Testing Tropicals - NSW Southern Slopes

Summary

The Southern slopes of NSW has a winter dominant rainfall pattern but with a changing climate, is now experiencing increasing summer rainfall. Pasture species within this region are dominated by winter dominant perennials or annuals. Few perennial species are currently capable of utilizing summer rainfall with the exception to some summer active perennials (e.g., Cocksfoot or Phalaris which do not produce significant amounts of feed and compromise persistence) and lucerne (which is greatly constrained by soil factors).  ​

This producer demonstration site (PDS) aims to demonstrate tropical and sub-tropical pasture species in production systems of the southern slopes of NSW and what management adaptations need to be made to successfully incorporate these species into southern grazing systems. 

Objectives

By December 2026, in the south-west slopes of NSW:

1. Three or more tropical/subtropical pastures will be sown in commercial size paddocks on three different properties. These will demonstrate/assess the potential of these species to:

   • establish and persist in southern NSW farm systems

   • increase groundcover

   • produce summer feed in seasons of variable summer rainfall (fill summer feed gap)

   • impact on liveweight gain within farm systems

   • contribute to the farm system

2. Increase the knowledge and skills of 80% core producers and 60% of observer producers with respect to:

   • perennial pasture options for filling the summer feed gap

   • pre-sowing paddock preparation

   • pasture establishment

   • companion species selection

   • pasture management (including grazing management) in summer-active pastures

3. Conduct a cost benefit analysis to determine the economic impact of sowing summer pasture varieties within a farm system.

4. Build a publicly available resource area on the HLN website with information about the key learnings emerging from the trials (see objectives 1 & 2 above). Target website hits: 500

5. Conduct an annual farm tour of PDS sites to showcase outcomes and provide producers with an opportunity to interact with Tropical/summer-active pastures experts. Target number of producers on field tours: 100

6. Record farmer video blogs of the pastures at key stages in their management which will be published on social media and/or the HLN website to enable greater producer engagement. Target website and social media hits: 1000

Progress

HLN is two years into the ‘Testing Tropicals in the NSW Southern Slopes MLA PDS’ https://holbrooklandcare.org.au/projects/testing-tropicals-2/.  

So far, 3 producer demonstration sites have been established at Henty, Yerong Creek & Pulletop NSW.   Wetter than average seasons in 2022 and 2023 saw established sub-tropical pastures perform well, demonstrating the production potential of these species (standout species Premier digit) in southern grazing systems.   

Over the winter of 2023, the core producer group trialled applying Gibberellic Acid and Urea to a still active sub-tropical pasture in an attempt to increase winter production. Unsurprisingly, no treatments increased the production of sub-tropical species but did increase the production of temperate species and the impact of these treatments on sub-tropical grass persistence will be monitored over the coming years.  Over-sowing sub-tropical pastures with a desirable species (e.g. clover and annual ryegrass) to boost production, replace annual grass weeds and limit competition for soil moisture in summer is also being tested.   

Discussions amongst core producers have highlighted the growing role of sub-tropical species (mainly Premier Digit) in complementing (not replacing) temperate species in southern grazing systems. Whilst not producing the same livestock growth rates as lucerne, sub-tropicals had performed well on ‘secondary’ country (i.e. lighter soils and hill country) where temperate species struggled. So far, this is where these species appear to have most value utilizing summer rainfall, providing non-bloat green feed production and providing competition for summer weeds. With a predicted El Nino, we are looking forward to seeing how these species perform in the drier years.