Switchgrass is a warm-season, vigorous perennial that occurs throughout the United States. It is more abundant and more important as a forage grass in the humid portions of the central and southern Great Plains. It grows to a height of 91.5 to 152.5 cm (36 to 60 in.) and is quite leafy and has numerous short underground roots which enable the plant to increase in large dense bunches. In New Mexico, its importance in native range vegetation is limited to the eastern tier of counties, but it is not a dominant species. It may be found in rocky breaks, along shallow arroyos and places where sub-soil moisture is high.
Though palatability and forage production are both high, use of this species in range seeding programs is very limited. However, because of its vigorous root system and underground stems, it is most excellent for a conservation program. In areas of less than 50 cm (20 in.) of annual precipitation, such as in eastern New Mexico and west Texas, Switchgrass, under irrigation, furnishes excellent forage during the summer months when certain cool-season pasture grasses are producing little growth.
Commercial seed is smooth, fairly heavy, and best planted through fine seed boxes. Planting depth should be about 1.3 to 1.9 cm (½ to ¾ in.). If rainfall is ample, seeding should be done in the spring.
3.4 to 5.6 kg PLS/hectare
3 to 5 lbs. PLS/acre
NUMBER OF SEEDS:
280,000 per lb. (0.46 kg)
Alamo Switchgrass is a selection released in 1978 by the USDA Soil Conservation Service in Texas in cooperation with the Texas Agricultural Experiment Station. Alamo came from a collection originally made from a native Switchgrass stand along the Frio River in south Texas.
Alamo is blue-green in color, usually slightly waxy and taller than the Blackwell variety. The stems are slightly longer, and the leaves are usually longer and wider than Blackwell, thus extending quality forage over a longer period. Seeds are smaller than most commercial Switchgrass and should be seeded at a rate of 2.2 kg PLS/hectare (2 lbs. PLS/acre) whether broadcast or drilled.
Alamo is adapted in the south to areas receiving 63 cm (25 in.) or more of normal precipitation, or in most other areas where moisture is supplemented by irrigation or by overflow or additional runoff. Performance has been good on all types of soils from clays to fine sands, except where sever weed competition exists during establishment.
On the High Plains of west Texas and eastern New Mexico Blackwell is the most common variety of Switchgrass used in irrigated pastures and in sand hill range plantings. It was developed at the Manhattan, Kansas, Plant Materials Center and released in 1944 by the Kansas Experiment Station and the USDA Soil Conservation Service.
Blackwell ranks high in leafiness, total forage production and resistance to rust and others diseases. It is well adapted for range seedlings, pasture plantings and waterways in Kansas, Oklahoma, southern Nebraska and areas of northern Texas having 50 cm (20 in.) or more annual precipitation. Blackwell Switchgrass will grow on sandy ranges and favorable lowland sites in areas of 39 to 50 cm (15 to 20 in.) of annual precipitation.