Forage: Forage sorghum is used primarily for silage and is not recommended for grazing.
Forage sorghum originated in northeast Africa. It is a coarse stemmed warm season annual grass that can grow 15 feet tall and typically has small seed heads. The leaves are similar to corn but are shorter and sometimes wider. Seed is produced on a panicle which is open and erect. Varieties with the brown midrib gene have significantly greater digestibility and can equal the milk production of corn. There are approximately 17,000 seeds per pound.
Adaptation and Distribution
Forage sorghum is adapted throughout the United States and southern Canada. Forage sorghum performs best in moderate to well drained soils with a soil pH between 5.5 and 7.5. Drought tolerance is high with the water requirement being approximately 1/3 less than corn.
Planting rates vary from 15 to 50 pounds per acre depending on whether the seed is broadcast or planted in rows. Planting dates are usually from May to July but can be earlier in the deep South. Soil temperature needs to be a minimum of 60 degrees Fahrenheit for germination. Seeding depth should be 1 inch.
For optimum forage production, moderate fertility is suggested although forage sorghum will grow on lower fertility soils with better results than corn. Fertilize using soil test recommendations. If a soil test is not available, fertilize at similar rates to corn silage. Silage should be harvested when seed is in the milk to hard dough stage which is the proper moisture level for ensiling. Avoid possible nitrate and prussic acid poisoning by not putting on large applications of nitrogen prior to expected drought periods; do not harvest drought damaged plants within 4 days following a good rain; do not cut within 7 days of a killing frost; cut at a higher stubble height if under stress since nitrates accumulate in the lower stalk, and delay feeding silage 6 to 8 weeks after ensiling to allow prussic acid to dissipate. Never feed forage sorghum to horses.