L.PDS.1803 - EPDS - Annual grass control strategies in a perennial pasture system
The incursion of annual weeds into pastures and a reduced number of herbicide options for their control prompted Perennial Pasture Systems (PPS) to look for a broader range of management techniques.
| Project start date: | 30 April 2018 |
| Project end date: | 16 June 2023 |
| Publication date: | 01 May 2024 |
| Project status: | Completed |
| Livestock species: | Grass-fed Cattle, Sheep, Lamb |
| Relevant regions: | Victoria |
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Summary
The incursion of annual weeds into pastures and a reduced number of herbicide options for their control prompted Perennial Pasture Systems (PPS) to look for a broader range of management techniques. The main PPS group is based around Stawell and Ararat with rainfall totals of 450-500mm per annum. Members predominantly run perennial pasture-based systems with sheep; both prime lamb and wool enterprises.
This demonstration began with a focus on annual grass weeds generally, however early in the project there was a shift in focus to barley grass control. Barley grass (Hordeum leporinum) continues to be an issue in pastures, especially after periods of dry conditions and where perennial pasture has thinned.
Barley grass can have a huge impact on the ability of growers to turn off seed-free meat and wool, with producers incurring price downgrades to various extents. In addition to the price downgrades there are significant animal health issues that arise from the sharp seeds. The invasion of annual grasses also has a deleterious effect on desirable grasses; competing for light, nutrients and moisture. The aim of the project was to reduce the reliance on chemical control by investigating other options such as mechanical removal, increased competition and grazing management. PPS aimed to demonstrate single or combined methods of reducing barley grass in perennial pasture on member farms.
Objectives
To demonstrate the impact (both positive and negative) of various barley grass control strategies on total dry matter production and pasture composition in perennial pastures. To demonstrate a combination of options to reduce barley grass seed numbers across member sites. To increase the knowledge and skills of the producers regarding barley grass control in perennial pastures.
Key findings
The seven strategies measured varying levels of success. Mechanical removal and increasing competition in combination with chemical control was the most successful at reducing barley grass during the project. Other successes were the mechanical removal with methods such as silage, which also make the ensiled seed unviable. A reduction from competition alone was difficult to achieve in demonstration and intense grazing management was problematic to manage with neither achieving a reduction in barley grass. Chemicals showed a success in reducing barley grass, however the effects were not long lived, often a second germination is possible if conditions are favourable.
The Mount Dryden Site 2 result included a cost-benefit analysis. This showed a benefit where chemical control and nitrogen plus over-sowing were trialled of $842/ha above areas where weed control and Nitrogen were used without over sowing. A reduction in barley grass numbers was also achieved, which remained in the two seasons following treatment.
The silage made at sites during the demonstration was also tested for seed viability, which returned results indicating that 0% of the ensiled barley grass seeds tested were viable. This result combined with an overall reduction in barley grass numbers after the silage are considerable for farmers in the area that can use this management technique.
The effects of COVID-19 on the demonstration resulted in a reduced number of face-to-face events being held, however written publications from the demonstration have been spread widely throughout the area. The project overview was also delivered to the 61st Grasslands Conference in 2020.
An increase in knowledge and skills was recorded from participants surveyed.
Benefits to industry
This project has increased the overall knowledge of barley grass across core and associate members. This includes extension of practical management techniques to reduce the risk of animal welfare issues and price downgrades of sheep meat and wool due to barley grass seeds.
Results gained in this project show a reduction in barley grass seed set in one year can continue to benefit pastures for up to two years after the initial action was taken, which could reduce the reliance on chemical control for some members.
MLA action
MLA continues to deliver the Producer Demonstration Site (PDS) program, supporting livestock producers working in peer-to-peer groups to pursue new skills, knowledge and management practices applicable to their own commercial livestock production systems.
Future research
• Further quantification of feed quality results in a changing climate and with improved cultivars.
• Further investigation into late season barley grass management methods such as slashing and mulching to manage impacts on animals.
More information
| Project manager: | Alana McEwan |
| Contact email: | reports@mla.com.au |
| Primary researcher: | Department of Energy Env & Climate |
