Forages: Annual Species

Excerpt from Agronomy Guide for Field Crops (Chapter 5)

Order OMAFRA Publication 811: Agronomy Guide for Field Crops

Table of Contents

1. Annual Forages
   • Winter Cereals (Rye, Triticale, Wheat)
   • Spring Cereals (Oats, Barley, Triticale)
   • Cereal-Pea Mixtures
   • Forage Soybeans
2. Warm-Season Annual Grasses
   • Millets
     • Pearl Millet
   • Sorghum Family
     • Sorghum and Sorghum-Sudangrass
     • Sudangrass
   • Forage Brassicas: Forage Rape, Kale and Stubble Turnips
   • Annual Ryegrass
     • Italian Ryegrasses
     • Westerwold Ryegrasses
3. Characteristics of Annual Forage Crops in Ontario - Table 5-2
4. Update on Forages: Annual Species
5. Related links...

Annual Forages

| Winter Cereals (Rye, Triticale, Wheat) | Spring Cereals (Oats, Barley, Triticale) | Cereal-Pea Mixtures |
| Forage Soybeans |

The main annual crop that is used to provide forage is corn, which is harvested as corn silage. See the section Selecting Hybrids for Silage for more details.

There are several options for annual forage crops. They can be part of a planned cropping program or an emergency remedy to provide feed when perennial forage crops are winterkilled or in short supply. Annual forages are a valuable source of hay, pasture, silage or green feed.

Winter Cereals (Rye, Triticale, Wheat)

Fall rye, winter triticale and winter wheat can provide fall and early spring grazing. Adequate nitrogen fertility in the spring will provide good stored feed yields by late May. Feed quality decreases as the crop matures. Fall rye can be grazed in the fall if seeded between August 15 and 31. It will be ready for grazing 7 weeks after seeding. Fall rye will produce a larger volume of spring forage than winter triticale or wheat. Rye to be spring grazed should be fertilized with 50-80 kg/ha of nitrogen just before the rye turns green in the spring. Rye will begin to head out after mid-May if not grazed closely.

Winter triticale can be seeded at a similar time to fall wheat. Winter triticale seed can be difficult to source. Seed winter triticale at 100-125 kg/ha. Fertilize early in the spring with 80 kg/ha of nitrogen for spring grazing or stored feed. Winter triticale provides early spring grazing similar to fall rye.

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Spring Cereals (Oats, Barley, Triticale)

Spring cereals are very adaptable for forage production. Oats and barley are used extensively as companion crops for perennial forage seedings and are usually harvested for silage. Cereals can also be used for hay or pasture.

Cereals can be seeded at any time in the season. Early spring planting promotes maximum yields and production. Nitrogen fertilizer enhances vegetative growth, and therefore 30-50 kg/ha of nitrogen are recommended. Cutting or grazing can usually begin 6-8 weeks after seeding. Forage quality drops quickly after heading, so harvest at the late boot to early heading stage to maximize feed value. Yield will increase as plants mature, but feed quality drops dramatically. Silage should be wilted to 50%-65% moisture.

Cereal silages are higher in protein than corn silage but usually lower than good-quality alfalfa haylage. Energy values are lower than corn silage and often comparable to alfalfa haylage.

Oats are preferred over barley for pasturing and hay due to their higher palatability. Mixed grain and spring wheat can also be used for forage.

For more information on spring cereal mixtures, refer to the OMAFRA Factsheet, Forage Production From Spring Cereals and Cereal-Pea Mixtures, Order No. 98-041, or visit the Web site at www.omafra.gov.on.ca/english/crops/field/forages.

Cereal-Pea Mixtures

Field peas seeded in mixtures with cereals will enhance feed quality. Pea mixtures can increase protein levels and improve feed digestibility if the peas make up at least 50% (by weight) of the seed mixture. This will increase seed costs. Forage pea varieties are preferred. Avoid using a semi-leafless pea variety in order to maximize leaf yield. Oats with peas may be used as a companion crop for seeding alfalfa but should be harvested for silage. Cut as the oats are heading out; the peas will be just starting to pod. This growth stage will typically occur around the last week of June.

Mixtures of spring triticale and peas can be grown as a forage crop. Seeding rates and crop management are similar to that described for oats and peas. Mixtures of triticale and peas usually have more peas in the harvested forage than mixtures of oats and peas. This tends to increase quality but makes wilting slower and increases the length of time the crop must cure before ensiling.

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Forage Soybeans

Soybeans are primarily grown in Ontario for oilseed production. However, soybeans may provide a source of high-quality forage as an annual crop. Whole plant soybeans with good pod formation will have similar protein levels and digestibility to alfalfa. Soybeans can be harvested for silage but are difficult to cure for hay.

