Summer annuals are a great option for producers wanting lots of biomass production during the warmest months of the year. Species like sudangrass, sorghum-sudan hybrids, forage sorghum, teff grass and millets are all great options. With recent rains and higher temperatures on the horizon, those who need summer forage and haven’t planted yet may consider doing so soon. With several options to choose from, knowing how your plants will be harvested and ultimately used is key to success.
For those looking to graze, sudangrass and sorghum-sudan hybrids are two top options with pearl millet following close behind. While producing less overall tonnage than a sorghum-sudan hybrid, sudangrass has a greater leaf-to-stem ratio, making grazing easier with less waste. Additionally, these plants are quick to regrow, so they can be grazed multiple times over the course of the summer. Sorghum-sudan hybrids are similar in regrowth but have a bit more stem to them, resulting in more refusal and waste.
If you plan on grazing sudangrass and sorghum-type species, we need extra precautions due to the risk of prussic acid poisoning. Prussic acid or cyanide is produced in all sorghum species at various levels and needs to be managed correctly, mainly by allowing plants to reach proper heights (18 inches in most cases) before grazing. For those wanting a prussic acid-free grazing option, pearl millet may be worth looking at, as it will regrow if 8 niches of stubble is left over.
For those looking to produce hay, nearly all summer annuals are available as an option, but we do need to be aware of their strengths and drawbacks. Teff grass, for example, produces an extremely high-quality, fine hay but may lack somewhat in tones produced when compared to other options. This plant is drought hardy, however, and can produce multiple cuttings if managed correctly.
Our sorghum species are also hay options and, unlike when grazing, we don’t have to worry about prussic acid as it leaves dead plant material after a few days. The drawback with these species is often stem size. Because of this, we may want to steer away from the thickest stemmed forage sorghums. The thicker the stem, the harder it is to dry down. Be sure to use a crimper or processor when harvesting to break open the stem and dry faster. We also can increase our seeding rate at planting if we know hay is our end goal to promote a thicker stand with thinner stems.
Finally, we can consider harvesting early. Harvesting when plants have less stem and more leaf may reduce yield but will produce a higher-quality hay that is more likely to be put up at the correct moisture. Leave enough stubble height so that plants can regrow for a second cutting to make up for some of that lost yield early on.
Millet species like pearl and foxtail are great options for hay production, with thinner stems and high yield potential. Foxtail or German millet will not regrow, so cut low to maximize yield, if nitrates aren’t a concern. Pearl may produce regrowth, so depending on your timetable, a higher first cutting may be an option to consider.
Finally, silage production is an option that should be considered with summer annuals that often gets overlooked. Forage sorghum and sorghum-sudan hybrids are both high-yielding options. When compared with corn silage, sorghum shines in a few ways. First, sorghum requires less water than corn to grow, making it a great option for dryland fields. Second, from seed to inputs, production expenses are lower. Finally, sorghum can produce similar silage yields, although with slightly lower starch and energy contents than corn. Just be sure to harvest at the correct stage (usually medium to hard dough) and shoot for 60% to 70% moisture content.
Summer annual crops are a great opportunity for often much-needed forage, but with so many options, choosing the right one can be difficult. Begin with the end in mind, and selection can be much easier — sudangrass for grazing, forage sorghum for silage, teff and foxtail millet for hay. Sorghum-sudan hybrids and pearl millet are great all-around choices. With a bit of planning, your summer forage crop will be a success.
Ben Beckman is a beef systems Extension Educator serving the counties of Antelope, Cedar, Knox, Madison, and Pierce. He is based out of the Cedar County Extension office in Hartington. He may be reached by phone at 402-254-6821 or email at email@example.com.