B.PAS.0507 - Management options and species evaluation to increase productivity in dieback affected pastures

Summary

This project forms part of MLA's Pasture Dieback (PD) response under the federal government grant. The aim of this project was to develop and evaluate alternative agronomic practices for pasture management and feed options for livestock in PD affected areas. Trial sites leveraged against others forming part of a network of collaborative demonstration sites to communicate effective practices to producers.

Objectives

Objectives of the project included to identify and evaluate:

• Economically viable pasture management options that could increase pasture productivity and produce feed for stock in PD affected Queensland grazing regions.
• Pasture species or varieties that are tolerant to PD and/or mealybugs with required agronomic traits to be productive and economically viable in Queensland’s grazing regions.
• Communication of results and recommendations to producers via field days, factsheets, and other communication methods.

Key findings

Assessment of previous MLA field trial sites indicated that treatments using cultivation and resowing with a grass and/or grass and legume mix generally gave the best results in useful plant coverage. Cultivating and allowing for natural regeneration resulted in a higher weed incidence, and more dieback expression.

Benefits to industry

Practical strategies for producers including:

• Confirmation that legumes are not susceptible to PD.
• Cultivation (or stick raking), then re-seeding with a legume or pasture plus legume mix, and fertilising with 150 kg/ha DAP, has provided the best productivity (so far) on dieback affected pastures.
• Urea fertiliser is not helpful. Apply products that include phosphate such as MAP or DAP and use soil test results to guide fertiliser mix and application rates.
• Burning, or cultivating without re-seeding, are likely to have only short-term benefits and can increase dieback and/or weed growth.
• Simple strategies, such as stick raking, can be used for removing the bulk of dieback affected plants followed by resowing areas with improved grasses and legumes.

MLA action

Phase I of the project established field trials to test cost effective management strategies and species resistance to dieback. MLA contracted Phase II of this work to monitor species performance and impact of management over three seasons (B.PAS.0513).

Future research

Grass and legume mixes appear to be giving good coverage in PD sites, and variety trials have had varying degrees of germination. Longer term studies to assess the impact of PD on these treatments/varieties are required.