Using warm season annuals to enhance forage production

Warm-season annuals are excellent options to consider as a way to increase a farm or ranch’s forage production. As the name implies, these are a group of annual grasses that thrive the best during the warmest part of the summer. They are typically planted in June or July and can produce a forage crop in as early as 40 days. These crops can be a complement to cash grain and cover crops to enhance forage production or grazing opportunities.

The most common warm-season annual planted in the Northern Plains are the hay millets, pearl millet, sudangrass and sorghum-sudan hybrids, and forage sorghums. Each of these crops has advantages and disadvantages, depending on the environmental conditions and the planned usage.

Hay Millets

As the name implies, these crops are best suited to be harvested as hay rather than grazed or cut for silage. These are the finest stemmed and easiest to cure of any of the summer annuals. They are also the most drought tolerant and will produce forage in the shortest amount of time, about 8 weeks.

Pearl Millet

Pearl millet offers more production potential than the hay millets do. Pearl millet has the ability to re-grow, making it a better option for grazing or for multiple cuttings at any growth stage. It is not as fine stemmed as the hay millets, so it is more difficult to cure for baled hay. Unlike sudangrass, sorghum-sudangrass and forage sorghum, pearl millet doesn’t accumulate prussic acid.

Sudangrass and Sorghum-Sudangrass Hybrids

Because of the thicker stems for these crops, they are better suited for silage rather than hay. These also work as supplemental summer grazing. Prussic acid can be a concern, particularly when grazed. The greatest risk for prussic acid poisoning would occur under drought conditions, when plants are damaged by frost, or when livestock graze short regrowth.

Forage Sorghum

This crop offers the most dry matter production potential and is the latest maturing. They also tend to have elevated levels of prussic acid and shouldn’t be used for grazing. They are best suited for silage production because of stem thickness.

Other factors to keep in mind:

· As with all forages, maturity at harvest determines quality. Earlier harvest dates will result in higher quality forage, delaying harvest will tend to increase yield at the expense of nutrient density.

· Prior crop history needs to be considered as well. Prior herbicide usage, especially for products such as atrazine can impact stand establishment. Soil sampling and testing is also important to determine proper fertilizer application rates. Moreover, pest management will also be critical to obtain high yields.

· These crops can be an excellent fit for areas that were not able to be planted to row crops in a timely matter or in areas where winter wheat potential for grain is less than ideal. But before a grower considers planting an annual forage crop, they need to visit with their crop insurance advisors first to make sure they are not jeopardizing coverage and causing financial loss.

For more information, please contact Warren Rusche at the Watertown Regional Extension Center at (605) 882-5140 or contact any SDSU Extension Cow/Calf Field Specialist and Beef Extension Specialist.