Establishing Pastures: Selecting a Seed Mixture

Table of Contents

1. Growing Conditions
2. Purpose of the Mixture
3. Composition of the Mixture
4. Other Pasture Establishment Recommendations
   • Soil Test
   • Types of Mixtures
   • Seeding Rates
   • Legume Inoculation
   • The Seedbed
   • Seeding Technique
   • Weed Control When Seeding Forage Stands
5. Related Links

Growing Conditions

Select a seed mixture that is adapted to the growing con-ditions in the field. Consider drainage, soil pH, natural fertility, soil depth and texture. Table 2-1, Soil Drainage Requirements of Forage Species, shows the tolerances of the major forage species to drainage conditions. This is the most important factor to consider because it is the most difficult or expensive factor to change.

Figure 3-1, Soil Drainage Requirements of Forage Species

Table 2-2, pH Range for Forage Species, shows the pH range for good growth of different species.

Table 2-2. pH Range for Forage Species
Text Equivalent of Image

Consider how "early" the area to be seeded is in most years.

• Orchardgrass, meadow foxtail or meadow bromegrass are ideal for fields that dry quickly and are accessible early in the pasture season. These fast-starting grasses can advance the normal grazing season, but the first 2 become unpalatable and of poor feed quality if allowed to mature. Once ready to be grazed the animals must have access to them.
• Reed canarygrass-based mixtures are also ideal for early land.
• A trefoil-based mixture with a grass such as tall fescue, bromegrass or timothy is suitable for fields that are slow to dry.

Purpose of the Mixture

The species in the mixture and the proportion of each species depends on the use of the mixture: hay-pasture, permanent pasture, or exercise area. Species such as bromegrass, timothy, orchardgrass, tall fescue, reed canarygrass, alfalfa, and trefoil provide good hay yields as well as pasture. Shorter growing species, such as the bluegrasses, creeping red fescue, redtop and white clover, are not suitable for hay but are useful in pastures or exercise paddocks.

Composition of the Mixture

Legume-grass mixtures are preferred for seeding pastures because:

• they produce higher animal gains and milk production
• do not require nitrogen fertilizer to yield well, and
• perform better than grass pastures during hot, dry weather.

The legume component in the mixture improves the nutritional value of the pasture. The feed quality of legumes is superior to that of grasses and does not decline as rapidly with age. As well, grasses grown with legumes usually contain a higher percentage of crude protein than grasses grown in pure stands. The stimulating affect on the grass is caused by the release of nitrogen compounds from legume roots and root nodules. Bacteria living symbiotically in the root nodules use nitrogen from the air for their growth and development. While most of the "fixed" nitrogen is available to the legume, some is excreted into the soil, becoming available to grasses. When bacteria dies and nodules decompose, additional nitrogen becomes available to the grasses.

Ladino and intermediate white clovers supply relatively high amounts of nitrogen (around 200 kg/ha) to companion grasses, while alfalfa, birdsfoot trefoil and red clover supply smaller amounts (usually 80-140 kg/ha). Nitrogen fixation allows legume-grass mixtures to yield well without adding nitrogen fertilizer. Phosphorus and potassium plant nutrition levels in the soil must be maintained to ensure balanced growth of the legume and grass components.

Legumes generally have deeper root systems than grasses. This allows access to deeper soil moisture and in turn, legumes yield better in the summer. This produces a more steady production of forage over the grazing season. Overgrazing, which damages root systems, destroys this advantage of having a good legume population in a pasture.

Grasses grown with legumes:

• reduce the danger of bloat
• increase the possibility of having a thick pasture without weeds
• help to reduce winterkill of legumes. If legumes winterkill, the grasses can be fertilized with nitrogen to provide pasture for the season.

Legume-grass mixtures succeed because of their natural, close association due to differences in nutritive requirements and root systems. Complementary grasses and legumes make the best use of climatic, soil and growing conditions.

Related Links

... on forages and pastures, visit Forages and Pastures (OMAFRA)
... on weed control, order Publication 75 Guide to Weed Control: Forage Crops
... on agronomy for field crops, order Pub. 811 Agronomy Guide for Field Crops: Chapter 3 Forages
... on field crop protection, order Publication 812, Field Crop Protection Guide
... on livestock, visit Livestock (OMAFRA)