Grazing Bites

January 2012
Victor Shelton, NRCS Grazing Specialist

Frost seeding is certainly one of the least expensive ways to enhance the stand of legumes in your pastures.  It is basically the process of broadcasting the legume seed onto the soil surface during the winter dormant months.  For the most part, I usually say the ideal time period is somewhere between Christmas and Valentine’s Day.  If I really had my choosing, I’d wait until there is a light snow on the ground and then do the sowing.  The snow serves two good purposes.  One, is helps “catch” the seed and transport it to the ground and two, it serves as a great marker for the tractor or ATV. 

Occasionally in the Southern portion of the state we are a little more limited with the most ideal conditions to really “frost” seed.  Frost seeding relies on the freezing-thawing action of the soil, which is honeycombing of the soil surface with ice crystals.  This causes the soil surface to expand and contract thus allowing the small seed to find a route into the ground.  During warmer winters, you might not always get enough action and if you don’t get good seed to soil contact and the seed does not get covered; then it is less likely to survive.  I doubt that will be the problem this year.  Too often, when left laying on the soil surface, the sun can warm the ground and seed enough to initiate germination…and it has little chance of surviving if this happens before the occurrence of another killing freeze.  The seed that is protected by the soil will not be as likely to be impacted by the sun and is more likely to wait until the proper time period to germinate.

Competition is probably your next worst enemy.  Now, I would hope that most would not consider broadcast seeding or frost seeding into a heavy stand of grass… but I have seen it done and usually with less success.  If you know you are going to be frost seeding legumes into a pasture then I would recommend, after the forage has become dormant, to graze it down to about 3-4 inches to remove any excess growth (not particularly a problem this year was it) to allow the seed to find its way to the soil surface and wait for that freezing action.  Grazing closer to the soil surface also helps to depress early spring growth of the grass which will give the legume seedling a fighting chance.  Now that reminds me to mention before I forget, don’t hit those newly seeded fields with nitrogen in the spring either.  All this does is to promote the grass growth in the sward, and reduce those new legume seedlings chance.  They won’t have the root base or energy stored up to compete with established grass, especially with a boost of nitrogen!

It is certainly not out of line to continue grazing stockpiled forages such as tall fescue even after you have frost seeded the legume on.  The hoof action caused by the grazing livestock can actually help increase that good seed to soil contact we are looking for unless we get into soft wet conditions which would not be ideal for the pasture or the seed.  We want to plant it not bury it.  As long as conditions are favorable, the grazing will continue to provide positive action, weakening the grass stand, and open up the sward.  All this will slow down that early spring growth allowing the seedlings a better chance.

Of course, an alternative to frost seeding the legume is to wait until favorable soil conditions later in the spring and drill the seed.  This still requires the same “ideal” conditions discussed above.

I suppose we should discuss seeding rates.  I usually recommend slightly higher seeding rates for frost seeding than for conventional seeding.  White clovers can be seeded at 1-1.5 lb per acre, remembering that it is a lot smaller seed than red clover and will be around longer.  You can get it on too thick and yes, I know, it’s hard to seed that small amount!  You can also mix the seed in with fertilizer (no nitrogen…and watch the amount of DAP) or some pelletized lime.  Red clover should be seeded at 6-8 lbs per acre; birdsfoot trefoil at 5 lbs per acre and common lespedeza with hulled seed at 10 lbs.  All legumes should be inoculated with the appropriate inoculants for that species to insure proper bacteria, good germination, and growth.  Coated seed, when available can solve lots of problems including seed size, the inoculants, and can even help the pH for the seedling.  I do not recommend it, but alfalfa can also be frost seeded, but is more pH sensitive and certainly does better being drilled.  If frost seeded, then use at least 8-10 lbs per acre. 

As spring starts pushing new growth in our newly amended pastures; remove early grass growth by grazing to allow for sunlight to get to the newly germinated legume seedlings.  Keep growth under control by grazing or haying until the newly planted legumes have established themselves.

About 15 years ago I frost seeded several replicated plots of different legumes and grasses.  Though I have seen on occasion, that almost anything works, the clovers, lespedezas, and then lastly the trefoil did the best.  Seed to soil contact and competition was especially critical to the trefoil.  Only redtop, timothy, Switchgrass and ryegrass, as far as grasses were concerned, faired out.  Larger seeded grasses and alfalfa certainly did better when drilled instead.  I continue to test new potential forages for this purpose…and we have some real promising ones which I’ll tell you about later if they pan out.

In conclusion, the main points for a successful frost seeding of legumes is probably grazing the pasture down before seeding to lower the amount of dry matter, seed during freezing and thawing conditions to help move the seed down into the soil, and then keep grass growth under control during early spring to give the seedlings plenty of sun and a fighting chance to survive. 

Getting more diversity into the pasture is always a good thing.  More diversity, more choices for the livestock and more opportunities to provide needed nutritional needs for the adjacent plants, the livestock, the soil micro organisms, and then back through the same system again.

More diversity and more plants per square foot also help to make sure that the soil is covered at all times.  I would rather see or have too much vegetation than not enough.  Keeping the ground covered helps to build organic matter, increase infiltration, decrease drought problems, and again, feed the organisms that help to feed the forages, and thus the livestock.

As always, keep on grazing!

2012 AFGC Annual Conference, January 9-11 in Louisville, KY - For more information www.afgc.org

Winter Forage Seminar, January 10, Gasthof Amish Village, Montgomery, IN – 9:30 to 3:00 ET, Contact Abe Raber for more information at 812-636-2272.

Indiana Forage Council Annual Meeting, January 31, 2012, Gasthof Amish Village, Montgomery, IN – Presentation by Gary Zimmer of Midwestern Bio-Ag – for more information contact Keith Johnson at 765-494-4800.

Heart of America Grazing Conference (HOAGC), January 25-26^th, 2012, Mt. Vernon, IL – For more information contact Teresa Steckler, Dixon Springs Ag Center, (618) 695-4917 or tsteckle@illinois.edu or go to http://web.extension.illinois.edu/ajmpu/hoa/

Southern Indiana Grazing Conference (SIGC), February 1, 2012, Simon J. Graber community building, Odon, IN – Speakers Greg Judy, Ray Archeleta, Gary Zimmer and Dave Robison – Contact Toni Allison at (812)254-4780 Ext 3 or go to http://daviesscoswcd.org/main/page_sigc.html 

Northern Indiana Grazing Conference (NIGC), February 3-4, 2012 – Speakers include Kerry Estes, Dave Heidel, Keith Johnson, Jerry Perkins & Family, Greg Gunthorp, Jack Lazar and more.  More details coming.  Contact Dona Hunter for more information at 260-463-3166.