Controlling Extreme Weeds After Extreme Events

Summary

​The aim of this Producer Demonstration Site (PDS) is to demonstrate to what extent improved weed control and follow-up management (eg: grazing, fertilizer or additional chemical control) improves both persistence and productivity of newly sown or degraded permanent pastures in fire affected areas. 

Objectives

By December 2025, in the Upper Murray and East Gippsland regions of Victoria the consultant and producer group will have:

1. 90% of core and 45% of observer group members more confident in identifying key pasture and weed species by;

   • Weed and pasture identification field day (late Autumn 2022)

   • Pasture assessment tools to estimate weed percentages and pasture composition

2. Assessment of appropriate interventions and control strategies

   • Autumn weed identification and control recommendations field day, and these recommendations implemented, on a host farm in each region (June 2022)

   • Development of long term weed control strategies for the 4 host farms.

3. Implement up to four different weed control strategies on newly sown pastures at demonstration host farms using a combination of approaches that include; chemicals, fertiliser and tactical rest periods, that result in a 20% higher desirable plant species by Spring 2025 (three years after sowing).

   • Undertake pasture benchmarking to establish priority weeds.

   • Implementation of individual weed control programs on host farms.

4. Implement two different weed control strategies on demonstration host farms, in consultation with lead agronomist, that result in a 10% improvement in desirable species in previously degraded but not resown pastures by Spring 2025.

5. Achieve a 50% increase in the number of observer producers of the two regions doing annual assessments of key weed species and a winter assessment of pasture composition across key paddocks by 2025.

6. 90% of core producers and 40% of observer produces indicate they have adopted or intend to adopt at least one of the weed control management practices implemented at one of the demonstration farms into their own property.

Progress

The project ‘Controlling Extreme Weeds After Extreme Events’ in the Upper Murray and Gippsland is implementing management strategies to increase pasture productivity post fires. 

Key strategies include; use of increased/capital fertilizer applications to address fertility deficiencies, use of fertilizer on previously unfertilized unimproved pastures, winter cleaning of broadleaf weeds, tactical use of grazing to manage spring residuals to promote tillering and use of extra knockdown chemical applications when sowing annual crops, to clean a paddock.  Use of fertiliser test strips has shown substantial responses to specific nutrients.

One site showed a 6% increase in pasture production in response to Phosphorus, and a 23% increase in response to molybdenum.  Upcoming activities include collection of autumn pasture data and an information session on ‘Identifying and managing soil constraints’.