Annual grass control strategies in perennial pastures

Summary

The Enhanced Producer Demonstration Site (EPDS) concept was developed in 2014 as a partnership between Meat & Livestock Australia (MLA) and Agriculture Victoria. The partnership brings the benefits of integrating with Agriculture Victoria’s  BestWool/BestLamb and BetterBeef network of producers and groups receive assistance from Agriculture Victoria extension staff throughout the demonstrations including monitoring, evaluation, reporting and communication.

This project comprised of two parts. Firstly, the completion of a suite of eight (Phase 1) demonstrations that commenced in 2014, and secondly, a further seven (Phase 2) demonstrations, established through an expression of interest (EOI) process that commenced in 2018 / 19. 

Demonstrating the impact of various barley grass control strategies on total dry matter production and pasture composition in perennial pastures.

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 grassseed 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.

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.