Adding radish to your breakfast cereal would likely give you gas. But that's not what we're talking about here.
Research into multiple-species cover crops has "opened the bag" to many seed combinations of grasses and legumes. One particular combination drawing unusual farmer interest is drilling forage radish seeds along with wheat or barley crops.
Why? The Daikon forage radish is has a thick taproot that grows 12 to 20 inches long. Trademarked and sold as "Tillage Radish" or "Groundhog Radish", they have much longer taproots than conventional oilseed radishes, according to Ray Weil,
Seed company promotions cite a 5- to 12-bushel per acre wheat yield increase. Those reported gains are based on farmer testimonies – not replicated university trials.
"I can't confirm (the wheat yield increase) as I haven't done any trials," says Weil. "I've certainly heard testimonials, and it may be possible that enough nitrogen and maybe sulfur and phosphorus is mobilized and returned to the surface soil in time for wheat green up . . .. That would be my research hypothesis."
Kevin Conover, University of Maryland farm manager at Beltsville, Md., says a replicated wheat study is being done at Beltsville this fall. But no one at University of Maryland has done such a study in the past.
When killed by a winter freeze, they rapidly decompose, creating vertical holes to break up surface compaction and release nitrogen taken up from the soil profile in the following spring.
To achieve enough growth to capture soil nitrogen, forage radishes need to be planted at least four weeks before killing frost.
General recommendations for seeding with wheat is to drill two to three pounds of radish per acre.
Odor is one undesirable after-effect of decomposing forage radishes. The rotting plant material has been known to cause emergency phone calls by down-wind neighbors to local fire departments concerning potential gas leaks.