Annual Crops To Manage Unseeded Acres

Green Manure

Planting green manures is an option for reducing inputs for future years. Using legumes to fix nitrogen will reduce fertilizer inputs for the following season and improving soil conditions. Many legumes are useful for improving soil conditions (ex: organic matter, drainage, erosion, weed density, fertility), however, choose your legume carefully.

Red clover is the best fit for quickly establishing low lying or saturated soils, and yellow sweet clover is a good option for coarse textured and drier soils. Red clover and sweet clover are short lived perennials used in many zero-till and in organic production systems for improving soil conditions and adding nitrogen to the system. Red clover establishes easily and tolerates wet and acidic soils, much more than alfalfa and although a perennial plant, it has the poorest winter hardiness level among the forage legumes, therefore, volunteers should be minimal after a few years of annual production.

Sweet clover is a biennial plant (lasting 2 years) that produces only forage in the year of seeding and forage plus seed in the second year of growth; therefore, volunteers should also not be a concern if tilled in the same year as planting. If planning on grazing the summer growth, it is important to choose low coumarin varieties of sweet clover, and to be cautious of the boat potential in red clover.

Some livestock producers have also had great success in seeding the two clovers together at an 80% sweet clover with 20% red clover mix. For hay producers, the sweet clover can double hay yields produced by alfalfa and quicken dry-down. For annual croppers, the extra tonnage of sweet clover adds tremendous amounts of soil organic matter, improving soil tilth, drainage and fertility.

Variety Selection

Red Clover: Single cut red is most commonly used for non-hay production systems as it does not readily set seed in the year of seeding and is less winter hardy than double-cut.

Sweet Clover: If planting sweet clover as livestock feed, use low coumarin varieties. Coumarin is a substance present in varying amounts in all sweet clover species. Two varieties of sweet clover, Norgold yellow sweet clover and Polara white sweet clover have very low coumarin content and do not pose a problem when feeding livestock.

Fertility: General recommendations for production are 55 to 75 pounds per acre of phosphorus, 55 to 150 pounds per acre of potassium, and 30 pounds per acre sulphur for establishment. You should base fertilizer applications on soil test results, ensuring you do not exceed provincial regulatory guidelines.

Seeding: 7 to 10 pounds per acre will provide a good stand with good nitrogen fixing capabilities. Harvest dates: Till clover into the soil prior to freeze up.

Cost/Benefit: The cost of the adding clover seed is off-set by the nitrogen produced for next year's crop. Seed cost range from $2.50 to $3.50 per pound for common and certified seed; resulting in an average seed cost of $17 to $35 per acre. The amount of nitrogen contributed by red clover can range from 30 to 50 pounds per acre and for sweet clover from 50 to 100 pounds per acre by full bloom, depending on the density of the stand, moisture availability, soil type and the length of the growing season. This is comparative to some Manitoba studies on field peas showing a nitrogen benefit of 31 pounds per acre.

Nitrogen Benefit Information


Green Feed Options

Barley, Oats, Winter Wheat, Fall Rye

Planting annual crops such as barley or oats for green feed is an option for late season planting. They can provide high energy feed for livestock within a short period of time. They can be harvested at the early to soft dough stage for stored feed, or they can be swathed and left for late season swath grazing. Barley and oats can also be used as a summer pasture within 4 to 6 weeks of seeding, however, it is important to graze above plant growing points to maintain quick regrowth. If moisture removal is the main objective this summer, harvesting the crop as green feed, silage, or swath grazing is recommended. Post-harvest regrowth can also provide late season grazing; however, regrowth is dependent on sufficient moisture availability. Fertile soils can provide excellent late season grazing well into October.

Winter cereals are an option for producers wishing to graze the stand during the summer and late into the fall period; fall rye and winter wheat are typically used since their regrowth is much better than spring cereals. Winter cereals are not the best option for producing green feed or silage because they require an over wintering period to produce tillers. They are also not as capable of de-watering a soil in the year of seeding as a spring cereal.

