FRANKLIN — Using a soil health trailer as a visual aid, Fay Benson of Cornell Cooperative Extension demonstrates why practices such as cover cropping and no-till farming are effective at preventing runoff, controlling erosion and retaining nutrients.
Benson was the afternoon guest speaker at the 2017 summer meeting the University of Vermont’s (UVM) Extension Northwest Crops and Soils Program, Friends of Northern Lake Champlain and Farmer’s Watershed Alliance hosted all day Thursday in Franklin.
Farmers, community members and state officials were invited to Tim and Martha Magnant’s Bridgeman View Farm from 10 a.m. to 2:30 p.m. to learn about and view conservation tillage practices, such as interseeding cover crops and no-till corn.
Funded by the Natural Resources Conservation Service, the solar-powered trailer has a self-contained water supply and is equipped to conduct a number of demonstrations.
This included a rain simulator which illustrates how rainfall affects five different types of soil: a corn field conventionally tilled for five years, a corn field no-tilled for three years, a buffer strip for three years, continuously grazed pasture and rotationally grazed pasture. Benson dug up a small section of each soil type from in and around Magnant’s farm.
Beneath each soil section hangs two glass jars. The jar in the front captures water that has runoff the top of the soil; the jar directly underneath captures water that has filtered through.
Benson turned on the simulator and let the heavy rain droplets fall until each soil section had received an inch of rainfall, roughly one gallon each.
He said he does this demonstration because people can see which soils retain or filter water through and which do not for themselves.
When the rainfall was complete, Benson walked the audience through the results, starting with the cover crops that had been rotationally grazed. The front jar was empty, meaning no water had run off the stop. The back jar was full of clear water, meaning the soil had successfully filtered the water. “We’d call that a success,” said Benson.
The next section was continuously grazed pasture. The front and back jars were almost evenly filled with water. “I always found that quite interesting because you think, you’ve got a cover crop here… that should give it a pretty good heads up as far as being a healthy soil,” said Benson, “but it’s the compaction that we’re seeing on this pasture (that causes the runoff.) If you don’t rest your soils, they get compacted.”
The third section of soil was collected from a buffer strip. “Now, I’m a little surprised I didn’t see more go through this one,” said Benson. But there’s another way to look at it, according to Benson. “Even though it has almost half a gallon that ran off, that means it stored half a gallon,” he said.
He had Rachel Gilker from Ben & Jerry’s Caring Dairy program explain the next section which was taken from a no-till corn field. “Well it definitely allowed a lot to absorb,” she said.
“The more organic matter you have in the soil, the more water it’ll hold,” she explained. “You add one percent organic matter in an acre, you’ll hold another 20,000-25,000 gallons of water.”
Benson said it’s important for farmers located near rivers to take note of this. “The water doesn’t go immediately into the rivers,” he said. “It takes time to get there,” which means less flooding.
Gilker added that not only does runoff strip nutrients from the soil, only to dump them into the lake and add to it’s water pollution levels, but it also strips away the top soil and “that’s your money.”
Comparing the section of no-till cornfield against the conventionally tilled cornfield, the former’s front jar had more water runoff, but the water was clearer, according to Benson. It had less soil particulates than the conventionally tilled section, meaning better filtration.
No-till, cover cropping
During the event, attendees were invited to walk around Magnant’s farm and check out one of his non-GMO, no-till, interseeded cover crop cornfields. UVM Extension is conducting multiple experiments on this 11-acre cornfield, according to Magnant.
“Tim’s been a really active partner with Extension activities for at least five years,” confirmed Jeff Sanders of UVM Extension. “One of the things we’re trying to do is figure out how to cover crop better in Vermont.”
Magnant’s field was interseeded on July 7 with a cover crop mix of annual rye, tillage radish and medium red clover, according to Sanders. Attendees were invited to walk the rows of corn to see the cover crops planted in between.
Heather Darby of UVM Extension said through an eight-year study, the program has learned that if a farmer adds cover crops to a no-till field, the yield’s rival and surpass the conventional tillage. “But without the cover crops in the no-till silage system, the yields are still far less than the conventional tillage corn,” she said.
In fact, Darby said a conventional till system with cover crops produce two tons more than a bare no-till silage field. “If you’re going to have no-till corn silage in Vermont, you better be getting a cover crop in there, otherwise you’re going to continue to see yield drags,” she advised.
“This is some of the nicest corn probably in the county and this whole farm is no-till or modified no-till,” said Sanders. “There’s no heavy tillage going on here and this corn will go up just fine against anybody’s corn. So it does work.”
“The thing is, people have to be committed to making it work, and then, they have to work through the challenges to get to the successes,” he said.
Sanders said Magnant has been doing no-till long enough to see increases in his soil’s resiliency. “It’s just a very nice image of what no-till can do,” he said, looking back at the cornfield.
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