L.LSM.0018 - No more gaps with superior shrub systems

Summary

Nutritional gaps present the largest production cost to grassfed meat and wool producers across Mediterranean and dry areas of Australia. Gaps lead to suboptimal ruminant production and conservative whole-farm stocking rates. A recent modelling study found that average stocking rates in the WA wheatbelt may be about 40% lower than the calculated optimum, although the top 25% most profitable producers are close to optimally stocked (Young et al. 2022). Sheep producers often stock at rates that align to expectations of decile 2–4 (low rainfall) seasons. This is driven by the high perceived and actual downside risk associated with sustaining livestock through poor seasons. Filling feed gaps has been one of the top WALRC priorities for the last four years. Strategies to address key nutrient gaps are likely to give confidence to mixed farmers to increase whole-farm stocking rates while potentially lowering the risk profile of their enterprises. Drought-tolerant native shrubs, grown on soils that are marginal for crop production, provide nutrients to complement, and thereby improve the feed conversion ratio of crop and pasture residues during summer/autumn. These shrubs lift farm profitability by reducing supplementation requirements, allow deferred grazing of regenerating pastures, and buffering between-season variation in forage supply. They provide vitamins and minerals that are limited in summer and assist animals to manage oxidative stress.
Previous research has shown that sheep offered Anameka^TM saltbush or rhagodia, while grazing cereal residues, maintained weight, and had 20% greater wool growth than sheep offered cereals alone (Li et al. 2018). In respiration chambers, inclusion of rhagodia led to 26% less methane (Li et al. 2018). Barriers to adoption of shrubs include the high opportunity cost of using soils that are suited to cropping, the up-front cost of establishment, uncertainty about agronomic and grazing management and a lack of on-farm data quantifying benefits.
This project conducted research and extension to address these barriers. The target audience was producers, producer groups and the wider livestock industries. The information that has been gathered in the project has been used to inform mixed producers of the opportunity to utilise shrubs to overcome nutrient gaps and give them confidence to increase stocking rates. We will identify elite seed lines for potential commercialisation and develop guides to optimise establishment, productivity, and grazing management.

Objectives

This project aimed to conduct collaborative research with producers to:
- collect paddock scale productivity and economic data demonstrating that sheep and/or cattle can utilise shrubs to improve productivity and utilisation of crop residues
- quantify benefits arising from using fertilisers and/or adapted annual legumes within shrub systems
- investigate opportunities to halve establishment costs through seed lines that can be planted in nurseries or direct seeded.

There was a significant industry engagement activity. Increased adoption of shrub systems by producers will congruently improve landscape function and reduce the impact of dryland salinity.

Key findings

Benefits to industry

Benefits to industry arising from this research include:
• Development of extension products to support the adoption of shrub systems on marginal soils to improve whole-farm stocking rates and manage seasonal risk.
• New shrub genotypes that have the capacity to double productivity and enable cost-effective direct seeding, potentially reintroducing higher feeding value native shrubs to rangeland areas.
• Information regarding shrub grazing management and fertilisers to assist producers to optimise system productivity.
• Adoption of these systems offers benefits like reduced dryland salinity, enhanced ecosystem function, possibly reduced methane emissions (rhagodia), higher animal welfare, and better eco-credentials for meat and wool production.
• Raised awareness and provided information to support adoption of shrub systems. Over four years we delivered 2068 face to face contacts (1,040 producers and 1,028 industry representatives) over 48 events in three states. We also delivered a Landline TV story and TV news stories, nine radio interviews, three You-tube-style communication products (https://vimeo.com/733868413), six magazine articles (in Feedback and Beyond the Bale), 43 online or newspaper media articles and more than 30,700 social media views.
• Strong adoption of Anameka^TM shrubs, with sales doubling since 2019, leading to the planting of six million shrubs on 8,500ha by 328 producers.
• Research resulted in eight scientific publications, with three more in progress, and presentations at national and international conferences.
• Shrub systems are incorporated into MLA's 'Shade and Shelter' projects, focusing on twin lamb survival. Future Drought Fund support was obtained to establish six producer-scale Anameka^TM saltbush systems demonstrations in areas of NSW and WA where adoption is low, but the opportunity is high.

MLA action

We believe that we have the information, technology, and genotypes to progress direct seeding (for agricultural and possibly rangeland zones). We hope to continue this work in partnership with industry, possibly through a WA Agricultural Research Collaboration Application (submitted June 2023) and CSIRO Drought Mission support. We will maintain active conversations with MLA and AWI to discuss opportunities for co-investment.

Future research

As a result of this project and associated industry consultation, we recommend that:
• The commercialisation of an elite saltbush seed line – or a combination of several lines. Discussions with industry are underway to scope the appetite for the product and seed production and sales logistics.
• While we have identified elite rhagodia genotypes that have high biomass production and nutritional value and tolerate deep infertile sands, they remain relatively unpalatable to sheep. We have identified a cohort that have higher palatability than the original population, however, these are grazed after the majority of saltbush has been consumed. We suggest waiting on the outcomes of the ‘Shade and Shelter’ MLA projects before deciding on a commercialisation strategy. More work is required to understand why sheep do not eat the shrubs and their role in methane mitigation. There is an opportunity to select a genotype that is very productive on marginal sandy soils and reduces methane emissions.
• The key findings regarding shrub management and agronomy are already being presented to industry. The variability in fertiliser responses across sites is likely due to the deep-rooted shrubs accessing fertiliser at depth. Producers are unlikely to sample soils to these depths, so messages need refinement.
• Use of adapted annual legumes remains a key opportunity but weed management has emerged as an issue. Matricaria (Globe Chamomile) is a threat to shrub systems in the eastern wheatbelt of WA. We recommend the development of herbicide and weed management recommendations for shrub systems.