Serradella produces its maximum yield at lower soil test phosphorus levels than most other winter legume species. This attribute can potentially save Australian livestock producers many millions of dollars per annum in fertiliser costs provided they can successfully grow serradella pastures in their farming district.
This is one part of a major study to improve the effectiveness of phosphorus fertiliser use in pastures that is funded by the Australian Government’s Department of Agriculture and Water Resources Rural R and D for Profit program. Funding bodies part of the research also include MLA, Dairy Australia, AWI and farmer groups. CSIRO and NSW Department of Primary Industries led the study, but also involves Universities in Western Australia and farmer groups in northern and southern NSW, Victoria and southern WA.
In districts where serradella is already grown, the research, now well under way, is assessing phosphorus soil test values needed for maximum yields. In districts where serradella is not commonly grown, the research is focussed on testing the persistence of serradella in mixed pastures.
Research includes examining legume variety flowering time across a range of Australian environments. Preliminary results are providing a better understanding of flowering time among the serradella cultivars. In contrast to early varieties suited to drier areas, for example, mid-to-late season types like Avila are showing promise for higher rainfall and non-traditional serradella areas.
The research is also identifying hard seededness and seed softening patterns in serradella varieties as these features are essential for legume persistence and will underpin the use of this extremely valuable species across more diverse environments.
While it is still early days, Dr Richard Simpson, CSIRO Agriculture and Food research agronomist, reports good progress with already important findings. The potential to extend the area where serradella can be successfully grown and to utilise its greater soil phosphorus efficiency is particularly exciting, he believes.
Researchers in this project (for example Dr Suzanne Boshma DPI Tamworth and Richard Hayes at Goulburn) already see advantages in being able to use serradella more reliably in non-traditional serradella areas. They are confident that expanding the species use is more likely given the new knowledge generated by the research.
Serradella grows persistently and productively across most of our central west NSW farm with some well appreciated features. This includes largely non-bloating, very important in flush years like 2016 when bloat caused enormous losses on many properties dependent on high risk species.
Some years we see many annual legumes decimated in spring by high aphid explosions. We have commonly noted serradella, especially yellow varieties, have good tolerance. Other strong features include deeper rooting (and faster than sub clover) and better acid soil tolerance than sub clover.
Richard Simpson is always cautious in not “getting ahead of ourselves” when undertaking major research projects like this one.
But previous research has shown in field and glasshouse studies, that some plant species (particularly the serradellas) and varieties within a species can vary enormously in their efficiency in capturing soil phosphorus. This can potentially reduce the phosphorus soil test levels at which these pasture species need to be grown.
The current study aims to confirm that serradella can be fully productive at much lower soil phosphorus levels than species like sub clover under typical management conditions. And to open up the use of the species in non-traditional; serradella areas.
