– Glen Arnold, OSU Extension Manure Management Field Specialist (This article first appeared in the September 2, 2016 on-line issue of Ohio’s Country Journal)
Livestock producers will soon be applying manure following corn silage harvest. Both soybean and corn harvest will be about normal this year. To best capture the nutrients in manure, livestock producers should incorporate fall applied manure and also consider using cover crops.
Fall cover crops have been planted in Ohio for many years. While primarily used to help control soil erosion, cover crops can also recapture nutrients in livestock manure and keep these nutrients from escaping into lakes, streams and rivers.
The most common cover crops used with livestock manure are cereal ryegrass, oats and radishes. However, farmers have also used wheat, clover, annual ryegrass, or almost anything they are comfortable growing.
- Cereal ryegrass is the best cool-season grass for capturing excess nitrogen. Because rye over-winters, research has shown it can capture and hold 25 to 50 pounds of nitrogen (organic form). It germinates at lower temperatures than oats so may be planted later, but less nitrogen will be recycled the later the rye is seeded. It will grow later in the fall and begin growth earlier in the spring than wheat.
- Oats are sometimes used as a cover crop in the fall and need to be planted soon after silage harvest. Drilling oats improves germination and growth before frost. Some farmers in northwest Ohio have had great success surface seeding oats and incorporating with shallow tillage. Oats winter-kill and are not a problem in the spring for no till or minimum tillage systems.
- Another cover crop that is excellent at recycling nitrogen is oilseed radish. Oilseed radish is a fast growing, non-legume broadleaf that needs nitrogen to grow rapidly so it is often used with livestock manure. Needing time to grow, radishes are usually not the best option following soybeans or corn in October. Radishes typically winter-kill when temperatures reach 20 degrees F but farmers in Ohio occasionally report radishes surviving winters thanks to snow cover when temperatures are their coldest. Surviving radishes were easily controlled with a burndown herbicide.
Cover crops can help livestock farmers recapture manure nutrients and conserve soil by reducing erosion. Cover crop seedings do not have to be perfect. The goal is to combine nutrient recovery and to protect the environment.