Well established and managed pasture is potentially one of the most flexible forage crop options in the Upper Midwest. Pastures are adaptable to any size of dairy or livestock operation, and can provide substantial amounts of quality forage at low cost with good management. Proper establishment and subsequent management will greatly influence production and longevity of improved pastures. Establishment concerns include soil fertility, land preparation, seeding and weed suppression.
Assess Soil Fertility
Before establishing a new pasture, take soil samples for analysis from the site to determine if any nutrients are deficient. Be sure to indicate the type of pasture planned for the site so that fertility recommendations are applicable to the species you will be seeding. For more information on soil testing and analysis, please refer to UWEX Publication A 2100, Sampling Soils for Testing. Contact your local UW Extension Office for a copy or view it on the Internet at: http://learningstore.uwex.edu/pdf/A2100.PDF .
Once the soil analysis has been received, determine the appropriate types and amounts of fertilizer to use. For new pastures, pH may need to be adjusted to at least 6.5 when including legumes in the species mixture to be planted. Soil phosphorus, potassium, and sulfur levels may also need to be adjusted prior to establishment. If possible, apply lime, manure and/or fertilizers prior to any tillage activities or surface apply during the fall prior to a spring seeding to improve effectiveness and availability of the nutrients applied.
Soils should be tested every 3 or 4 years and additional nutrients applied as needed to maintain fertility levels once the pasture is established.
Seeding rate recommendations may vary based on site conditions, method of seeding and the number of seeds per pound for a particular forage species. Under marginal establishment conditions, or when using broadcast seeding methods, it may be wise to increase the seeding rate by 10 to 20 percent. Also, with smaller seeds, fewer pounds are needed to achieve a full stand, so a lower seeding rate is used on small-seeded species. However, small seed require careful seed placement, so adjustments may be necessary to the planting equipment used to produce the desired results.
To decrease chances of soil erosion, a companion crop such as perennial or Italian ryegrass (2 pounds per acre), or small grains such as oats (1 bushel per acre) may also be included with the seeding mixture. For pasture plant species grown in Wisconsin, seeding rate recommendations are listed in UWEX Publication 1525, Forage Variety Update for Wisconsin, which is updated annually and is available through your local UW Extension Office or can be viewed on the Internet at: http://learningstore.uwex.edu/pdf/A1525.PDF .
When purchasing legume seed, check to see if the seed is pre-inoculated with appropriate rhizobia bacteria and then maintain such seed in cool storage prior to planting. If seed is not preinoculated, purchase and apply the appropriate rhizobial inoculant(s) for all legumes that are included in your seeding mixture to ensure adequate nodule development and nitrogen fixation capacity. Keep inoculants stored in a cool dark place until use and follow label application directions.
For Wisconsin, pastures can be established in the early spring or late summer months. Spring planting takes advantage of residual winter soil moisture and the promise of a season of good
growing conditions, with potential to provide pasture later that year. A primary disadvantage of spring seeding is that weed competition is usually greatest in the spring months. This may be an issue for some pasture species which are slower to establish, such as reed canarygrass and kura clover.
Late summer seeding can be scheduled to follow winter wheat, rye, and or spring oats/pea crops that are harvested earlier in the summer. A disadvantage of late summer seeding is that germination will be at the mercy of fall rains to ensure good establishment prior to the onset of winter. This offset by the fact that there are fewer weed species that will germinate and compete with a new pasture seeding. Late summer seeding should be planned to ensure at least 6-8 weeks of forage growth prior to killing frost.
Seedling pasture stands have two primary requirements of the seedbed:
• A firm seedbed to allow precise placement and good soil contact with small pasture seeds
• Minimal competition from existing vegetation or weeds for sunlight and moisture
Proper preparation of the site is a critical step in establishment. The amount and type of land preparation varies with site and soil conditions, and equipment available for establishment.
Tillage is often the best choice if it can be accomplished with little chance for erosion, since it can be used to eliminate existing vegetation as well as develop an excellent seedbed. Compacted soils may require ripping, and this is best done in the fall when the soil is driest. Plow, chisel, disk, or harrow as appropriate to eliminate clods and firm the seedbed. If tillage is required, some operations can be done in the fall prior to a spring seeding and used to incorporate any lime or fertilizers needed to amend the soil.
If a no-till drill is available, little or no tillage may be necessary, although light tillage (disking) may still be desirable if the ground is rough or uneven. No-till drills open a furrow, place the seed in the opening and press the soil back into place and are particularly suited for areas where soil erosion is a concern. Prior to using a no-till drill, existing vegetation should be sprayed with appropriate herbicides or grazed very closely to reduce competition with the seedling pasture stand.