Seeding: Use the same principles as for grain production. In some cases, seeding rates are increased by 10-20% to increase stand density. Oats seeded at 1.5 to 3 bushels per acre or barley at 2 to 3 bushels per acre is a good place to start.

Fertility: Proper fertility management is recommended to maximize forage production. When seeding late, reduced fertility levels can be used. This will also minimize potential nitrate issues in the feed. If winter cereals are planted, split applications are recommended to provide season long fertility.

Intercropping: Spring seeding a spring and winter cereal together is a good option for providing a season long forage option. Harvest the spring cereal as silage and use the winter cereal below for mid to late season grazing. Intercropping maximizes the number of plants per acre, nutrient utilization and thus has shown to produce overall more dry matter than planting each crop on its own. Barley and fall rye is an example. It is recommended to seed both crops at approximately ¾ the normal seeding rate (ex: 1¼ - 1½ bushels per acre each). This will provide even growth throughout the season. If more silage or early season grazing is preferred, then seed the spring cereal a bit heavier. If the spring cereal is seeded too heavy, it may restrict growth of the winter cereal underneath.

Disease: Annual forage producers need to be aware of some of the same disease issues faced by grain croppers when planting cereals for forage. For example rusts, septoria and wheat streak mosaic. It is not uncommon to spray silage or greenfeed crops with fungicides if disease pressures are high. If disease pressures are high enough, the increase in feed quality will pay for the treatment.

When to Switch From A Cool-Season To A Warm-Season Crop

It is important that all the factors are considered when deciding to switch cropping plans to include warm season crops (millet, sorghum, corn, etc). You should base your decision on the following factors:

  1. How late is the seeding date?
  2. What seeding equipment is available?
  3. What seed is available?
  4. Does the crop fit your rotation?
  5. What type of weed pressure is in the field?
  6. What is the type of climate?
    a. How many heat units do you receive in a given year?
    b. How long is your frost-free period?
    c. How much precipitation do you normally receive?
    d. What type of soil is being seeded?

If you are looking to use the crop planted as feed, it's important to ask the intended buyer what type of feed is most desirable (green feed, silage, or pasture).

Warm season crops are more efficient at converting nitrogen, carbon dioxide and water into dry matter than cool season crops (ex: barley, oats). Millets are a good option for harvested green feed and for swath grazing. There are many types of millet available in Manitoba and it is important to choose the right millet for your environment.

Millets are adapted to hot-dry conditions, and have produced excellent forage yields in Manitoba when hot July and August temperatures are experienced. However, during cool years, barley and oats will typically produce higher forage yields than millet. Therefore, in a typical Manitoba summer, barley and oats are lower risk forage producers.

Millets do well in a wide variety of soils, the exception being the extremes of the soil spectrum. Their shallow roots restrict water availability in extremely coarse textured soils, and limit their production on low lying water logged soils. Experience has shown that proso millets are generally more competitive early in the growing season than foxtail types. 

Seeding: Millets are small seeded species, therefore shallow seeding (½" to 1") is recommended. Proso millets are generally larger seeded than foxtail millets, therefore recommended seeding rates are higher. For forage production, proso millet seeding rates range from 20 to 25 pounds per acre and foxtail millets from 15 to 20 pounds per acre. However, for grain production these rates are reduced to 15 to 20 pounds per acre for proso millets and 10 to15 pounds per acre for foxtails. Increase in seeding rates by 25-30% will ensure proper stand counts during adverse conditions for germination and seedling vigour.

Fertility: Fertility requirements are minimal for all millets, especially proso types as they are prone to lodging. In normal seeding scenarios, proso millet fertility rates for forage production are similar to barley or oats, ranging from 50 to 70 pounds N per acre. Since foxtail millets are generally longer season crops, more nitrogen may be applied, however, this is only true in ideal growing conditions. Excess nitrogen fertilizer increases the likelihood of lodging and elevated nitrate levels in the forage. Having at least 15 pounds per acre of phosphorus available to the plant will strengthen seedling vigour and yield potential.

Hay or Grain Harvest

Since foxtail millets are longer season crops, they are more commonly grown for forage production in Manitoba compared to proso millets. As a result, seed of foxtail varieties are often more expensive to purchase compared to their proso counterparts, but can yield more forage as well.

