Common Legumes on the Central Tablelands

Clare Edwards, Senior Lands Services Officer – Pastures based in Mudgee

A diverse range of pasture legumes are adapted to the Central Tablelands Local Land Services area. These legumes include native, naturalised and introduced species. Many are regarded as an asset, potentially improving forage quality and quantity and ultimately, animal performance. Pasture legumes are also capable of boosting soil fertility through nitrogen fixation. Legumes are also recognized as an important component of pasture diversity.

This article covers some of the most common pasture legumes found in the area. I have also added a couple of 'newish' legumes that are currently being researched for their potential.

Native legumes

Native legumes include the most common perennial species of Glycine and Desmodium. They are warm season growing, twining plants often found in woodlands and native grass dominated pastures – particularly paddocks that have been rotationally grazed or conservatively stocked. I have seen some beautiful examples of these in Capertee Valley recently. There is little research on the value of these legumes play agricultural systems and what encourages them to persist and perform. However, they are an important element in the diversity of pastures.

Naturalised legumes

These legumes were introduced to the region as either a deliberate planting or by accident. They now grow and spread naturally without the need for sowing. A number of these can be of significant value to pastures and animal production. They are often found across a range of soil types, fertility levels and variable landscapes with disturbance such as the road verges. The majority are cool season hard-seeded annuals. They are often seasonally sporadic in their appearance, with some years having dense populations. The main groups are the Medics (Medicago spp.) such as Spiny Burr Medic and the Clovers (Trifolium spp.) for example Haresfoot, Hop or Yellow Clover. The medics tend to grow on the heavier soils with the clovers often on the lighter lower pH soils. There are also a number of introduced legumes both annuals and perennials (such as Lucerne, Woolly pod vetch and White clover) that are commonly sown and become naturalised on the roadsides, table drains and along creeks and rivers.

Last year, we took a number of pasture quality samples from a few of these naturalised legumes. These results are not replicated, but highlight an area of possible research on how they play an important part of adding nitrogen and quality feed for the livestock industries.

Table 1 Forage values of some naturalised legumes 2014. These were grab samples not replicated or repeated. Results from: NSW DPI, Feed Quality Service, Wagga Wagga Agricultural Institute.
* = results from NW Slopes NSW Rowling and Edwards (2009).

Introduced legumes

There are a number of sown introduced legumes that are used on the tablelands. These introduced legumes often have superior features such as high quality feed, higher production, higher quality for animal production and potential response to applied fertiliser. Some species such as Lucerne are important perennials and can be used during the pasture phases of cropping and can produce high quality hay and silage. The annual Subterranean clover is the most common annual in the area in both native and improved pastures. It is well adapted to many of the Central Tablelands soils. White clover, a perennial, is often used in the high rainfall and high elevation areas in permanent pasture situations. I have also seen Strawberry clover being used in saline and waterlogged areas. There is also a little bit of Red clover in the area but not as much as I thought there would be.

There are a number of hard seeded legumes which are currently been looked at for the Central Tablelands. These include Arrowleaf clover, Biserrula, French and Yellow Serradella, Gland and Bladder clover. Some, for example Balansa, have been around for a while. I had Serradella in trials 18 years ago. We have had mixed results from these species in demonstration trials.

Why hard seededness? And why should we investigate this trait?

Hard seededness is a seed dormancy mechanism. It is an important trait that allows the plant to create a long term seed bank. It can regulate the germination of the plant and so protect against false breaks. As an annual, this is important; some years we have good soil moisture and cool conditions early on, only to receive a couple of hot, dry weeks at the end of summer or in early autumn. Newly germinated plants find it hard to survive in these conditions. Hard seededness also prevents every single seed germinating at the same time. This can lead to crowding and competition for nutrients, space, light and moisture. Lastly, the hard seeded trait increases the future survival of the plant. Often only a percentage of seed germinates in any one year and there is seed still remaining in the soil. We saw this last year (2014) in March – April, when conditions where right and there was minimal competition with other plant species at germination. A lot of landholders commented on the amount of sub clover in their pasture, even though there had been little sub clover in the last few years and they had not sown any seed for several years.

Many annuals have a percentage of hard seededness. There can also be differences between varieties for example the sub clover varieties of Woogenellup can have lower level of hard seededness when compared to the variety of Seaton Park LF. It is often commented that landholders see a disappointing second year of hard seeded legumes, partly due to pasture management in the establishment year.

Further Information  

If you would like further information on the trials and demonstrations, the species we used or legumes in general, please do not hesitate to call myself or Phil Cranney.

There is also a good NSW DPI publication on the web worth looking at "Naturalised pasture legumes" NSW DPI Primefact 651