Sod Seeding Alfalfa

Direct seeding alfalfa into existing sod offers a practical alternative to conventional pasture renovation. While traditional methods rely on multiple tillage passes, they are costly, time-consuming, and expose land to erosion. Sod seeding conserves soil moisture, reduces erosion risk, and minimizes equipment wear. However, establishment success depends on proper sod suppression and fertility management.
 
Limitations of Conventional Renovation
  • High cost and labour requirements.
  • Grazing restrictions during renovation.
  • Unsuitable for stony, saline, or rugged terrain.
  • Increased erosion risk and soil moisture loss.
  • No guarantee of successful establishment.
 
Advantages of Direct Seeding
  • Lower cost and fewer passes.
  • Conserves soil moisture.
  • Reduces erosion risk.
  • Easier access to rough terrain.
  • Minimizes delays due to weather.
 
Sod seeding alfalfa into native hay stands can significantly enhance forage yield and quality, especially in areas unsuitable for conventional tillage due to stony or saline soils.
Year
Sod Seeded (lb/ac)
Native Hay (lb/ac)
Seed-down
522
432
2nd Year
1,654
480
3rd Year
3,760
600
4th Year
4,940
625
Protein content also improves dramatically—from 7–8% in native hay to 13–14% in sod-seeded alfalfa.
Modern sod-seeding drills and zero-till practices make this approach practical, offering benefits such as fuel savings and soil conservation.
 
Steps to Improved Survival
Plan one year ahead to control weeds and reduce competition. It is imperative to control weeds and native grass growth long enough to allow for seedling establishment and reduce trash cover for easy drill penetration. Techniques include:
  • Clipping or overgrazing
  • Burning
  • Herbicide application (e.g., Roundup or Gramoxone)
1.      Suppression
a.      Apply Glyphosate (Roundup) at 1 L/ac (2.5 L/ha) before seeding when sod is actively growing.
b.      Gramoxone: 1.25–2.2 L/ac for temporary suppression; allows seedling establishment, apply in May when grasses are 2-4 inches tall.
c.      2,4-D: - for broadleaf control but herbicide residues may inhibit seedling establishment
2.      Seed Quality
Use registered forage seed and inoculate with rhizobia.
3.      Proper Equipment
Utilize zero-till or forage drills for good seed-to-soil contact.
4.      Fertility Management
Soil test and apply phosphorus at seeding (26.7–35.6 lb/ac or 30–40 kg/ha P₂O₅) and avoid nitrogen to reduce grass competition
5.      Species Selection
·          Alfalfa: 7–10 lb/ac; vigorous, adaptable, suitable for hay and pasture.
·          Birdsfoot Trefoil: 2 lb/ac; non-bloating, moisture tolerant.
·          Sweet Clover: 8 lb/ac; drought and salt tolerant but biennial.
6.     Seeding Guidelines
·          Best in early spring or as dormant seeding after Nov. 1.
·          Ideal depth: ~0.39 in on firm, moist seedbed.
·          Inoculate legumes with appropriate rhizobium.
7.  Stand Management
·          Avoid close grazing of seedlings.
·          Maintain fertility and control weeds.
·          Do not graze or harvest between Aug. 15 and first frost.
·          Leave a minimum of 3-4 inches of residual before going into winter if grazing
·          Established stands: rotational grazing (up to 6 days) followed by 24–30 days rest.
 
Key Findings from University of Manitoba Study
  • Sod suppression is critical: Burnoff more than doubled alfalfa dry matter production compared to untreated sod.
  • Phosphorus improves establishment: 30 kg/ha P₂O₅ significantly increased emergence and vigour; higher rates showed no additional benefit.
  • Moisture matters: Suppression allows seedlings to utilize available moisture effectively.
Dry Matter Production (kg/ha)
Gladstone Site
  • Sprayed + 30 kg/ha P₂O₅: 4,330 → 5,836
  • Not Sprayed + 30 kg/ha P₂O₅: 776 → 336
Portage Site
  • Sprayed + 30 kg/ha P₂O₅: 5,758 → 7,732
  • Not Sprayed + 30 kg/ha P₂O₅: 2,563 → 2,745
 
Things to Remember
  • Remove sod competition for better emergence and survival.
  • Fertilize based on soil test recommendations.
  • Manage soil moisture carefully, critical on dry sites.
  • Follow best practices for grazing and stand management after establishment.