Both foxtail and proso types are suitable for hay/green feed production, providing excellent quality feed when cut at the proper stage: shortly after heading. Foxtail millets often have thicker stems and a thicker waxy surface coating, both which slow dry-down time, but also make it a preferred crop for winter swath grazing.

Proper adjustment of hay and discbine rollers or using a macerator after cutting is recommended to increase dry-down and thus reduce the probability of getting rained-on hay. Millets can also be successfully ensiled if harvested at the proper stage. Ensiling may also reduce some of the problems associated with more mature plants. These physical characteristics have also made the millets successful swath grazing crops.

Disease: Millets, especially foxtail types, have also been known to act as hosts to wheat streak mosaic. Although a minor occurrence, wheat producers should be cautious when deciding to include millet in their rotation.

Insects: Hairy stems of proso millets tend to discourage grasshopper feeding. Farmer experience shows that corn borer can occasionally be a problem.

Other Resources

Species Variety Example Seed Color Days to head* Days to Maturity* Potential Seed Yield (lbs/ac) Potential Forage Yield (lbs/ac) Notes
Foxtail Millet
Setaria italica (L.) P. Beauv.
            Typically harvested for forage.
Red None known. "Common" Red 55-70 70-90 1500-2000 2200-3300 Medium thick stems. Often first to head.
Yellow Golden/German Yellow 75-90 95-110 CO, NE, WY:2270 CO, NE, WY: 4800 ND: 4800-5900 Thickest stems of the foxtails; broad leaves; poor seeding vigor. Good lodging resistance. Yielded 3800 lbs/ac forage during drought.
Yellow Golden/German - Strain R Pale yellow 80-100 95-120 N/A   Medium thick stems, more leafy than Golden German. Showing promise in Manitoba conditions. Low seed availability.
Yellow White Wonder Cream White 70-85 90-100 CO, NE, WY: 2500 CO, NE, WY:4900 Coarse stems, broad leaves, Late maturing, Showing promise in Manitoba conditions. Low seed availability.
Hungarian Hungarian Mixed- yellow, black brown 55-70 70-90 2000-3000 3000-6500 Stems are medium size. Not as productive for forage as Siberian.
Siberian Siberian Red (NE), Manta (SD) Red to orange 55-70 70-90 CO, NE, WY: 2450 CO, NE, WY:4490 ND:3000-6365 Shorter, medium thick stems. Often first to head. Good drought tolerance.
Proso/Hog Millet
Panicum miliaceum L.
            Typically harvested for grain.
White Dawn (NE), Minsum (MN) White 50-60 95 CO, NE.WY:1600 ND: 1200-1700 ND : 3000-5800 Bred in CO, NB, SD. Short, early maturing, medium sized seed. Fair lodging. Thick stem, less suited for hay, more suited for silage.
Red Cerise (NE), Early Fortune Red to orange 50-60 85 ND:1000- 1600 ND: 5000-8800 Bred in CO, NB, SD. Tall, early maturing, small seeded. Fair lodging, Yielded - 3000 lbs/ac during drought
Yellow/Gold/Amber AC Prairie Gold (MB) Yellow 50-60 75 MB: 2000-3500 ND: 4000-7000 Bred in AAFC - Morden.
Green/Gray Crown (MN) Grey to green 50-60 85-90 MB:2000-4000 ND: 4000-7000 Bred in MN - considered a Manitoba variety.
Pearl Millet
Pennisetum glaucum (L.)
MiHy 300, MilHiy 500   80-100 110-130 N/A ND: 6000-8000 Typically harvested for grain. Poor early vigour. Less forage yield than Foxtail. Issues with disease, lodging, palatability. Silage harvest is best option.
Japanese Millet Japanese, Shirohie grey 40-50 45-60 N/A AB: 2000-4000 Typically harvested for grain, except for US where it is used for forage. Heads are similar to barnyard grass. Best suited for eastern Canadian climate.
Finger Millet
Eleusine coracana
    90-120       Typically harvested for grain