Plant height and branching ability should be taken into consideration during variety selection. Forage soybean varieties have been developed. A solid-seeded planting with a grain drill at a seeding rate of 80-100 kg/ha will provide a productive canopy for forage production. Very few herbicides are registered for use on soybeans harvested as forage. Check herbicide labels for use restrictions. An alternative would be to use a rotary hoe 7-10 days after seeding to reduce weed competition. Refer to the section Mechanical Methods of Weed Control in OMAFRA Publication 75, Guide to Weed Control. Harvest of soybean forage should take place just as the lower leaves on the plant are beginning to yellow. In Ontario, this usually coincides with the first week in September. Only one cut per season is harvested (Order OMAFRA Publication 75, Guide to Weed Control)

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Warm-Season Annual Grasses

Members of the sorghum, sudangrass and millet families are semi-arid, tropical, warm-season annual grasses. Warm-season annual grasses are often considered in emergency forage situations where alfalfa has winterkilled, or when planting has been delayed. They offer advantages over corn silage in that they can be grown with conventional forage seeding and harvesting equipment. They can be used in Ontario for silage (chopped or wrapped large bale), green chop or pasture. Haying of sorghums and sudangrass is not recommended because they are difficult to cure. Millet is frequently used as haylage or possibly hay, with good drying conditions. Sorghums and sudangrass should not be fed to horses, as they can cause cystitis, an inflammation of the bladder. Refer to OMAFRA Publication 19, Pasture Production. (Order OMAFRA Publication 19)

Millets

The name "millet" has been given to numerous grasses with small edible seeds. Most millet types, including Japanese, proso, foxtail, barnyard, Koda, finger and Teff, have short (0.3-1.2 m or 1-4 ft), slim stalks. Pearl millet is the exception to this description, with stalks over twice as long (1.5-3 m or 5-10 ft) and thicker. The millets commonly used for forage in Ontario are pearl millet and Japanese millet. With proper management, millets can produce forage with very good quality.

Millets have a smaller stem than sorghum grasses and slightly higher total digestible nutrients (TDN) and protein levels. Millets may be preferred over some sorghums for pasturing or green chop because they do not contain prussic acid. Millets and sorghums can be easily damaged by grazing and therefore should be strip grazed.

Pearl Millet

Pearl millet grows with a mass of very fine fibrous secondary roots and tillers. It exhibits drought tolerance and prefers a lighter sand or sandy loam. Sorghums will yield better on heavier soils. Pearl millet can be planted when there is no risk of frost and when soil temperatures are 12°C (54°F) or warmer. While the last week of May or early June is typically the best time to seed, planting can be delayed until the first of July. The recommended seeding rate is 9-20 kg/ha at a 1-cm (1/2-in.) planting depth.

Quality and quantity of forage produced will be determined by the stage of maturity when harvested. For high feed quality, first cut is usually ready about 55-60 days after planting, when it is still vegetative. Second cut is ready about 30-35 days later. Leaving at least 10 cm (4 in.) of stubble results in faster regrowth. When grazing, leave about 15-20 cm (6-8 in.) of stubble for faster regrowth.

To achieve high yields and protein levels, forage pearl millet will require more nitrogen than the older millet varieties, but exact rates have not been determined. Growth habits and yields of forage pearl millets are similar to those of sorghum-sudan hybrids. A split application of nitrogen, half at seeding and half after the first cut, will optimize yield and quality. For weed control, refer to OMAFRA Publication 75, Guide to Weed Control. (Order OMAFRA Publication 75)

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Sorghum Family

Members of the sorghum family used for forage include forage sorghums, sudangrass and various hybrids. There is considerable variability in agronomic and nutritional quality traits among species, hybrids and varieties.

Sorghum and Sorghum-Sudangrass

Forage sorghum and sorghum-sudangrass grow tall and have the potential for high yields. Older forage sorghum varieties were adapted to a high yield, lower forage quality, single-cut harvest. Grain sorghums, also called milo, are not recommended for forage production due to low dry matter yields.

Newer forage sorghum hybrids have been developed to be grown as a short season, two-cut, high-quality forage. Hybrid forage sorghum has fine fibrous secondary roots and tillers, giving it drought tolerance characteristics. Forage sorghum will tolerate heavier soils better than pearl millet. Optimum growth of these plants occurs under hot, moist conditions.

Planting of forage sorghums should be done after the risk of frost has past and soil temperatures are above 12°C (54°F), typically the last week of May or early June. Recommended seeding rates are 15-20 kg/ha at a 1-cm (1/2-in.) planting depth. Fertilize with phosphorus and potash according to soil test. The nitrogen recommendation is 50-100 kg/ha. A split application of nitrogen, half at seeding and half after the first cut, will optimize yield and quality. For weed control, refer to OMAFRA Publication 75, Guide to Weed Control. (Order OMAFRA Publication 75)

The stage of maturity is the most important factor influencing the quality and quantity of forage produced. Typically, forage sorghums are ready for harvesting 60-65 days after planting (late July or early August) and a second cut will be ready 30-35 days later. For a faster recovery of aftermath growth, leave at least 10 cm (4 in.) of stubble when cutting, or 15-20 cm (6-8 in.) when grazing. A one-cut silage system will greatly improve yields but at the expense of feed quality. Feed quality drops dramatically after heading. The crop should be wilted and ensiled at about 65% moisture content.

