Growing Cool Season Grasses with Alfalfa

Warren C. Thompson National Forage Specialist: America’s Alfalfa

Whether or not you grow grass with alfalfa depends a lot on where you live, the traditions and topography, and how the crop is to be used. If the land is inclined to erode without good cover, grass can certainly help you to nail it. If you have seeded a grazing tolerant variety and are planning to graze with beef, dairy or sheep, grass in combination with alfalfa will help protect the soils from treading damage and will reduce bloat potentials dramatically. When horses are grazed on alfalfa, grass is a sure fit mainly to moderate quality and increase fiber. 

When grass is seeded to fill the holes in thinning alfalfa stands, broadleaf weeds will be easier to control with grass in the mix. On the flip side, if the weed problem is grassy weeds, herbicides to control the likes of crabgrass etc. will also be rough on the selected grasses, especially the cool season grasses. So be aware of this conflict up front before you go full bore to the mixture.

There are some problems that you should be aware of when these two groups of plants are seeded together. 1) The protein levels will be reduced and the overall feed quality will be lowered slightly as grass is substituted for alfalfa. 2) The fertility level (especially potassium) requirement is increased. Let me explain it this way, grasses tend to overfeed on potassium and on soils that are naturally low in that element, this process happens earlier than on soils that are high in potassium resulting in early thinning of alfalfa stands. Where alfalfa and grass are grown together, most farmers solve the problem by routinely increasing potash (K20) by 60 to 90 pounds per acre at the annual topdressing to help avoid thinning and to increase annual yields.

What cool season grasses work well with alfalfa? Basically there are four species that are used in the ‘alfalfa belt’. They are listed by climatic adaptation and alfalfa compatibility. Orchardgrass, smooth bromegrass, timothy, tall fescue and Kentucky bluegrass.

Orchardgrass is widely adapted and considered the grass of choice. It is a bunch grass that tends to be less intrusive than the sod forming grasses. It is also more productive during the summer months than other cool season grasses thus providing more competition for weeds. The grazing quality is quite good and when made into hay, is very desirable for all classes of livestock especially when harvested prior to heading.

Smooth bromegrass is very high in feed quality and palatability, higher than orchardgrass. Problems, it is quite intrusive, is not as widely adapted (best suited to the upper Midwest) and does not grow as well as orchardgrass in the summertime.

Timothy is a high quality grass as well. Timothy in most areas makes little growth beyond early spring. It is the grass of choice by horse owners especially when harvested as hay with alfalfa. It is not as intrusive as the above two grasses. However, as the alfalfa stands thin, weeds usually become a problem. The best area of adaptation is in the northern Midwest and the Northeast.

Tall fescue, while widely adapted tends to be more competitive and lower in palatability than the other species. Yet in much of the Deep South, this is the only cool season grass that is well adapted that tolerates competition and resist early weed invasion. In recent years there have been some phenomenal variety improvements especially in feed quality and animal acceptability. So no longer should you count this species out when seeded primarily for grazing with our grazing tolerant alfalfas.

Kentucky Bluegrass is a sod forming-grass that when established does a fine job of retarding weed intrusion and sheet erosion. The main problems are adaptation, lower production levels and because of it’s sod-forming characteristics, often causes severe competition with alfalfa. It is a great grazing grass especially in early spring.

When should these grasses be seeded into alfalfa? Again it depends. Because of the likelihood of early grassy weed invasion in new plantings and the coming of better herbicides to control these weeds, more farmers each year are moving to seed alfalfa alone and planting grass into the fields into the alfalfa with a no-till drill a season or two later or whenever the alfalfa stands begin to thin. As for the seeding rates, check with your University or pick up a seeding chart at your County Agent’s office or from your favorite seed dealer.

Now the key question, why fool with grass in alfalfa? Grass forage is better feed than most weeds and grass does compete for space with unwanted weeds. Also, if you graze, the soil is better protected and bloat potential is reduced and often eliminated. Also when grass is included, alfalfa stands persist longer, soils are better protected from erosion, and the crop is easier to manage.