Methods of Seeding Pastures
Pastures can be established by drilling, broadcasting, or even aerial seeding. Development of a well-prepared seedbed through tillage followed by cultipacking is still the most consistently successful method of pasture establishment where topography and soil type allows it. While drilling or cultipacker seeder (Brillion seeder) into a prepared seedbed is generally the preferred method, broadcast seeding methods followed by harrowing and/or cultipacking the seedbed have also been successful. Seeding in two directions ensures the most uniform stands, but may not be cost effective or practical for hilly conditions, where machinery safety and potential for soil erosion may also need to be considered.
The goal is to uniformly sow the seed into a firm seedbed at the correct depth and seeding rate. This is most easily accomplished with a drill. The optimum seeding depth for most forage species is ¼- to ¾-inch, with the soil packed firmly around the seed. Some soils are difficult to pack, and new seedings may fail from drilling into a fluffy seedbed because seed placement is too deep and/or the soil dries too quickly. It is often necessary to use a cultipacker or similar device behind the drill to firm the soil around the seed. If the seedbed was prepared the previous fall, or has received some rain, packing behind the drill may be unnecessary.
Frost seeding is also an option in some situations. Most legumes can be frost seeded successfully, but frost seeding is only recommended for ryegrass (Italian or perennial) and orchardgrass. To frost seed, broadcast seed during the late winter period when Wisconsin has warm sunny days and cold nights that produce frost cracking of the ground. The broadcast seed falls into the cracks and germinates as spring conditions improve. The areas to be frost seeded should be either grazed or mowed closely at the end of the previous growing season.
Frost seeding works well for thickening thin pasture stands and to add legumes to the stand, but is not recommended for establishing new pastures. Research suggests that frost seeding is successful about 60% of the time due to variations in weather conditions from year to year. For this reason some producers plan to frost seed every year to create a pasture “seed bank”.
Fertilization after Establishment
If major nutrient deficiencies are corrected by preplant applications of sulfur, phosphorus and potassium, it is seldom necessary to apply additional fertilizer for initial seedling development in new pastures.
Most perennial grass seedlings are inefficient at using nitrogen, so applying additional nitrogen fertilizer early in seedling development only gives weeds a competitive advantage. Perennial grasses with a significant root system (as indicated by 6 – 8 inches of top growth) can use applied nitrogen efficiently if adequate soil moisture and growing season are left during the establishment period. Nitrogen applications should not exceed 40 to 60 pounds per acre at this stage of pasture development.
Weed Control During Establishment
Weeds can be managed using several methods, including biological, mechanical, cultural and chemical. Proper identification of weed species is critical as selection of the best management options is dependent upon the weed species present. If newly established pastures, clipping (mowing) once or twice may be necessary to provide light and give the seedling grasses and legumes a chance to compete. Grazing weeds is an alternative to clipping, if done when soils are firm enough. Realize that some weeds are not palatable or may be toxic, such as pigweed (Amaranthus spp.) and lambsquarters (Chenopodium album L.), which can accumulate high levels of nitrate, so avoid close grazing of fields with high weed pressure of these weeds. Light grazing can be followed by clipping to help control weeds that are not grazed.
Plan to control perennial weeds such as Canada thistle prior to establishment of pasture through use of crop rotation (where possible) or with appropriate herbicides in existing pastures to be renovated. Since most weed problems will be broad-leaved species, broadcast spraying with available pasture herbicides such as 2, 4-D, dicamba, or trichlopyr is recommended ONLY IF legumes are not present in the pasture, as these herbicides will also kill legumes. Spot treatment with appropriate herbicides may be used for problem areas where desirable legumes are present to minimize injury.
For more information on herbicide treatments, consult the pasture section of UWEX Bulletin A3646, Pest Management in Wisconsin Field Crops, available from your location UW Extension Office or can be viewed on the Internet at: http://learningstore.uwex.edu/pdf/A3646.pdf .
Haying or Grazing Management of New Pastures
Do not graze or cut pasture for hay until seedlings are well established, usually in the summer for a spring planting. If pasture was established the previous late summer/fall, delay use until the plants start stem elongation and flowering (late spring/early summer). Haying or grazing without allowing sufficient growth during establishment reduces plant vigor, increases weed problems and decreases stand longevity.
To minimize damage to pasture seedlings, graze through the area quickly with hungry animals and then remove them when they have stopped grazing. Avoid grazing when the soil surface is soft from recent rains to prevent damage from livestock hooves. Utilizing a rotational grazing system is recommended to aid in the development of new pasture plantings. With adequate rainfall and appropriate weather conditions, most new pastures can withstand two or three defoliations (clipping and/or grazing) in the establishment year.
Author: Rhonda R. Gildersleeve
Agriculture Agent- Iowa County UWEX
Originally Published: The Weekend Farmer, Spring 2007