Pasture Rejuvenation – Legumes and Herbs
Pasture rejuvenation with certain legume and herb species can reduce livestock methane emissions, while improving forage quality, feed efficiency, soil condition and fertility, and livestock reproductive rate. Target species contain plant secondary compounds including tannins, saponins, and other polyphenolic compounds that supress enteric methane production.
As an active area of research, the list of methane supressing species is still emerging as they evaluated across a range of Australian agro-ecological regions.
Currently, suitable temperate region species include Biserrula , Plantain, Chicory, Lucerne, Sulla, Sainfoin, and Lofus ; while subtropical species include Desmanthus and Luecaena .
Successful rejuvenation can depend on the existing soil condition and constraints present, appropriate species selection, seedbed preparation, and post sowing management. It is important to consider how pasture rejuvenation and species composition will influence forage quality, animal nutrition, welfare risks such as bloating, and how broader rotational management may need to adapt.
Success of pasture rejuvenation, and species suitability, is highly dependent on the regional context, and planning should be done in consultation with appropriate regional expertise.
Primary emissions benefit:
- Reduced livestock methane
Co-benefits:
- Improved forage quality and productivity
- Improved soil condition and fertility
- Animal welfare and reproductive rate
Potential barriers:
- Time and investment costs to establish new pasture
- Time in adapting grazing regimes and assessing livestock risks
- Establishing new pastures can be difficult
Considerations:
- Existing pasture quality and improvement achieved
- Appropriate species selection given soil x environment
- Establishment, production, and persistence behaviour
- Forage quality, nutritional profile and bloating risks
- Weed management
- Adaptation of rotational management
- Drought risks
Implementation
Successful rejuvenation of pasture requires a systematic approach that includes assessing the condition of the target landscape, selecting the right legume species, preparing the land, and developing a sowing and post-sowing management plan.
Development of a pasture rejuvenation FERP should consider the following implementation steps:
- Site assessment and planning: to understand the condition of the soil and any constraints, such as pH, nutrient imbalances, physical condition, and weed or pest issues to inform appropriate preparation and sowing plans.
- Selection of legume species: choose legume species suited to the local soil, climate, and grazing conditions. Seek local agronomic advice to ensure appropriate and resilient pasture composition, and to plan the timing of sowing, seeding rate, sowing method, and requirements for inoculation where appropriate.
- Preparation and sowing of land: based on site assessment and legume selection, land may require tillage, amelioration of soil constraints, and preparation of the seedbed.
- Post-sowing management: plan post-sowing management activities such as irrigation, weed control, and grazing management to ensure successful establishment.
- Continuous monitoring, evaluation, and learning: follow good practice management to evaluate pasture growth, pest and disease risks, appropriate nutrition. Consider periodic re-seeding where areas have failed to establish.
Activities:
- Legume seed purchase, including rhizobia inoculum where appropriate
- Fencing infrastructure
Monitoring:
- Proof of eligible purchases (invoices)
- Evidence of pasture rejuvenation activities (e.g. invoices, photographs)
- Enterprise emissions baseline reporting (initial and repeated at 2-year, and 5-year intervals)
Supporting services:
- Agronomic services and soil testing to assess and/or prepare site
- Agronomic services to select and establish effective legume cover
Stacking compatibility:
- Variable Rate (VR) lime
- Variable Rate (VR) fertiliser
- Nitrification inhibitors (with attention to required withholding periods)
- Solar energy and storage (e.g. on-ground photovoltaics)
- Permanent planting (e.g. as wind breaks)
The magnitude of benefit depends on enterprise size and composition, pasture condition, soil variability, and rotational management practices.