Ministry of Agriculture

Direct Seeding for Perennial Forage Crops

     Prepared by E. L. Moore, P.Ag.


Introduction

Much of the farmland in the North Central region of B.C. is located on sloping land that experiences intense runoffs during snow melt and intense rainfalls (spring and fall). Exposed soil during these runoff events are subject to erosion and the resulting soil loss is evident as gullies in fields or in some cases, as sediment buildup in ditches next to fields. The amount of soil loss can be high, in some cases soil loss can be several tonnes per acre. Direct seeding and minimum tillage are two popular ways of minimizing soil loss.

Soil conservation has become popular in the grain growing areas of western Canada and numerous research and demonstration projects have been established over the years to assist producers interested in soil conservation. While most of this research and demonstration work has been done on cereal and oilseed crops, direct seeding of perennial forage crops has just recently been attempted. From experiences in BC direct seeding of forage crops can be successful provided that proper agronomic steps are taken. In most situations direct seeding will contribute to the improvement of soil structure while maintaining crop yields, minimizing soil loss and conserving soil moisture.

This publication will outline some of the requirements needed to successfully direct seed perennial forage crops.

Planning

One of the first things potential direct seeding farmers must contend with is planning the crop rotation. Consideration must be given to existing crops and vegetation, future crops, and potential weeds problems in order to plan a successful seeding program for your field.

If forage crops are desired, the need for preparing the seedbed is important.

Field Assessment

It is very important to scout the fields prior to making any management decisions. Unforeseen problems can usually be avoided if this is done. Making notes about herbicide, fertilizer, time of seeding, soil conditions, weed problems encountered can be a valuable asset when rejuvenating an old stand. It can provide you with information that may save time, money and frustration in the future.

A field assessment should take place in the fall and spring to evaluate what weeds and vegetation are present. A heavy winter annual weed problem that is identified in the fall and control measures taken, can reduce time required in the field prior to spring planting.

Take notes about the species of perennial vegetation and approximate density. This may seem time consuming but it will play an important role in determining the best time to apply glyphosate (Roundup, Touchdown, Victor). For example, bluegrass species should be controlled when in the 3-4 leaf stage, the height will be about 4 inches tall, quackgrass should be about 8 inches tall when control should be taken. If the predominant species is quackgrass then the stand should be left to grow to 8 inches; if the predominant species is bluegrass then the field can be sprayed when it is about 4 inches tall. From experiences in the Smithers district usually two applications of glyphosate are required, the first being 2 litres/acre (either in the fall or spring) and second usually at the 1 litre/acre rate (usually applied in the following spring).

Crop Rotations

One common method for establishing a forage stand with direct seeding has been to spray the forage stand in the spring or fall with a two litre/acre rate of glyphosate then seed the field down to a grain crop for one year. This method does the following:

  1. Eliminates the existing poor producing stand of forage
  2. Controls any perennial weed problems
  3. Helps break up the heavy sod usually associated with old hay fields.
  4. Helps prepare "mellow" seedbed for forage seeds
  5. Annual grain crop can be harvested for grain or as forage.

The following spring a ½ litre/acre to one litre/acre rate of glyphosate is used to control escaped perennials and winter annuals that have established. Forages are then seeded with a grain cover crop. This method has been proven to work provided proper sprayer calibration and herbicide application has been done and competing vegetation is successfully controlled.

A second method which has not been used on a large scale is to spray an existing forage crop about 5 to 7 days prior to harvest, then harvest the forage material as silage or hay (provided proper weather conditions are present), the field is left fallow till the next spring where winter annuals are controlled by a one litre/acre rate of glyphosate, or if conditions are right, seeding could be done in the fall.

This may reduce the need for a grain crop and speed up the rotation time for establishing forage crops. Breakdown of the sod is accomplished through the winter and the site should be ready for seeding in the spring.

Vegetation Control

Good control of existing vegetation is extremely important. Poor control of existing vegetation severely reduces establishment of forages and cereals. Anywhere from a 50% to 100% failure has been the norm when fields have been seeded without controlling the existing vegetation with glyphosate. When considering the cost of fertilizer and seed at about 60-70 dollars per acre plus time, fuel and machinery maintenance unsuccessful forage establishment is expensive. It pays to calibrate the sprayer and to understand the product you are using. Read the Label!! prior to applying the product; it may not be the right product for your needs.

