Cannon County Soil Conservation District
Tuesday, September 13, 2011 7:57 pm

Cover crops are crops that are grown between traditional crops (corn and soybeans in this area) with the primary intent of reducing soil erosion.

 While reducing soil erosion is one of the primary objectives when planting cover crops, there are numerous benefits that cover crops can provide to the overall soil health and water quality.

Before no-till and minimum-till planting techniques cover crops were used extensively. However, with the advent of no-till planting the use of cover crops has declined considerably.

 No-till planting techniques have greatly reduced the amount of soil erosion for many years, and this practice is often viewed as the epitome of soil conservation. Unfortunately, there is one primary caveat associated with no-till farming which is that no-till requires the use (and ultimately the dependence) on herbicides and insecticides in order to control weeds and insects.

This was achieved by plowing before no-till and was the reason cover crops were used extensively. The continuous application of herbicides and insecticides has resulted in resistance to these ag chemicals over the years. Fortunately, cover crops can aid in weed suppression and attract and provide habitat for beneficial insects that will prey on the crop pest.

Cover crops curtail soil erosion by providing ground cover that reduces rain drop impact, reduces runoff, slows water velocities, and increases infiltration of water into the soil. Cover crops are an excellent way to reduce soil erosion, but they also play a major role in much more that reducing soil erosion.

Cover crops can improve the overall soil health by adding organic matter to the soil, conserving moisture, positively enhancing soil tilth (physical structure), reducing compaction, provides plant diversity, and reducing runoff of ag chemicals and nutrients into receiving waterbodies thus aiding in water quality protection and improvement.

Cover crops out compete weeds for nutrients and water and, in turn, are able to help smother out weed infestations in crop fields. Some cover crops, in particular cereal rye, actually possess allelopathic characteristics in that the plant exudes natural compounds that at as a natural herbicide. For example, positive results have been shown using cereal rye to combat mares tail (also referred to as Horseweed) that has become a problem in many crop fields.

In addition to the aforementioned benefits of using cover crops, there can also be positive economic benefits as well. When legumes are planted as a cover crop they actually add nitrogen (N) to the soil. Legumes have the unique ability to convert atmospheric N (N2) into a plant available N form through biological fixation. This added N to the soil can reduce N fertilizer needs.

Additionally, cover crops can also enhance nutrient uptake of other plants. As previously mentioned cover crops can alleviate weed and insect pressure and in turn reduce the application of these Ag chemicals.

Cover crops adapted and beneficial to cropping systems in this area with seeding rates and dates include:

Non-Legumes

Oats: 9/1   through 10/1;   1-2.0 bu./ac.

 Rye: 8/15 through 10/15; 1-2.0 bu./ac.

Wheat: 9/15 through 11/1;   1-1.5 bu./ac.

Legumes

Crimson Clover:  8/1   through 10/15; 15 lbs./ac.

Austrian Winter Pea: 8/15 through 10/1;   45-60 lbs./ac.

Hairy Vetch: 8/15 through 10/15; 20 lbs./ac.

Cost share may be available for establishing cover crops to qualifying land. For more information about cover crops please contact the Cannon County Soil Conservation District by phone at (615) 563-4321 Ext.3, or feel free to stop by the office located at 740 Old McMinnville Rd., Woodbury, TN 37920.