If you've been driving by some area fields recently and have been stumped by an unusual looking cover crop, it might be a field of white radish.
Most picture a radish as a small, round root enjoyed from the summer garden, but area farmers are beginning to use the white radish as a cover crop, and it's nothing like the radish enjoyed from gardens.
"It's a trend that's just getting started here," said Howard Person, Pennington County Extension Agent.
Unlike its distant cousin, the white radish produces a long tuber that can reach more than a foot in length and several inches in diameter. It's tap roots can grow several feet deep, so the radish bores a good-sized hole into the soil.
Kathy Fillmore, Pennington County NRCS district conservationist, said they are promoting the use of it through their Conservation Stewardship Program as a "green manure" crop. They call it that because it builds up the soil when it decomposes. It has several advantages, but one which is attracting attention is its ability to break up hardpan, which is a dense layer of compacted soil beneath the topsoil layer.
Person said the crop has several advantages. Because of the length of the white radish, it is believed to carry nutrients up from lower in the soil, and because it's so wide and deep, it reduces soil compaction and improves water flow. Person said it also tolerates cold well and will not freeze until temperatures reach 25 degrees. But one of the biggest advantages is that in the spring it quickly turns to mush and disappears. It tends to stink for a few days when it is decomposing, but Person said because it decomposes quickly, farmers can plant that spring, and all that organic matter enriches the soil and releases nitrogen.
Fillmore agreed saying because it grows so deep, it reduces the necessity of deep tilling.
Fillmore said it hasn't been grown very much in this part of Minnesota, but the comments she has received from farmers who have used it have been very positive. She has heard that it has increased yield in their next crop, lowered input costs (fertilizer), built back the structure of the soil, and produced healthier crops. She added that she’s studied the research, but would like to hear more from farmers who have used the crop.
Person said the use of the white radish or tillage radish is more popular in southern Minnesota. Out East, he said it has also become a forage crop for cattle.
No one is aware of any pests or diseases being spread from the white radish. Research on the white radish indicates that it actually suppresses weed development and can reduce nematode populations, such as roundworms or threadworms.
Research also indicates that because it reduces or suppresses weeds and builds up soil health, it has lowered input costs for farmers who use it as a cover crop. Radishes, like other cover crops, will stabilize the soil and prevent erosion.
Practical use
Gary Novak heard about the white radish and decided to try it this summer. He planted it in a field west of St. Hilaire where the soil was compacted. Novak said he may have planted it a little early because he thought it got out of hand. He said it grew quickly. He said part of the radish sticks out of the ground about four inches and it goes down two to four feet.
Novak said he isn't the first person in the area to have planted the white radish. He said he got the idea from Mishawn Homme, who works at the Farmers Union Fertilizer Dept. in Goodridge.
Homme said they had one area farmer use it last year to break up the compaction in a field and he said it worked really well. She said some more farmers used it this year and they are hopeful.
Homme said it's something that's planted in July or August and they just let it grow. She added that because it's something that can be planted in July and August, it's something that farmers can also use for prevented planted options.
Prevented planting is a failure to plant an insured crop by the final planting date as designated in the insurance policy. Usually, the prevented planting situation is caused by adverse weather.
Fillmore said it can be used in prevented planting situations, but it depends on the soil type. Usually, a cocktail mix of plants is recommended, but she said the white radish is a good investment because of what it adds to the soil.
The white radish is a class of plant called Brassicas, which includes the radish, forage turnip, canola and mustard. These plants tend to decompose quickly in the spring and because they decompose quickly, nitrogen is available earlier for the growing season.
Fillmore said she has also heard that when it decomposes in the spring, it smells, adding that it's probably not something to plant near a home.
In news reports from Ohio, fire departments were getting calls to investigate leaking propane. After searching for the culprit, it was determined that the smell was coming from decaying white radish plants.