Summer annual forages help maintain productivity as cool-season, perennial grasses enter their summer slump. They can be utilized for summer grazing options or to grow additional feed during the summer, reducing your need for stored feed or the expense of importing it. They are good choice for filling this gap in productivity because they yield well in a short time, growing fast enough to outcompete many summer annual weeds and due to a short (30-35 day)cutting cycle, harvesting them helps control perennial weeds as well. The summer annuals are also useful in interrupting pest lifecycles, and are also good insurance in times of drought, since many are well-adapted to hot, dry climates. Sorghums and sorghum-sudans, as well as grasses like teff and millet, can thrive with less moisture than corn.
It’s important to anticipate both the soil temperature requirements for correct planting dates and the harvest schedule and plan for them in your rotation. Summer annuals can be planted separately or used to replace perennial pastures within the same field. This is sometimes known as break cropping – the process of breaking up your rotation by mixing annuals into perennial fields. The “renovation-rotational” effect helps eradicate perennial weeds, and the annual will often smother what’s left.
Calculate and compare your expected yield from the summer annual with the yield you would get from the perennial pasture to make sure it is the appropriate substitution.
BMR Sudan x Sudan hybrids carry the BMR (brown mid-rib) trait that makes the non-grain portion of the crop highly palatable and digestible. It has strong tillering and excellent regrowth after grazings and cuttings. AS 9301, our popular BMR-6 hybrid sudangrass, has the gene 6 high quality added to its characteristic fine dry stalk (aiding quick drydown), fast regrowth, and exceptional drought tolerance. Seed it with a drill after soils have warmed to 60 degrees, and cut with sharp blades when the crop is 36 to 40 inches tall. Mechanical cutters should be set to leave 2 nodes or 4 to 5 inches of stubble, which encourages quicker regrowth. Sharp cutting blades avoid tearing and susceptibility of diseases in torn stems. Cattle can typically begin to graze when the crop is 24 inches tall.
Prussic acid is a concern in sorghums and sorghum-sudans in the fall; delay grazing for seven days after a hard frost, and avoid grazing when plants are very short or in a new growth stage. Avoid grazing wilted plants or plants with young tillers, and allow silage to ferment at least 6 to 8 weeks before feeding. We carry many exceptional BMR sorghum x sudan (sorghum-sudan) hybrids as well, notably:
- AS 6201 – A fast starter with a shorter harvest window
- AS 6401 – Improved disease tolerance, regrowth, and cold tolerance
- AS 6402 – Tolerates shorter cutting and grazing heights
- AS 6501 – Photo-period sensitive for a wide harvest system (1 cut system)
BMR Tillering Corn (MasterGraze) is a highly digestible corn crop suitable for a one-cut or graze system. The MasterGraze should be planted with a corn planter, in 15 inch rows. You can double back with the planter to get this configuration. Target a seeding rate of 36,000 to 44,000 plants per acre, split the per acre seeding rate in half and plant in 15 inch rows doubling back. Have mutilple planting dates to enable subsequent grazings. Harvested at tassel stage, MasterGraze has a high sugar content and is ideal for dairy or finishing livestock. It is ready for harvest in 60 days and its tillering habit helps boost its yield (5-7 tons of dry matter per acre). Growing corn that can be grazed saves money in harvesting and storage costs, and allows the animal to benefit from the higher quality that is lost after harvest.
When grazing MasterGraze, start before tillering and plan to graze through the tillering stage for optimum quality. You will need to walk or drive down the crop to run your polywire to set up grazing sections. Cattle will graze up to the wire, typically grazing the leaves of the plants first and then the stalks.
Millet is similar to sorghum-sudan – a drought-tolerant grass, fast-growing and yielding well in dry times. The quality can be as high as sorghum-sudan, but its yields average about 20 percent lower. Millet grows best in a temperature range of 77 to 86 degrees F. Once soil temperatures are warm enough for quick emergence, herbicides are rarely needed for weed control in millet. Millet is good for grazing, green chop, dry hay, and silage. Millet will do somewhat better than the Sorghum-sudan on wet soils. Millet can be fed to horses and mules, in addition to livestock.
Brassica crops, such as turnips or radishes,are often planted as cool season annuals, but are productive forages in the summer, high in protein ranging from 16 to 32% and lack the lignification potential of many grasses. They can be seeded alone or with annual grasses for more fiber and better digestability. Either way, make sure to introduce livestock to these crops gradually and supplement with adequate fiber to slow the rate of passage and allow for proper digestion.
Teff, originally from Ethiopia,is a small-seeded grass that needs very careful planting and management. Accurate seedbed preparation and planting are critical with teff. If managed correctly, it will yield an excellent hay crop and can fill the summer gap left by the cool season grasses. It can provide several grazings or cuttings throughout the season. For grazing applications, the key is to cut the first harvest, then manage graze subsequent harvests.
There are also several warm season legumes to try, including soybeans, cowpeas, lentils, lespedeza, and lablab.
Planting and Harvest
If time allows, two or more plantings of summer annuals at different dates can extend the harvest and grazing season and allow you to add more variety to the crop.
As with any planting, know your soil. Proper pH, phosphorous and potassium are crucial. 60-100 lbs/acre of nitrogen can be added at planting time if needed. Account for nitrogen credits from the applied manure and from soil organic matter nitrogen that becomes available during the summer.
In no-till systems, a successful planting requires a burn-down herbicide like Gramoxone Extra or glyphosate (Roundup). Plant on well-drained, level soils. Alternatively, interplant rows of summer annuals into a sparse pasture with a sod-seeder. Check seeding depth: Sorghum-Sudan hybrids 1” to 2” Sudangrass hybrids ¾” to 1.5”; millet ½” to ¾”, brassicas 1/8” to 3/8” teff 0 to 1/4” max.
For sorghum -sudans and sudangrasses, when planting in very dry soils that may be hard, additional weight may be needed to be added to the drill, in some cases up to 1000 lbs of suitcase weights if the soil is very hard and dried out.
For conventional planting, prepare the seedbed carefully. Break up large clumps, remove plant residue, and cultipack.
Weed control is often not much of a problem, since summer annuals grow so quickly. Plant ahead of or after typical timing of weed flushes.
The crop should generally be harvested at 18 inches tall and before seedheads appear; allow 4 to 6 weeks of regrowth before the next cutting.
If you are using the crop for silage, cut at boot stage and get it to around 65% moisture (70% for sorghum-sudans). Shred the material finely and pack it tightly. AS9301 Sudangrass can be made for dry hay.