SELECTING A HYBRID
It is important to begin thinking about hybrid choices during the early winter months and to book your seed early. To assist in your decision for the hybrid that best fits your operation, university and company data is available. Planting more than one hybrid should be considered to help spread risk.
When selecting a hybrid, there are many things to consider. The length of hybrid maturity is key because the longer the maturity typically the higher the yield potential. Factors to evaluate in terms of hybrid maturity include the length of the growing season in relationship to desired planting date as well as yield potential based on soil quality, water availability, both irrigation and rainfall. If a given environment will not support high yield potential, then a shorter maturing hybrid is more appropriate.
Other factors to assess include the adaptability of the hybrid to the region and the yield potential of the hybrid given its maturity and its standability. A hybrid’s head exertion is also important as it will help with harvestability. Evaluating a hybrid’s drought tolerance is essential if it will be grown under dryland or limited irrigation. Insect and disease resistance are also key aspects to consider. When considering which hybrids to plant, when at all possible, examine data over multiple years.
Sorghum Sudangrass Hybrids
Sorghum sudangrass is a cross between sorghum and sudangrass, and is characterized by relatively small-diameter stems, high tillering capacity, rapid regrowth potential and low grain yield. Sorghum-sudangrass hybrids can produce good quality silage but are best suited for grazing or hay production. Heads of sorghum-sudangrass have an open panicle very similar in appearance to Johnson grass.
Forage Sorghum Hybrids
In general, forage sorghum hybrids are similar to grain sorghum but are taller, leafier and may produce less grain. Forage sorghums can range anywhere from 6-14 feet in height. Stalks are usually large in diameter and some may contain a sweet juice. Seed heads may have a more open panicle with smaller seeds than grain sorghum. Milking and feeding trials have shown that forage sorghum silage can be equal to corn in milk production and cattle gain. One distinct advantage of forage sorghum over corn is that it requires significantly less water. When choosing a variety for silage production, both yield and quality should be considered.
Conventional Forage Sorghums
Typically, silage sorghums are 6-10 feet in height. Quality can be variable, but there are some conventional varieties with excellent quality. When short enough for combining, it can be considered dual-purpose in that it can be harvested for either grain or forage. In general, as the grain yield is increased in conventional forage sorghums, so is the digestibility or energy value of the silage.
Brachytic Dwarf Forage Sorghum
These forage sorghum types are generally shorter than conventional varieties, typically less than 6 feet tall. They are characterized by short internodes giving the plant a leafy, lush green appearance. These varieties are new and little testing has been completed in university trials. However, it is expected that overall quality will be improved as a result of the higher leaf to stem ratio compared to conventional forage sorghum. Varieties are available that combine the brachytic dwarf and BMR traits.
BMR Silage Sorghum
BMR silage sorghums have a brown midrib trait on their leaves. Some varieties will also exhibit a brown stalk pith. These varieties have less lignin content than conventional sorghums. Lignin is the primary indigestible component of many forages and significantly reduces digestibility within animals consuming the plant material, including leaves and stalks. Lowering the lignin content increases the overall digestibility of the fiber component of the forage, thus improving overall quality. As a result, some sorghum varieties now have energy values equal to that of corn, and acceptance among feeding industries that require high energy like dairies is growing. Research suggests that the BMR trait can lead to reduced dry matter yield and increased lodging. However, these problems are variety specific and certain cultivars perform better than others. The main issue associated with less lignin content is increased lodging potential. This potential problem, however, can be compensated for with appropriate management practices. While some general inferences of the BMR source can be made in relation to yield, quality and agronomic characteristics, the overriding consideration in choosing a variety should be based on the traits of that particular variety rather than the source of the BMR trait.
Forage Sorghum Management, Hybrids Determine Silage Value
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