With favourable market and weather conditions comes the opportunity to invest in future feedbase options to bolster your business.
In the right environment and production system, the incorporation of legumes, either as standalone pasture or in mixes, can significantly boost productivity whilst providing drought resilience and environmental benefits.
Legumes commonly grown in southern Australia include sub-clovers, medics and Lucerne. Research has shown the benefits of hard-seeded annual legumes such as Arrowleaf Clover, Biserrula, Bladder Clover, Gland Clover, Vetch and Serradella as a valuable addition to the feedbase and a resilient substitute for sub-clovers and medics.
Common legumes grown in the north include Cowpeas, Lablab, Lucerne Stylos and Burgundy Bean, whilst perennials like Leucaena and Desmanthus are becoming a popular source of feed due to their year-round reliability, feed quality and drought tolerance.
Here are five ways that legumes could benefit your business:
- More feed, less fertiliser
Legumes form a symbiotic relationship with Rhizobium bacteria, which enable plants to fix nitrogen (N) from the atmosphere through their root system and make it available to other pasture species.
This provides (free!) soil-nitrogen to non-legume plants (grasses and crops), reducing the reliance on applied nitrogen fertiliser and bringing down the associated costs and labour of fertiliser application. Having adequate nitrogen available to plants in the soil is also essential for an optimal response to applied phosphorus (P) and sulphur (S).
The nitrogen fixed by legumes boosts the performance of pasture grasses to produce higher quality and quantity of dry matter, providing a nutritious source of feed for livestock. For best pasture growth, key nutrients need to be present at the required levels and soil testing can inform fertiliser decisions. Legumes can also help to fill seasonal feed gaps and extend the pasture life.
- Faster weight gains and healthier animals
Legume pastures provide palatable, digestible, high protein feed for livestock. Feed intake of legumes in ruminants can be higher than grasses due to the rapid breakdown of legume material.
Legumes in the pasture can extend the period of high-quality green feed when feed quality from grasses is in decline or low, giving producers a more reliable and flexible feed for meeting market specifications year-round.
They can also contain beneficial compounds that reduce bloat risk. Both serradellas and Arrow Leaf Clover contain condensed tannins that reduce the risk of bloat; an important factor when looking at pasture species for bloat resistance is the level of condensed tannins.
- A more resilient feedbase
Incorporation of hard-seeded and woody legumes in pasture commonly reduces production risks and bolsters resilience to climatic conditions and seasonal variations. Some perennial legumes can persist for decades with good management. They also respond quickly following drought-breaking rainfall. This is due to their deeper root systems and capacity to produce sufficient seed for regeneration, even under adverse growing conditions.
The additional ground cover provided by legumes in these circumstances helps to reduce risks of runoff and erosion, and can be helpful in reducing weed burden.
- An ally against dieback
Annual and perennial forage legume species are not affected by dieback, nor are they hosts to mealybug. Incorporating tolerant pasture species such as legumes and tolerant grasses or other forages, should be key practices to consider in addressing dieback.
Recent trials showed that cultivating, adding moderate rates of nitrogen and phosphorus fertiliser and then re-sowing dieback-affected areas with legumes (e.g. Butterfly Pea, Lablab, Desmanthus) reliably improved plant biomass. Re-sowing with a mix of legume and pasture grass species was also frequently beneficial, in that it increased feed available for cattle.
- Towards carbon neutral 2030 (CN30)
When it comes to carbon, legumes can offer multiple benefits, including carbon capture and storage as well as emissions reductions.
Legumes help to build soil carbon by improving soil health and promoting root growth. Some of the woody plants help to lock up carbon in stems and root matter.
They can also contain different levels of useful compounds such as condensed tannins that assist animal production and have potential to reduce livestock methane emissions. Specifically, research has shown in the northern Australian context that Leucaena and Desmanthus look promising in reducing enteric methane production.
Like any plant, legumes will perform best in the right environment and the right production system. Legumes must be inoculated with the correct strain of Rhizobia bacteria to grow well, and managed for the conditions.
