Cover Crops And Nitrogen Scavenging

Apr 02, 2015

By Christina Curell, Michigan State University Extension

Cover crops can be used to scavenge for excess Nitrogen. The following chart rates cover crops ability to scavenge nitrogen

The reasons why farmers use cover crops are as varied as the number of species that can be used as a cover crop. Traditionally cover crops were used for erosion control but in the past few years’ cover crops have been used for other purposes.

Nitrogen is necessary for all plant growth. When added to the soil nitrogen if not taken up by the plants can move readily through the soil profile. In the worst case scenario nitrogen will leach through the soil and get into groundwater. One of the ways that farmers can reduce the chances of nitrogen leaching is to add a cover crop that will scavenge nitrogen and hold it in its plant tissue. Once these covers breakdown the nitrogen will be released and used by the subsequent crop. Remember, however, that it will take time for the plant to decompose so nitrogen will not be readily available in the spring.

The following chart rates typical cover crops grown in Michigan for its nitrogen scavenging tendencies. Do not confuse nitrogen scavenging for nitrogen fixing. These are different concepts that will be addressed and I will address them in a subsequent article.

Excellent	Very Good	Good	Fair
Cereal Rye	Annual Ryegrass	Mustards	Field Pea
Sorghum-Sudan	Barley	Crimson Clover	Hairy Vetch
Radish	Oats	Red Clover	Sweetclovers
	Wheat		White clover
	Rapeseed
	Berseem Clover

Chart information taken from Managing Cover Crops Profitably third edition, SARE Handbook Series 9.

Source: msu.edu

Video: Residue Management

Residue Management conservation practice manages the amount, orientation, and distribution of crop and other plant residue on the soil surface year-round while limiting soil-disturbing activities used to grow and harvest crops in systems where the field surface is tilled prior to planting. This video explores how Ryan McKenzie implemented this conservation practice on his farm in Samson, Alabama.

Practice benefits:

• Increases organic matter

• Improves air quality

• Decreases energy costs

• Reduces erosion

• Improves soil health

The Conservation at Work video series was created to increase producer awareness of common conservation practices and was filmed at various locations throughout the country. Because conservation plans are specific to the unique resource needs on each farm and also soil type, weather conditions, etc., these videos were designed to serve as a general guide to the benefits of soil and water conservation and landowners should contact their local USDA office for individual consultation.