Winter Annual Weed Control

With the reduced cultivation in direct seeding, winter annual weeds can flourish. They can be a problem in forage stand establishment using zero tillage if unchecked, but they are easily controlled. Winter annual weeds germinate in the fall, produce small rosettes, overwinter, and produce seed the following year usually in the months of May and June. You may be familiar with the following winter annual weeds common to the area.

  • Stinkweed (Thlaspi arvense)
  • Shepherd's-purse (Capsella bursa-pastoris)

Strategies for Controlling Winter Annual Weeds

Late fall and very early spring control measures are usually very effective in controlling winter annuals. The late fall herbicide applications are usually very effective as this allows any winter annuals to germinate prior to herbicide treatment. Winter annuals can be controlled in the spring as well, provided they are sprayed prior to bolting. This usually occurs very early.

Herbicide options for controlling winter annuals depend on the crop to be planted. Please consult your Field Crop Guide to determine the proper herbicide recommendations.

Dandelion Control

We recommend the addition of 1 litre/acre of 2,4-D Amine to 2 litres/acre of glyphosate as a tank mix to control heavy infestations of dandelions. It is often a necessary addition as a fall treatment and must be done as late as possible (even up to freeze-up) to ensure the maximum number of winter annuals have germinated. Most producers don't watch weed growth early enough in spring and hence weeds often get beyond optimum growth stage for effective herbicidal control. Spring applied 2,4-D, prior to seeding alfalfa, has had negative effects on alfalfa establishment. Do not spring apply if seeding alfalfa.

If dandelions are present in significant numbers, it may be best to go with the one season of annual crop rotation method. If dandelions are small and not long established, you could wait for glyphosate as a spring application timed with winter annual control but this would have to be done very early!! Light infestations of dandelions may not need control as the new forage stand should compete with the dandelions.

Seeding

Seed Placement Proper seeding depth is very important. Forages and fine seeds should be seeded no more than ½ inch deep. Grains should be seeded at approximately 1-1/2 to 2 inches, Grains are more capable of overcoming deep seeding than are forage seeds.

Proper seed placement is Crucial!! Get off the tractor and find out where the machine is placing the seed. Make adjustments if needed. Heavy trash cover or dense sod can cause poorly adjusted seeding equipment to place the seed on top of the soil which results in poor emergence.

Time of Seeding Cereals can be seeded immediately after glyphosate treatment. However, if you are seeding a forage crop back into a hay field which has had no previous tillage or herbicide treatments allow at least a three week time period after glyphosate application before seeding. Best results may be to do a fall treatment of glyphosate and seed the following spring.

Seeding Rate No change in rate is required with direct seeding. Refer to the publications listed in the reference section for recommended varieties and seeding rates for forage and cereals.

Trash Removal

If there is very much trash on the surface of the soil, it is important to remove this, either by grazing or mechanical harvest. In Kamloops there have been a number of trials where stand establishment on the field area that was grazed was superior to the side that was not grazed.

Another method which may deal with trash cover is to treat the existing crop which is to be renovated with glyphosate then following label directions harvest the material as you normally would. This should provide adequate trash removal.

Fertility

Fertilizer use is important, not only for the growing crop but also to aid in the breakdown of the organic matter left behind from the herbicide treatment. On cereal and perennial grass crops an additional 30 to 40 pounds of nitrogen/acre should be added to the fertilizer you would normally apply. This seems to aid in the establishment of the new crop and assist in breakdown of the dead sod. From our experience this is needed only the first year of direct seeding.

References and Articles

Several publications are available for producers interested in direct seeding. These publications are an excellent source of information whether you are already using direct seeding or are just beginning.

  • "Conservation Tillage Manual" - published by the Peace River Soil Conservation Association, contains articles on fertility, crops and rotations, equipment, weed and pest control and economics. Contact the BC Ministry of Agriculture and Lands in Dawson Creek, 250-784-2601 for ordering information.

Crop Recommendations


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