Cover crops discussed at field day
By Janet Kubat Willette
Date Modified: 11/22/2013 11:36 AM
RUSHFORD, Minn. — David Larson didn't expect to be ankle-deep in radishes in early November, but that's the hand Mother Nature dealt him.
Larson, who farms with his wife, Sue, south of Rushford, had expected to plant corn for grain in the field now green with radishes.
A June 23 flood covered the field five feet deep in water. He needed to do something to break up the soil compaction after the flood and had heard about radishes.
He planted radishes on the field on Aug. 8, hiring an airflow seeder to plant the radishes and winter rye at five pounds per acre.
Larson intends to put his beef cattle into the radishes to graze this fall. They already have grazed another field also planted to radishes. It took about three days for the cattle to take to eating them, he said.
On Nov. 6, a group of about 25 gathered in Larson's field to talk about cover crops. The Land Stewardship Project hosted the multi-species cover crop field day.
Extension educator Jill Sackett said University of Minnesota Extension has been working on cover crops since 2009, when it received a Sustainable Agriculture Research and Education Program grant.
Cover crops are defined as a non-cash crop grown between two cash crops.
Sackett ticked off a list of benefits of planting cover crops during the field day:
• Keep soil in the field.
• Nutrient cycling.
• Decrease nitrogen loss because plants are using it.
• Decrease phosphorus loss because there is less soil erosion.
• Improved soil biology.
• Increased soil organic matter.
A field day participant wanted to know if cover crops increased the number of bad worms in the soil. Sackett hesitated to answer, saying there is no specific research on this topic.
Extension started doing research on cover crops about the same time producers started using them.
There also are drawbacks, Sackett said. Questions exist about the available nitrogen. She recommends soil tests be done in the spring to see how much nitrogen is available to the crop.
Now, interest in cover crops is growing. Some see value in cover crops to protect soil from erosion when annual crops aren't growing. Others see potential to break up insect cycles.
This year, several farmers in southeast Minnesota planted cover crops on land they were unable to plant to corn or soybeans because of prevented planting. Some planted crops they could harvest after Nov. 1; others planted crops merely to meet requirements.
Farmers in Burleigh, N.D., have been doing cover crop research on their own and they report more benefits to the soil when a cover crop cocktail is planted. They like to use 10 species at a time.
Bonnie Haugen and her son, Olaf, operate a rotational grazing dairy near Canton. They have diversified their cattle's diets by adding turnips, winter wheat, winter rye, BMR sorghum and BMR grazing corn.
They have to be careful the cows don't eat too many turnips, or it will flavor the milk, Olaf said. The cows are pastured on 1.5 acres for 12 hours and then off the field for 12 hours.
The cows weren't too sure about the turnips on the first day, but by the second day, they were chowing down, he said, and soon, they were pulling the turnips out of the ground and eating them.
The turnips give a milk production boost of three to four pounds.
The grazing corn doesn't form an ear for grain, and it's not a vigorous seed, he said, but it only takes 60 days from planting for it to be four to five feet tall and ready to graze.
Winter wheat or winter rye planted in early October will be grazed at least once in the spring. He was able to graze one area four times this year because of regrowth.
Dean Thomas, grazing management specialist with the Fillmore Soil and Water Conservation District, said it's important to wait five to seven days between terminating winter wheat or winter rye and planting.