Cover Crops

County Agent News

Dan Folske

June 20th, 2011

Cover Crops

With the continuation of wet conditions throughout North Dakota, many acres will not be planted with previously planned crops. As the planting window for most crops is closing, there is a real potential that many acres will need to be planted with an alternative cover crop.

If you intend to hay or graze a cover crop before November 1st, do not plant the cover crop during the “late planting” period, which is the 25 days after the “final planting date” for most main crops, (canola and dry field peas have a 15 day late planting period), or you will lose the prevented planting payment. If you plant a cover crop after the “late planting” period, the cover crop can be hayed or grazed before November 1st, but the payment will be reduced 65%.  Under most scenarios, cover crops can be hayed or grazed on prevented planting acres starting on November 1st without a reduction in the prevented planting payment. Always talk with your insurance agent about the plans to use a cover crop especially if it will be used for grazing or haying, to make sure there is no violation of the rules.

Cover crops use some of the excess moisture in the soil, cover the soil to protect it from soil erosion, use some of the available nitrogen, promote biological life in the soil, add organic matter, and if legumes are used the plants can fix nitrogen.

Cover crops on the landscape can be mechanically or chemically terminated in the fall or if they are made up of annual species they will be terminated by a killing frost.

There are many options for cover crops on the farm. The first option is to use a species in the grass family (oats, barley, wheat, sorghum, etc). The second option is to use a broadleaf crop (field pea, clovers, turnip, other brassica species, and others) and the third option is to use a crop mixture using different species. The grasses are relatively inexpensive, can be broadcast or drilled, take up nitrogen from the soil, promote mycorrhiza growth in the soil, and broadleaf herbicides can be used if necessary to control some weeds.  The advantage of using a legume is that it can biologically fix Nitrogen. The legume biomass has about 4% Nitrogen. Not all of this Nitrogen is biologically fixed as some is taken up from the soil. For the best results field pea and other species with large seeds need to be planted with a drill or planter and not broadcasted. Other small seeded legumes and other crop species can be broadcasted and harrowed in. However using a seeder will give better results. A cocktail of different species is popular in certain areas of the state.

The benefit of cocktails is that they contain many different species and depending on the growing conditions the most adapted species will dominate in the mixture.  Warm and cool season crops can be mixed as well as broadleaf and grass species. There is not one mixture that fits all conditions. Many different mixtures can work. It will depend on the main objective of the producer. If fixing nitrogen is important the mixture should be a mix of legumes with a small percentage of other crops. If for instance late fall grazing is an objective, possibly turnips and radishes could be a component of the mixture. The more diverse the mixture the more likely it is that some of the component species will do well during the season. The cost of course needs to be considered. Weed control before seeding of a cocktail is important. A great resource for North Dakota is the “Cover Crop Chart” produced by the Northern Great Plains Research Laboratory ARS staff at Mandan, and can be found at:

www.ars.usda.gov/SP2UserFiles/Place/54450000/PDF/CCCv1-2.pdf.

Managing Cover Crops Profitably is a book with detailed information on cover crops it can be down loaded for free from the SARE website at:

www.sare.org/Learning-Center/Books/Managing-Cover-Crops-Profitably-3rd-Edition.

Another option for PP acres will be planting winter wheat this fall. The NDSU Extension Service and Ducks Unlimited have winter wheat test plots northwest of Powers Lake along Hwy 50. Plan now to attend the plot tour on July 18^th.