In-Depth Notes on Pasture Legumes and Herbs in New Zealand

Overview of Pasture Legumes and Herbs

• Objective: Discuss common pasture legumes and herbs in New Zealand, focusing on sown species, their identification, morphology, growth behavior, climatic and edaphic adaptations.
• Climatic Factors: Temperature and moisture response.
• Edaphic Factors: Soil fertility, grazing management, pest tolerance.
• Yield Considerations: Acknowledge annual yield potential and seasonal yield patterns; consider nutritional values like metabolizable energy, crude protein, and fiber content.

Identification and Growth Forms

• Identifying legume pastures is essential for understanding environmental suitability and management decisions.
• Useful resource: Massey University Pasture Plant Identification Website.

White Clover (Trifolium repens)

• Overview: Most common perennial legume in New Zealand; suited for maritime temperate conditions.

  • Growth Form: Stolons allow for spreading and reproduction;
  • Reproduces via viable seed and vegetative means.

• Nitrogen Fixation:

  • Fixes approximately 2 kg of nitrogen per 100 kg of dry matter produced;
  • Annual fixation can range from 30 to 50 kg N/ha depending on clover presence in ryegrass pastures.

• Nutritional Value:

  • Higher feed quality relative to grasses;
  • ME value of (12-13) MJ/kg dry matter vs. ryegrass 10-11 MJ/kg.
  • Crude protein content: (30-35)\% of dry matter vs. ryegrass's (20-25)\%.

• Pest Management: Vulnerable to clover root weevil introduced in the 90s, affecting persistence but populations have stabilized.

• Cultivar Considerations: Cultivars vary by leaf size and stolon density, impacting grazing tolerance and growth characteristics.

  • Large leaf cultivars (e.g., Kopu) have lower stolon density;
  • Smaller leaf cultivars (e.g., Demand) compensate with higher stolon density.

• Seasonal Growth Profile: Resilient growth in late spring and summer enhances pasture growth when moisture is abundant.

Red Clover (Trifolium pratense)

• Overview: Perennial, short-lived legume; upright growth form.
• Nitrogen Fixation: Similar ability to form symbiotic relationships with rhizobia for nitrogen uptake.
• Nutritional Aspects: Higher protein content but can disrupt reproductive cycles in sheep due to estrogenic compounds.
• Cultivar Management: Varying cultivars differ in flowering time, grazing tolerance, and persistence based on ploidy level (diploid vs. tetraploid).

Subterranean Clover (Trifolium subterraneum)

• Characteristics: True annual legume; survives drought via early reproduction and seed production.
• Sowing Recommendations: Typically sown in autumn for rapid establishment during the warmer months.
• Seed Size: Larger seed compared to white and red clovers.

Lucerne (Medicago sativa)

• Overview: Deep-rooted perennial legume; suited for dry, well-drained soils.
• Nutritional Value: ME value around 11-13 MJ/kg, crude protein about 35\% dry matter.
• Management: Requires careful rotational grazing to respread energy for regrowth.
• Cultivar Variability: Multiple cultivars exist, each offering unique advantages in different conditions.

Herbs in Pasture Systems

Chicory (Cichorium intybus)

• Characteristics: Short-lived perennial with taproots and drought tolerance.
• Nutritional Profile: High-quality feed and potential anthelmintic properties.
• Utilization: Grown as short-term forage or in mixes with clovers.

Narrow Leaf Plantain (Plantago lanceolata)

• Characteristics: Leafy perennial with fibrous root structure; drought resistant.
• Nutritional Considerations: High mineral content; evidence suggests it may reduce nitrate levels in livestock urine.

Key Takeaways on Pasture Management

• Predominantly using ryegrass and white clover but evaluating alternatives is essential.
• Understanding specific cultivar traits helps in making informed decisions suitable for environmental and livestock needs.
• Reference materials include the New Zealand Pasture and Crop Science textbooks and Pasture and Forage Plants in New Zealand for more detailed information on legumes and herbs.