Summer Annual Forages following a Failed Wheat Crop
By Aaron Berger – Nebraska Extension Educator
Annual forages may play an important role in providing forage for cattle producers this year. Several factors contribute to this scenario: According to the USDA, hay stocks for the United States were the second lowest they have been for the last 25 years in December 2018, second only to December 2012. Carry-over hay this year may be limited in parts of Nebraska due to the severe winter weather conditions.
In some parts of the Panhandle, the winter wheat crop is in poor condition due to winterkill. Where this is the case, producers may want to consider either salvaging the wheat crop with grazing or for hay, and/or terminating the wheat and planting a summer annual for forage production. Visit with your crop insurance agent when evaluating the options of what to do with a wheat crop that is in poor condition.
Conditions in much of Nebraska lend themselves to the establishment and production of summer annual forages: For much of the state, the soil moisture profile is full. Additionally, the NOAA Climate Prediction Center is forecasting above-average precipitation May through July for much of the state.
Summer annual forages have varying attributes that fit different management practices. Forage yield and quality will depend on soil fertility, moisture, growing conditions and stage of maturity at harvest. Summer annual forages are the most water-use efficient and drought-tolerant of the annual forages. Forage sorghum, sudangrass, forage sorghum x sudangrass hybrids, foxtail millet, pearl millet, proso millet and teff are all options for Nebraska producers, depending on forages needs and how the crop will be harvested. The summer annual forage that is the best fit will depend upon the production system and goals of the producer.
Summer annual forages should be planted once soil temperatures reach 55 to 60 degrees Fahrenheit to ensure rapid germination. In western Nebraska, soils typically reach these temperatures in mid-May to early June. Summer annual forages can be planted through mid-July and still have acceptable yields. When grown under dryland conditions, annual forages tend to yield from 1-3 tons per acre when moisture and soil fertility are adequate.
Summer annuals can be harvested utilizing direct grazing, windrow grazing, chopping for silage or harvesting for hay. These forages can grow and mature rapidly, making it challenging to graze or harvest the crop at optimum times. The beef.unl.edu website has a number of articles, webinars and NebGuides on planting, grazing or harvesting annual forages.
Two types of toxicity are possible with summer annual forages: nitrate poisoning and prussic acid poisoning. Nitrate poisoning is most likely to occur when forage is harvested or grazed after the plant has undergone stressful growing conditions and nitrate conversion to amino acids (protein) is reduced. In western Nebraska this is most likely caused by drought, hail or frost.
Nitrate poisoning can occur in forage that is directly grazed, but is more likely to occur when forage is harvested as hay and then fed. Testing forages prior to cutting and after they have been harvested can help producers identify potential nitrate risk and manage accordingly.
Prussic acid does not occur freely in normal, healthy plants, but can occur when plant tissues are damaged due to chopping, chewing by animals or frost. Sorghum-sudan and sudan grass hybrids are the species of summer annuals that carry this risk. If planning to graze a sorghum-sudan or sudan grass hybrid, plant varieties with low prussic acid potential. Millets or teff are not a risk for prussic acid poisoning.
For more information on growing and utilizing summer annual forages, please see the NebGuides “Summer Annual Forages for Beef Cattle in Western Nebraska” and “Summer Annual Forage Grasses.”