Don’t want to read the whole article? Here are 8 reasons to consider cover cropping your silage ground this year.

1. Keeping ground covered year round can decrease weed pressure. If something you’ve planted is always competing against the weeds, you’ve got the leg up in the weed fight.
2. Erosion is almost inevitable on our slopes – but keeping roots in the ground helps hold the soil in place. Soil needs to stay put as much as possible, its our most valuable resource on the farm.
3. Plant material being available year round for soil microbes can do wonders for soil health.
4. Cover crops can increase drought tolerance for your crops – keeping the soil covered prevents moisture loss through evaporation and roots help water infiltrate soil. When water is being absorbed, run off and erosion are also being prevented. This is especially true in no-till systems.
5. Is mud a consistent problem for you in the winter? Cover crops can help by drawing excess moisture out of the ground.
6. What do you do when you’re cold? Grab a blanket? Cover crops can act as a blanket for the ground, holding warmth during cool periods.
7. What do you do to beat the heat on a sunny day? Seek shade? Cover crops serve that purpose too during blistering summers, shielding soil and lowering it’s temperature.
8. Need to shorten your hay feeding season or add to your stored feed? You guessed it…cover crops!

(Wisconsin Extension summarizes these benefits in the face of increasing extreme weather very well.)

Cover crop, winter crop, small grain, winter annual….whatever you call it, planting an annual crop after silage harvest is nearly always worth the resources. 

Cover crops is usually a catch-all term for anything planted behind the primary crop, such as corn for silage. True ‘cover crops’ typically aren’t harvested – they are either mowed or crushed with a roller crimper. This returns the nutrients (nitrogen, phosphorus, and potassium are the big ones we think about) harvested by the plants from the soil to the ground, instead of removing them through harvesting the plants. Valuable organic matter is also added when plants are left to decompose. In a perfect world, this would be how all annual crops were managed. We do not live in a perfect world though, and it’s hard to justify not harvesting a crop when production costs continue to rise. 

Return on investment is key for any decision on the farm, and this management strategy may have the highest ROI when transitioning from traditional tillage to no-till production. During this transition, any organic matter and nutrients added back to the soil will expedite the recovery of natural soil structure and biological activity. But, the no-till argument is one to be made another time. Back to cover crops…

Most farmers cannot justify leaving a planted crop in the field during an average year, let alone when recovering from a major natural disaster. The good news is that winter annual crops can be used for forage in livestock systems — row crop farmers aren’t the only ones who can double-crop! Winter annuals can be grazed in early spring to shorten the hay feeding season and provide high quality forage for spring-calving cows in early lactation. If grazing isn’t an option, they can also make high quality baleage or silage under the right conditions.

Small grains are the most common winter annual forage crop – recommended species are usually wheat, triticale (a cereal rye x wheat hybrid), and cereal rye. Personally, my preference is wheat or triticale. Cereal rye is quicker maturing, and while that may mean a higher yield, it also means lower quality forage. Annual ryegrass is an option as well, but is sometimes avoided as resulting volunteer ryegrass can become a nuisance (UKY AGR-179).

In a study by Virginia Tech published in 2017, several small grain species and annual ryegrass were evaluated for yield and quality both while fresh (standing) and ensiled.

The following summary of this data is not based on statistics – it’s strictly based on the numeric values provided in the publication.

Each grass species was planted in one of three combinations: alone (monoculture), with crimson clover, and with hairy vetch. Annual Ryegrass yielded the highest of the grasses when grown in a monoculture at 1.08 tons dry matter/acre as compared to cereal rye (1.05 ton DM/ac), triticale (0.94 ton DM/ac), and wheat (0.93 ton DM/ac). Cereal rye is often a popular choice because of it’s yield advantages over wheat and triticale, but it is quicker maturing which makes it less digestible than its counterparts when planting and harvest dates are the same across species. This is reflected by the higher neutral detergent fiber (NDF) and acid detergent fiber (ADF) values reported for cereal rye than wheat, triticale, and ryegrass.

Mature cereal rye, taken late Spring 2020 at the Mountain Research Station in Waynesville, NC. For reference, I am 5′ even. Ryegrass can be seen in the bottom right corner of the photo for comparison.

Inclusion of hairy vetch or crimson clover increased yield and crude protein contents as compared to the monocultures. It also increased digestibility. Crimson clover combinations had higher yields than their hairy vetch counterparts. Although both legume species increased crude protein, hairy vetch increased CP more than Crimson Clover. Frankly, there is no downside to including either legume in winter annual plantings if the intention is to either graze or terminate the planting. If you plan to harvest for silage or baleage, things get a little more complicated.

Crimson clover and wheat planted at the Mountain Research Station in Waynesville, NC. Spring 2020

When it comes to fermented forages like baleage and silage, getting the “recipe” right can make or break the quality. Forage harvested too mature or too dry? Fermentation is restricted, silage less stable when exposed to air once the silo’s opened. Forage too wet? You risk spoilage or dangerous bacterial growth. Legumes like crimson clover and hairy vetch don’t ferment well because of their high buffering capacity – basically, this means that legumes can resist changes in pH really well. Those familiar with silage production know that low pH (a higher acidity environment) is crucial to successful fermentation. Of the combinations tested in this study, those with hairy vetch had the highest pH. As such, authors recommend using an inoculant if ensiling hairy vetch. For both hairy vetch and crimson clover, be mindful of these characteristics when harvesting. Also keep in mind that there is magic way to produce high quality feed or make low quality feed higher quality. Although yield may increase, digestibility and crude protein decrease rapidly at any stage past the boot stage, and ensiling won’t change that.

The bottom line? Take care of your soil and it will take care of you. Keeping it covered with an annual crop this winter is one of the best ways to do that.