When seeding forages into cultivated land, the success of establishment is seen by many as a "risky" or an "environmentally sensitive" crop that requires luck to be successful. The experience Ducks Unlimited gained by seeding over 30,000 acres on hundreds of different fields shows that luck does not enter into the equation. Forage seeding is not an art rather it is a science. There are rules to follow and if the rules are compromised, so may the success of the forage establishment.
A general rule to follow for forage establishment is:
By choosing the correct field, selecting the correct forage species and following some basic rules for seeding, forage establishment can become relatively risk free.
One the first factors to investigate when deciding to convert cultivated land into forage is knowing the condition of the field. By doing some field history, one can gather information to help decide what forage species to use, when to seed, what equipment to seed, what weed control is required and whether or not to use a cover crop.
Some basic questions one should answer are:
By knowing the condition of the field, one can assess if the cultivation should be converted to forage immediately or if other management practices are required prior to seeding.
Another factor one should consider is how the forage is to be utilized. It should not be as simple as to seed an "alfalfa and brome" mixture on all of the acres to be converted. Just as with difference with annual cereal crops, such as wheat and barley, forages species are just as different with their end use and growing characteristics. One should consider the intended end use of the forage and select the correct forage species to satisfy the use.
Questions one should ask themselves are:
Once you have decided on the field location and the end use of the forage, one can determine
what species should be used and then the establishment process can begin.
One requirement prior to the actual seeding operation is to have a firm seedbed to ensure good seed to soil contact. In addition, a firm seedbed will aid in controlling an accurate seeding depth. By direct seeding the forage into standing stubble, the land is moist and firm thus creating an ideal environment for forage establishment. If tillage is required prior to seeding, ensure the land is packed. Another option on cultivated land is to delay the seeding until rain can pack the soil thus ensuring a firm seedbed.
Due to the small size of forage seeds, proper depth of seeding is critical. Improper depth is probably the greatest reason for establishment failures. Most forages should be seeded at a depth between ½ to ¾ of an inch. Do NOT seed to moisture. Direct seeding the forage into standing stubble at a shallow depth is one way on achieving both correct depth and seeding into moisture.
Our experience has shown the earlier the forage is seeded, the better the chance of stand establishment. Seeding earlier increases the chance of receiving moisture as well as improving the competitive capabilities of the forage against any weeds. Early seeding does not apply in all circumstances. If the field to be seeded to forage has a perennial weed population, seeding should be delayed to allow for weed control. There are consequences by delaying the seeding. If a companion crop is used, it may have to be used at a lower seeding rate, changed to another companion crop or totally removed from the blend. To aid in seeding the forage early in the season, one should consider a pre-harvest application of glyphosate in the previous growing season. This will help in cleaning the field and allowing an earlier seeding date for the forage the following year.
Other seeding dates available to a producer are early August (prior to August 10) or dormant seeding in October. We have limited our seedings in early August to flood prone land. These lands tend to dry up too late in the year (late June) and rather than risk seeding in a hot, drier time period in the season, an early August seeding is able take advantage of cooler and moister conditions. Dormant seeding in October occurs when the temperature of the soil is less than 5 degrees Celsius. Providing adequate weed control has taken place, dormant seeding has worked very well for us. The benefits of seeding in October are the forage is enable to take advantage of the moisture and low competition in the spring. In some years, we have been able to take a cut of forage in August. One drawback of dormant seeding, is if a cover crop was used, it normally winterkills and does not provide revenue the following season.
All types of seeding equipment can be used to seed forages, providing one does not compromise the seeding depth, firm seedbed and excessive drying of the soil. That being said, there are pieces of seeding equipment which do a better job than others for controlling depth and maintaining a firm seedbed after seeding.
Zero tillage equipment, in my opinion, has removed a great deal of the risk of seed forages. This equipment is designed to place seed shallow and directly into a moist firm seedbed which are all beneficial to forage establishment.
Double disk press drills are able to achieve an accurate depth of seeding, providing the land is firm, however the amount of trash they are able to penetrate is limited. Hoe drills and cultivators are able to clear a lot more trash than press drills, however they can compromise the depth of seeding.
Broadcasting and harrowing forage seed is a common practice in the Parklands and can be successful. This method of seeding is also the riskiest. Accurate depth, improper packing, excessive drying of the soil and excessive weed growth are the main reasons we do not utilize this seeding method.
Air delivery systems can be used for seeding and should not necessarily be avoided. Certain forage species require a very low seeding rate (<1 lb/acre) or may tend to cause bridging either in the tank or air tubes. These characteristics for some forage species create a risk of improper metering of the seed with air delivery systems. There are some tanks which have built in adjutators to remove the problem. Other solutions include mixing the seed with a carrier (cracked wheat, vermiculite, companion crop), have the seed de-bearded, or use a seed coating. Air systems are not a problem with seeding forages and the majority of the forages seeding by Ducks Unlimited use an air delivery system.
There is not one single row spacing recommendation for all forage plantings in Saskatchewan. Based on the type of forage, the end use and the soil zone will help in determining the ideal spacing for the forage stand. A general rule to follow is the drier the area, the wider the spacing. With the wider row spacing on some the newer equipment, producers should be aware that in some circumstances, the row spacing may too excessive and could be a source for weed invasion in forage stands.
