Home Pasture Health Forage Summer Annuals, the Nutritious Pasture Refresh Button

Summer Annuals, the Nutritious Pasture Refresh Button

Grazing sorghum-sudan and brassicas

Q: We are located in central Missouri and have a small cow calf operation (38 cows). Our pastures are mostly fescue with some other grasses and clovers mixed with the fescue. We have been planting annual rye in some of our pastures that are not heavy fescue sod. We have been thinking of purchasing a roller crimper and planting a summer annual in mid May and planting annual rye in late August. What summer annual would be good for this? Would a mix of radishes and turnips or any other mixes be good? Would it be better to plant them in the summer annuals or winter annuals? Or use a summer and winter annual mix?

Getting rid of toxic fescue can be a process but it is vital to your success.

Not in the market for replacing your tall fescue? Jim Gerrish has suggestions for managing your grazing so you can use it effectively. Click to read more.

If this fescue is a toxic endophyte type, it really needs to be taken out and reseeded. The endophyte in K-31 is harmful to animal health and performance, and getting good lasting dilution from other species is not often successful. Trying to kill perennials in general with rolling alone won’t work since they will just regrow (unlike rye, which is rolled toward the end of its lifecycle); and trying to interseed into the fescue won’t work in a lasting way, since the animals will select for the fescue by picking out the more palatable interseeded species.

Taking out the fescue by spraying and rotating into summer and winter annuals is the best option to renovate the field and suppress the fescue.

Not only do you get the rotational benefits of a break crop to rejuvenate the pasture, but incorporating annuals is also an excellent way to add variety to your rotation and solidify forage inventories. The short growth season of many summer annuals gives you the flexibility to double crop with another annual or fit in a timely pasture reseeding, which is helpful for maximizing overall rotation productivity.

Summer annuals are more work but it’s worth it.

Grazing sorghum-sudan and brassicas
Grazing sorghum-sudan and brassicas

Planting summer annuals is an extra cost for your system, but if managed correctly, the high yields and quality of quick-growing summer annuals and the average daily gains they produce make it well worth it. Their summer growth will of course be far from what you’re used to from perennial stands and will take some adjusting in your grazing program. Summer annuals can grow several inches a day with good moisture and fertility conditions, so it’s best to start grazing them on the early side, using a higher stocking rate than you would with perennial pastures.

For rapid gains during the summer months, feeding a high quality, highly digestible forage is key. With good planning and use of these forages, average daily gains can reach 1.4-2 lbs/day (according to the University of Georgia). Brassicas such as radishes, turnips, or hybrid brassicas are one of the highest quality forages you can feed, and these can be planted in mixed stands or straight stands of only one species of brassica. They go well in the context of either a summer annual forage mix or a cool season fall mix (many do not over-winter well). Brassicas are high-moisture and high protein crops, however, and a companion grass is usually needed to slow down the rate of passage when feeding (or supplement with dry hay). Plant them together with a sudangrass or millet. Both sudangrass and millet are fine-stemmed, with a high leaf to stem ratio, and are good regrowers.

Many sudangrasses and some millets are also BMR products, which means they are bred for reduced lignin and higher digestibility. Dwarf products on the market are also useful, since this increases the amount of leaf material in relation to the stem. Sudangrasses and sorghum-sudans also make excellent smother crops for renovating a fescue stand. Millet is slightly more tolerant of drought and lower pH, but the yield will not be quite as high as sorghum-sudans.

Crabgrass makes a nice reseeding summer annual, and is compatible in a fescue stand. A nitrogen application in early summer helps stimulate the crabgrass stand, which starts being quite productive just as fescue production drops off.

Teff is also an excellent forage, but it’s best grown for hay. With its shallow root system and fine stems, it is easily damaged by grazing traffic.

There are many options for multi-species summer grazing.

Cows Grazing Brassicas
Cows Grazing Brassicas

For a nice mixed forage, a combination of tillering BMR corn and cowpeas is a high yielder, and high in protein and digestible fiber. The corn forms a dense stand in 15 inch rows, while cowpeas (often drilled across the rows of corn) fill in the spaces to provide weed control and climb the corn plants. When grazed after 60 days of growth (prior to corn tasseling), the result is a combination high in effective fiber and protein. This crop can be a challenge to manage with machine harvest, but the high volume of moist material (about 4 tons of dry matter) is perfect for a one-time grazing.

An alternative is a more diverse mix for summer grazing, also intended for soil-building. Ray’s Crazy Mix is a seven species summer annual product that includes sorghum sudans, radish, hybrid brassica, cowpeas, and sunflowers.

In addition to the nutritional qualities of this mix, it’s quite effective for competition against weeds. The large brassica leaves and other broadleaves in particular shade out summer annual weeds that are also fast growers.

After the summer annual, you can easily transition into a winter annual like rye, or use a small grain and ryegrass-based mix. A very productive one that we have found is triticale and annual ryegrass, or a more complex mix of winter annuals. At King’s AgriSeeds we have a newer mix called Soil Builder Plus, which incorporates triticale, crimson clover, hairy vetch, annual ryegrass and Daikon radish. It builds soil, fixes nitrogen, and suppresses weeds over winter, while providing a high-yielding grazing mix for spring.

The roller has select applications only.

When it comes to using a roller to transition between crops, this is not recommended on a perennial stand. A crimper-roller is an excellent tool for the right crop, but if it is to be the sole method of kill (i.e. in the absence of herbicides), a great majority of the crop has to be at heading or bloom stage. With mechanical interventions like cutting or rolling, perennials simply regrow. They require herbicide application or full tillage to really terminate the stand along with many of the accompanying weeds.

Rollers also are not recommended on complex mixes, since the many species in the mix increase the likelihood that the whole stand is not heading out or blooming at the same time.

So in transitioning between perennials and annuals in the process of a pasture renovation, full tillage or burndown herbicide really is the most effective means of getting the new crop established and the weeds under control – especially in an organic setting.

On Pasture Readers – Do you have suggestions?

We’d love to read your thoughts and ideas in the comments below!


  1. Dr. Michael Peel of ARS did a study measuring Sainfoin resistance to glyphosate. It slows down, but can recover nicely after being sprayed with up to a quart per acre. This makes is a great pasture renovation plant; plant and re-spray a time or two for a year or two until the fescue is gone; then interseed with the desirable grass of your choice.

    Sainfoin can’t handle grazing in a mix because it is too palatable, so use short duration grazing or cut it for hay.

Comments are closed.