Forage sorghum varieties with brown midrib (BMR) characteristics are being developed with increased fibre digestibility. BMR is a genetic mutation that reduces the amount of lignin in the stalk and can also increase lodging.

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Sudangrass

Sudangrass is used for pasturing. It has pencil-size stems and is palatable even after it heads out. Grazing should be delayed until the crop reaches 45 cm (18 in.). Under rotational grazing, the crop will remain productive and succulent throughout the season. Sudangrass can tolerate slightly wetter soils than the other sorghums but does best on medium to well-drained soils.

Prussic acid poisoning is a possible concern if feeding sorghums, particularly with younger or frosted plants. Sorghum and sudan grasses can cause prussic acid (hydrogen cyanide) poisoning in livestock. Young or immature plants, plants suffering from drought or plants that have been frosted contain a higher level of prussic acid. Short-season areas are at greater risk of frost. High-nitrogen fertilizer also increases the potential toxicity. Some newer hybrid forage sorghums may have an advantage in lower levels of prussic acid potential. To reduce the risk of prussic acid poisoning:

• Do not graze pastures or green chop stands less than 45-60 cm (18-24 in.) tall.
• Do not green chop or ensile sorghum over 76 cm (30 in.) tall for 3 days after a killing frost.
• Do not green chop plants under 45 cm (18 in.) tall for 3 weeks after a killing frost.
• After a drought, do not graze animals on new growth following a rain.
• Use varieties with reduced prussic acid content.

Prussic acid poisoning is not a concern with millets.

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Abnormally high nitrate levels in forages can lead to nitrate poisoning and even death in livestock, and formation of silo gas if the crop is ensiled. Of the various forages, sudan-sorghum and cereals can accumulate the highest levels; forage grasses accumulate intermediate levels; while legumes accumulate levels low enough to rarely be considered a problem. Nitrate poisoning can also be a concern with green chop corn and corn silage.

Nitrate levels are only a problem under abnormal growing conditions, with the following situations the major concern:

• Very high soil levels of nitrogen, due to excessive rates of nitrogen fertilizer or manure or combinations of these along with legume plowdown.
• A long drought, followed by rain. In this situation, delay harvest for 10 days after rainfall, to allow conversion of nitrates to protein.
• Any condition that kills the leaves, while roots and stems remain active and accumulate nitrates (such as frost, hail and sometimes drought).

Suspect feeds can be tested for nitrate levels. Ensiling will reduce the nitrate level in the forage. Note that when high nitrate forage is ensiled, deadly nitrogen dioxide gas can be produced (see the section Silo Gas).

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Forage Brassicas: Forage Rape, Kale and Stubble Turnips

Forage rape, kale and stubble turnips are excellent crops for providing high-quality pasture from September to December. Refer to OMAFRA Publication 19, Pasture Production, for more information. (Order OMAFRA Publication 19)

Annual Ryegrass

Annual ryegrass is a rapidly growing bunchgrass that is adapted to a wide range of soil conditions. It regrows continuously throughout the season and has the potential to be highly productive if it receives enough rain and nitrogen. It is a useful species for mid- to late-season production but does poorly under high-temperature conditions. During periods of little or no rainfall, the plants stop growing and may die.

Two types of ryegrass of differing growth habits are available.

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Italian Ryegrasses

The Italian ryegrasses are short-lived perennials, but under Ontario winter conditions behave like an annual. The Italian ryegrasses remain vegetative, producing a lush, leafy growth that doesn't usually grow taller than 40 cm (16 in.). They are difficult to use for making hay.

Westerwold Ryegrasses

The Westerwold type is a true annual and grows to 40-80 cm (16-32 in.) high, making it suitable for pastures or hay crops. The Westerwold varieties grow taller, produce stems and are therefore easier to hay. Cut before or just at the heading stage. Feed quality decreases rapidly after heading.

Seed in early spring at a rate of 20-25 kg/ha using a drill or cultipacker-type seeder. The seed should be placed 1 cm deep and the seedbed rolled to ensure good emergence from the light, fluffy seed.

Table 5-2. Characteristics of Annual Forage Crops in Ontario summarizes the characteristics of annual forage crops grown in Ontario.

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100 kg/ha = 90 lb/ac

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Updates on Forages: Annual Species

No updates available at this time.

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Related links...

• Forages
• OMAFRA Publication 19, Pasture Production

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