also seen decreases in runoff carrying sediment and phosphorus,” he says. “That’s important, because in our area, we have significant soil erosion during spring melt. Some nitrate can run off. Because most soils have had applications of manure, phosphorous is the primary nutrient leaving the field. As a result, waterways throughout the state are high in phosphorous, creating algae blooms. We’re seeing an increasing need for farmers to implement conservation practices to keep sediments from leaving the fields.”
While Cavadini continues to champion no-till as a workable practice for his region’s poorly drained soils, he says it’s not the end-all for soil and water conservation.
“No-till is just one piece of the puzzle,” he says.
For that reason, he also demonstrates complementary conservation practices such as growing cover crops and perennials, and grazing livestock.
“Perennial crops are the foundation of grazing enterprises,” he says. “We need manure in the equation to feed the soil biology, keeping the biology vibrant and building soils that can hold water. The grazing of livestock applies manure with little soil disturbance and in amounts that are broadly dispersed and, thus, readily cycled by soil biology.
“We’re trying to get farmers to think in terms of soil quality as much as they think in terms of production,” he says.