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Saving the soil

Cover crop use rising in Iowa fields

Published: Tuesday, Aug. 19, 2014 11:37 a.m. CST • Updated: Tuesday, Aug. 19, 2014 11:49 a.m. CST
Caption
(Mike Mendenhall/Daily News)
Heartland Co-op Seed Specialist Steve Uhe presents a handful of cereal rye — a cover crop — in the organization's warehouse in Prairie City. Cover crops are rising in prevalence in Iowa, as they have been proven to stop soil erosion, mitigate farm runoff and maintain soil nutrients in the winter season.

PRAIRIE CITY — In the warehouse at Heartland Co-op in Prairie City, Seed Specialist Steve Uhe opened a large vine sack on a wooden pallet. He cupped his hands and scooped cereal rye seed out of the bag.

“There are more and more people using it,” he said. “As in any farming endeavor there are the early adapters and the people that sit back. But I know every farmer is talking about it.”

Uhe said Heartland Coop customers and Jasper County farmers in general seem to be part of the early adopters in Iowa. Cover crop has been used in the eastern part of the U.S. for over a decade. It has been shown to stop soil erosion and act as a filter, catching farm runoff before it silts into nearby waterways.

Cover crops like cereal rye began to trend in Iowa four to five years ago when water quality and soil pH levels began to pose a problem for farmers and city watertreatment plants alike.

“We were having real heavy rains and people were having erosion issues,” Uhe said. “So people were investigating ways to really slow that down.”

On top of erosion control, Uhe said farmers have seen additional benefits to cover crops in the area of weed control – suppressing winter annuals. Cover crops have also helped soil structure in Iowa farm fields, building organic matter and trapping nutrients into the soil over the winter months when fields would normally see a loss of nutrient content.

Uhe said cover crops sequester nitrogen — a key nutrient in corn production— hold the fertilizer and release it into the soil as the cover crop breaks down in the spring. As cash crop is harvested, there is nothing to retain that moisture and nutrient causing farm runoff and degrading local water quality. The cover crop holds that nutrient, keeping it for the next season’s cash crop.

“The nice thing is the corn comes along a few months later and the nitrogen is there for it to use,” he said.

Some research has shown that cover crops can also help breakup the dry, thick layer of soil below the soil called the hardpan. This dry layer of subsurface soil can be caused by increased acidity in the earth. Uhe said if a farmer plants a rye, turnip or radish for three to five years, the added cover crop can reduce that pH level by allowing water down into the hardpan and increase cash crop yield.

At a conference in Des Moines, Uhe has spoken with farmers from Illinois and Indiana who have planted cover crops for 10-12 years who claim to experienced 20-25 bushel per acre increases in cash crop yield as a direct result.

Gordon Wassenaar is a corn and soybean farmer south of Prairie City. This fall will be his fourth season using cover crops. Last year he planted 1,200 acres of cereal rye following the fall harvest. He said he did not invest in the crops increased yield, but as a long-term investment to stop soil erosion on his land.

“I didn’t do this expecting an overnight yield,” he said. “That’s the one thing I’m certain of is that it has halted erosion.”

Along with its benefits, cover crops are an added expense for farmers. Uhe said to plant the recommended 50-80 pounds per acre, cereal rye can cost $17-23 per acre depending on market prices.

The Iowa Department of Agriculture in conjunction with the USDA has financial assistance programs available to farmers who are first-time cover crop planters. New growers are eligible for up to $25 per acre. IDA Communication Director Dustin Vande Hoef said $2.8 million was available for distribution from the USDA last year. The aid was dispersed within two weeks of becoming available. This year there was a decrease in funding for the assistance program, with only $1.4 million available. This was allotted in one week.

According to IDA data, more than 400,000 acres of Iowa farm land contained cover crop after the cash crop harvest, but this is only a fraction of the 23 million acres used for row crop planting in the state.

Wassenaar has been able to plant the cover crops without government assistance. Mike Gannon farms corn and soy near Newton and also works with Wassenaar. He said one of the challenges for cover crop users is the short planting window following the harvest. At times, planters can have only days to get the cover crop into the ground before the first freeze. Wassenaar said it’s almost necessary to plant his cereal rye as he harvests his corn and soy.

“The logistics are the hardest part,” Gannon said. “You’re already under a time crunch getting your cash crop harvested. So, getting a cover crop seeded in the fall and being timely about it is crucial. When you have to begin seeding, you literally have only days left in the growing season to get something started.”

Wassenaar and Gannon have been looking at different methods of cover crop planting, including planting before the harvest when they are not as crunched for time. They are also looking at other added benefits for the soil. The farmers explained the importance for planters to understand the specific needs and soil contents of their fields in the coming decades. This knowledge will determine the type of cover crop used.

Gannon said certain cover crops have been shown to fight disease, mitigate weeds and add targeted nutrients.

“I think learning how soil works and the biology of the soil is going to be really important over the next 20 or 30 years,” he said. “Cover crops are kind of a first step in that.”

“I think this is going to be the trend,” Wassenaar said. “If you go long-term and restore the organic matter and increase the amount of water the soil can hold, that can be extremely critical.”

Contact News Editor Mike Mendenhall at (515) 674-3591 or mmendenhall@shawmedia.com

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