To ensure a healthy and competitive stand of forage, the proper plant density must be achieved. Proper calibration should be carried out for all crops not just for forages. As previously discussed, forages are lighter and can cause bridging within certain seeding equipment. Once an accurate metering has been achieved (bare forage seed, blended seed or coated seed) there are two methods to determine seeding rate, Calibration by weight or counting seeds per foot of row.
Weigh the seed metered out for a fraction of an acre and then calculate the rate per acre. The following procedure is based on 1/50th of an acre.
| Drill Row spacing in inches | Distance to seed 1/50th acre(ft) with six rows |
÷ |
Circumference of Drive Wheel (feet) |
= |
Revolutions of Drive Wheel to seed 1/5th acre |
|
6" |
290' |
÷ |
C |
= |
X |
|
7" |
249' |
÷ |
C |
= |
X |
|
8" |
218' |
÷ |
C |
= |
X |
|
9" |
194' |
÷ |
C |
= |
X |
|
weight of seed collected (in ounces) x 50 16 |
= pounds per acre |
Calibration by Counting Seeds Per Foot of Row:
Adjust the repeat steps in 6 & 7 until the desired rate is achieved.
As with annual crops, forages are susceptible to weeds. Pending the end use of the forage (hay for export, seed, etc) your tolerance for weeds should be adjusted accordingly. Perennial weeds in a forage stand can be very detrimental and could ultimately reduce the life span of the forage. Perennial weeds such as quachgrass, Canada thistle, sow thistle, dandelions are weeds we have found to be too competitive on seedling forage plants. In addition, there is very limited in-crop weed control options within forage stands. Based on these perennial weeds present in a field, we will either crop the cultivation for another year or chemically fallow the land and use herbicides to control the perennial weeds. Annual weeds are less of a concern after the stand is established, however, they must be addressed in the establishment year. These weeds can be addressed through mechanical means, such as mowing or haying, or through herbicides. In my experience in the Parklands, the only annual weeds we will aggressively control with herbicides are green foxtail, wild buckwheat, kochia, and excessive amounts of volunteer canola or wild mustard. For a complete list of registered herbicides for forages, consult the provincial weed control guide. Some concerns to be aware of when applying herbicides on establishing forage stands are; to be aware of the feed restrictions with herbicide residues, and the potential injury to one of the forage species in a blend (alfalfa or grass).
Insects are also a risk to forage plantings. Grasshoppers have been the major pest, which can severely injure or cause a planting to fail. Producers should be aware of any high areas of infestation in the province and be prepared to control grasshoppers. If the grasshopper numbers are above the threshold and if the grasshoppers are present when the forages are early in their establishment year, management should occur. Consult the provincial weed control guide for the appropriate registered insecticide.
Once the decision has been made to use a legume as part of a forage blend or a pure legume stand, proper inoculant must be used. There is not a single strain of inoculant available for all legumes. Ensure the correct inoculant is used and applied to the seed. There are different means to adhere the inoculant to the seed, such as self-adhesive brands or an addition of a sticking agent to have the inoculant attach to the seed. The easiest method for inoculation is to have the seed be pre-inoculated. Inoculation is a must for legumes and one must ensure all legumes receive the correct strain and application prior to seeding.
Most producers will want to receive some revenue in the year of establishment of the forage and will often utilize a companion crop. Companion crops are another source of competition for the establishing forage and may cause injury to the forage. To lessen the effects of companion crops, producers should select the least competitive crop (flax, oats, wheat, barley, canola, in that order). Reduce the rate of the companion crop to approximately ¼ to ½ of the normal seeding rate. Do not seed the companion crop in the same drill row as the forage. Try seeding the forage at right angles to the companion crop or alternate rows. Remove the companion crop as early as possible after heading preferable as hay or silage. Remove the bales as quickly as possible. If the companion crop is removed as grain, ensure straw and chaff are manage adequately with the combine. Forage seedlings are easily smothered by chaff and straw. Leave tall stubble to protect the forage and to trap snow over winter.
Forage stand evaluation should take place 4 to 6 weeks after seeding. During the growing season, one should be assessing the amount of competition from weeds and from the companion crop (if used) on the forage. In addition, one should determine if the stress is environmental, such as drought. If either pressure is severe on the forage, management should occur to remove or minimize the stress on the emerging forage.
Forage seedlings are often difficult to see and judging whether the stand is successful should be carried out in fall of the establishment year or the following spring. The goal of seeding is to have 3 to 4 forage plants per foot (pending species and end use). If the entire stand or areas of the field appear to be low in plant number, there are some limited options to improve the stand. One can consider broadcasting some fertilizer to encourage forage growth to thicken the stand. Another option is to zero till additional grass seed in the bare areas. Any area not producing forage is not providing revenue and is a possible source for weed infestation.
Ducks Unlimited has been encouraging forage production in areas of high wetland densities within the province to provide much needed nesting cover for waterfowl in the spring. In the past few years, there has been new interest in forage and producers are realizing that forages are profitable on more than the marginal land where forages have traditional been restricted to. For producers who would like to seed forages, establishment is not that difficult or risky. By following the basic agronomic principles for forage seeding, one is able to "stack the deck" in their favor and remove the gambling of successful forage establishment.
Alberta Forage Manual. 1981. Alberta Agriculture
Dryland Perennial Forage Establishment. 1992. Ducks Unlimited. Agriculture Canada, PFRA