Texas

In areas where spring hail storms have damaged early planted crops beyond profitable production, growers may be able to utilize warm-season, annual grasses to their advantage in late-planting situations. With the climatic instability of the High Plains and chances of severe weather, it is a good idea for farmers to have a backup plan in the event their primary crop is destroyed. Some regions of West Texas have experienced cotton crop losses due to hail and high winds in recent weeks and are facing tough replant and insurance decisions.

Sorghum and pearl millet forages allow for large amounts of forage to be grown in a short amount of time, combined with a great diversity of management and harvesting options. Sorghums and millets can be stored as chopped silage, wrapped bale silage, grazed, green chopped, or cut for hay. In addition to the advantage of a later planting date, sorghums have the ability to maintain high yields under water stress conditions and resume growth after drought. They work well in limited irrigation or dryland situations and are useful in either conventional or no-till operations. Sudangrass and sorghum-sudangrass hybrids are used extensively as pasture and for greenchop or hay production. These grasses grow 4 to 8 feet tall, have smaller stems and are more leafy than the forage sorghums typically grown for silage and are therefore, managed differently. Planting should be after soil temperatures reach 65°F, especially in the case of millets, and can be achieved with planters, drills, or broadcast at rates that vary depending on method, row spacing, irrigation, and harvest goals. Seed the grasses at higher rates when being utilized for grazing or haying and at lower rates if grown for greenchop or silage. Sudangrass, sorghum-sudangrass hybrids and millets can be cut multiple times during the growing season to provide continuous, highly nutritious feed. For optimization of forage quality and yield, plants should be cut at boot stage prior to head emergence. First cuttings are possible 60 days after planting and then every 30 to 35 days thereafter. Growers should keep in mind that the grasses need to be at least 24 inches tall prior to cutting and a stubble of about 6 inches should be left. High cutting promotes vigorous, leafier regrowth. Pearl millet is particularly intolerant to low cutting. Varieties with large stems may require conditioning if being dried for hay. Three to five tons per acre of dry forage are possible with each cutting under irrigated conditions. However, under dryland conditions, yields are closer to two tons/acre in dry years.

Although the grasses respond to increased fertility, they perform well on questionable, low-fertility soils, which makes them useful on less productive land. Fertilizer needs will vary depending on irrigation and expected yields, but generally, 60-100 pounds of nitrogen per acre are required at planting and 40-60 pounds of nitrogen are recommended after every cutting or every 4-6 weeks of grazing. Another benefit of these forages is that they are an excellent smother crop and will suppress weeds because of their competitiveness and shading characteristics when seeded at high rates. Growers should be aware of restrictions on herbicides used for the previous, damaged crop (especially cotton) and if they will prevent the planting of sorghum (forage types) or millets. The same herbicide precautions must be taken when returning back to the primary crop the following year.

Grazing is the cheapest method of harvesting warm-season annual grasses, but often times requires the highest level of management in order to match animal nutritional needs with plant quality. Because of their greater proportion of leaves, smaller stems, and extensive tillering, sudangrasses are preferred for grazing purposes. Keep in mind that heavy trampling losses can occur and steps should be taken to rotationally stock so that plants can recover from grazing pressures. Staggered planting of separate paddocks will help in this regard and will help maintain grazing at optimal vegetative stages. Plants maintained in a vegetative state have the highest quality and nutritive value begins to decline significantly after heading.

It should be noted that sorghum and millet grasses have the potential to be very toxic to animals consuming them, especially the sorghums. Two concerns that producers should be aware of are nitrate toxicity and prussic acid poisoning. Prussic acid, or hydrocyanic acid, in the plant is readily absorbed in the bloodstream, leading to respiratory problems and eventual death if high enough concentrations are consumed. Nitrates, when converted to nitrites, interfere with the ability of red blood cells to carry oxygen, and animal death can result. As a general rule, anything that suppresses or disrupts growth of leaves relative to roots (i.e. drought, overcast days, frost, low temperatures, shading, herbicide damage, hail, disease) could contribute to increased levels of nitrates and prussic acid in the plant. Excessive nitrogen fertilization may result in toxic forage as well. Caution is warranted when nitrate levels exceed 2,500 ppm or prussic acid exceeds 600 ppm on a dry matter basis. Young plants are more toxic than mature growth and plants must be at least 18 inches tall before turning animals out on pasture. Waiting four days to one week after a stressful environmental condition before allowing animals to graze is recommended and forages should be tested before any type of grazing or feeding. Haying toxic forage will not reduce nitrate levels, but prussic acid will deteriorate after one to two weeks. Ensiling will reduce both by about 50 percent. Prussic acid poisoning is not a concern in pearl millet production; however, nitrate toxicity is. Horses should not consume sudangrass or sorghum-sudangrass hybrids in any form.

Despite these concerns, warm-season annual grasses may be particularly useful in regions with high concentrations of beef and dairy cattle, such as the Texas Panhandle and eastern New Mexico. Although energy of sorghum and millet is lower than that of corn, protein levels are similar or higher and yields may be just as high if managed properly. They are highly digestible in a vegetative state and are readily consumed by livestock. Introduction of brown mid-rib (BMR) varieties has improved digestibility of forage type sorghums, but standability issues have limited broad acceptance of the BMR's. However, newer varieties have shown evidence of reduced lodging.

If there is a demand for such hay or greenchop products, planting these rapidly maturing grasses might be a good decision. As with any crop, proper management and timely harvesting are crucial for good returns and profitability. Seed companies may have contracts for seed production of the forages and Farm Service Agency has indicated a Noninsured Assistance Program full coverage insurance date of July 15 for some of these crops. Always check with your local FSA office concerning government programs you are participating in for appropriate alternative crops that will not negatively affect compliance and for crop eligibility. For more information on sorghum and millet forage production in the Southern High Plains, contact Mark Marsalis, Extension Agronomist, New Mexico State University, Agricultural Science Center at Clovis, 505-985-2292, marsalis@nmsu.edu.

Date: 6/21/05

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