Interest in cover cropping is growing by leaps but I consistently see people make four big mistakes when grazing those crops.
1. Not enough species. Adding a single species to wheat or rye might sound helpful, but those with experience say you should add multiple species; within reason, the more the better. The idea is to mimic nature's model, which uses multiple species to increase opportunities for soil biology to grow. It is the creatures which live in the soil that actually improve it. In fact, they make up much of any measured organic matter increases you may attain.
I wrote about number of species needed in a blog in March 2013 addressing the work of farmers Dave Brandt in Ohio and Gabe Brown in North Dakota. One thing particularly interesting is that Brandt's on-farm research showed that more plants and nine species actually increased yields and used no more from the soil water profile versus simpler mixes. The Browns have similar experiences and sometimes include more than 20 species in mixes.
A cool online tool to acquaint yourself with cover crop plants and the purposes eat one serves is Green Cover Seed's Smartmix Calculator.
2. Too short. It's especially common in the Southern Plains, where I live, and I think generally in lower-rainfall areas, for producers to plant a cover crop and then dump cattle on it as soon as they see some green. This defeats many of the reasons for growing a cover crop, but foremost it prevents the plants from growing full and deep root systems to feed the soil life and build organic matter.
If fall grazing is hole in your program, then plan to hold over some warm-season cover crops for grazing while you wait on cool-season crops to develop good roots and ample grazing. A mix of warm-season crops with a few cool-season plants blended in can increase the quality.
3. Continuous grazing. I continue seeing cattle running loose on cover crops for the entire grazing season and/or for long periods at very low stocking rates. This is very poor use of resources and destroys soil health rather than builds it. When left out for long periods cattle can graze selectively and eat all their favorite or most-familiar plants first. Sometimes this leaves lower-nutrition plants behind. Sometimes you'll leave plants like buckwheat behind, which can create some light sensitivities issues when grazed alone. In either case you may expect the cattle to eat these and other plants of low quality late in the grazing period. Then you'll likely complain about performance.
Further, the constant walking and trailing over long periods actually compacts the soil much more than short-duration, high-stock-density grazing. It also does a poor job spreading manure and urine when compared with HSD grazing.
4. Taking too much. Fear of waste is a negative emotion and it's extremely counterproductive when grazing cover crops -- and perennial grasses too, for that matter. Your goal should be to eat no more than the best third of the crop and mash the rest down on the ground. This puts the best nutrition in the cattle and covers the ground with vegetation. This protects the soil life from heat and from cold and it feeds the soil life at the same time.
Incidentally, it can be well argued that not grazing cover crops is a mistake as well. Cattle and other livestock can be a wonderful way to turn some of that slow-decomposing vegetation into pre-digested food for soil bacteria. That speeds up the process of soil regeneration, especially in more brittle environments.
There are cover cropping workshops upcoming this winter where you can learn how actual producers are managing cover crops to build soil and make money from those crops with cattle.
One workshop I'm attending in January is the Southern Soil Health Conference, January 16-17, at Fort Worth, Texas.
The No-Till on the Plains Winter Conference is Jan. 27-29 in Salina, Kansas, and always focuses some of its workshops on cover cropping.
Another soil health workshop called Farming Evolution 2015 is in Holyoke, Colorado, Feb. 12-13.
The Midwest Soil Health Summit is in Alexandria, Minnesota, Feb. 18-19.
If you know of more soil health workshops, please post them in the responses below this blog.
Also, watch for our special soil health issue in June 2015 Beef Producer.