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pasture grasses

Objective of the Lecture

  • Description of Common Pasture Grasses: Focus on sown species in New Zealand.
  • Identification: Understanding how to recognize pasture grass plants.
  • Management: Importance of understanding adaptation to climatic and soil factors.

Key Factors in Pasture Grass Management

  • Climatic Factors: Mainly temperature and moisture.
  • Edaphic Factors: Soil fertility and grazing management.
    • Grazing Tolerance: Ability to withstand grazing pressures.
    • Insect Pest Tolerance: Influence on grass plants' persistence.
  • Yield and Nutritional Value:
    • Annual Dry Matter Yields: Amount of dry matter produced.
    • Nutritional Characteristics:
    • Metabolizable Energy (ME) value
    • Crude protein content
    • Fiber content
    • Digestibility

Identifying Grass Species

  • Importance of Identification: Helps in understanding grass adaptability and management suitability.
  • Field Work: Engaging in hands-on identification of grass tillers.
  • Resources: Massey University's Pasture Plant Identification website.
  • Interactive Learning: "Grasp View" software by the University of Nottingham for enhanced understanding of grass morphology.

Main Grass Species in New Zealand

Ryegrass Overview

  • Key Types of Ryegrass:
    • Perennial Ryegrass (Lolium perenne): Most commonly sown; persistent for several years.
    • Annual Ryegrass (Lolium multiflorum): Used for short periods; performs well during one season.
    • Hybrid Ryegrass: Cross between perennial and annual; includes short rotation and long rotation types.
    • Italian Ryegrass: May persist for one or two seasons, suitable for various growing cycles.

Perennial Ryegrass

  • Properties:
    • Growth: Emerald green color, shiny leaves with a folded base, sometimes with a purple hue.
    • Soil Fertility: Requires medium to high fertility, optimal Olsen P values around 20-25.
    • Drought Tolerance: Moderate; may struggle in extreme dry conditions.
    • Establishment: Economically viable with various available cultivars.
  • Endophytes: Fungi inside the grass important for pest deterrence and overall health.

Cultivar Differences in Ryegrass

  • RAGT NZ: Key seed company producing various ryegrass cultivars with distinguishing features.
  • Novel Endophytes: Enhancements in pest deterrence and resistance.
  • Ploidy Variation: Differences in diploid and tetraploid cultivars affecting growth and persistence.
    • Early flowering (mid to late October) impacts pasture growth profiles.

Alternative Grass Species

  • Tall Fescue (Lolium arundinaceum):

    • Characteristics: Tolerant of wet and dry conditions; requires high fertility.
    • Management: More sensitive to grazing; slower establishment.
    • Endophytes: Cultivars available with novel endophytes for pest deterrent effects.

  • Cocksfoot (Dactylis glomerata):

    • Characteristics: Persistent in droughts, suited to medium fertility soils.
    • Grazing Conditions: Performs well in both lax and frequent grazing scenarios.

  • Brome Species:

    • Includes Grazing Brome (Bromus stamineus), Pasture Brome (Bromus valdivianus), and Prairie Grass (Bromus wildei).
    • Differences: Variability in grazing tolerance and drought resilience.

  • Timothy (Phleum pratense):

    • Characteristics: Suitable for summer moisture; high-quality but slow to establish.

  • Phalaris (Phalaris aquatica):

    • Properties: Good drought tolerance but can cause health issues in livestock.

Conclusion

  • Perennial Ryegrass: Dominant grass species, inexpensive to establish, suitable for various environments in New Zealand.
  • Cocksfoot and Alternatives: Viable options when ryegrass fails; each alternative has unique requirements and benefits.

Resources for Further Study

  • Textbook References:

    • "New Zealand Pasture and Crop Science"
    • "Pasture and Forage Plants for New Zealand"

  • Online Resources:

    • National Forage Variety Trials (www.pbra.co.nz) for comparative yield data.