This project demonstrates mixed species pastures in medium- to high-rainfall environments and the drought resilience benefits they provide to soil, pasture longevity and productive use of out-of-season rainfall.

Mixed species pastures offer opportunity to extend the pasture growing season, increase ground cover, increase plant species diversity, improve livestock nutrition through offering a diverse range of plants, and increase soil health and function through providing a greater number of plant types with increased diversity of root structures and associated soil-based microbial ecosystems. These healthy and diverse systems are better able to use and retain available water and are more able to respond to variable or challenging seasons.

The project aimed to assess and communicate the value of pasture species/mixes in local farming systems. To achieve this, various pasture species/mixes were evaluated at four field demonstration sites, two by BIGG (Angaston, Birdwood) and two by MNHRZ (Navan, Farrell Flat).

The trial assessment aims were achieved, with the pasture treatments being assessed throughout the season for dry matter production and quality at all sites, including residual soil water and nitrogen at the MNHRZ sites.

Project description: 

The primary objective of this project was to assess and communicate the value of pasture species and mixes in local farming systems. Various pasture species/mixes were evaluated at four field demonstration sites in 2022:

• BIGG, Angaston (medium rainfall – major site)
• BIGG, Birdwood (high rainfall – minor site)
• MNHRZ, Navan (cool environment site)
• MNHRZ, Farrell Flat (cold environment site).

Key achievements and results: 

BIGG sites

BIGG’s major site at Angaston assessed two single species (oats, ryegrass) and three multi-species (oats/ryegrass, oats/ryegrass/clover, oats/ryegrass/clover/brassica herb) at five timings throughout the season.

The treatments that produced the highest total dry matter yield for the season were:

• oats/ryegrass/clover/brassica herb (4557 DM/ha)
• oats/ryegrass/clover (4409 kg DM/ha).

These were also the treatments with the most plant diversity (a mix of ten and six varieties, respectively).

Although oats alone produced the lowest total dry matter yield (3183 kg DM/ha), this treatment did produce reasonable dry matter yield early in the season.

In comparison, ryegrass, either as a single species treatment or as a key component within the three multi species treatments, performed strongly later in the season.

Feed quality analysis determined marginal differences between treatments at each sampling time, however averaged across the season, oats/ryegrass/clover/brassica herb had the highest feed quality. With this treatment also producing high dry matter yields, both early (likely due to the contribution of its brassica content) and late (likely due to the contribution of its ryegrass content) in the season, it appears to be a good option to help graziers fill the traditional winter feed gap while providing a longer grazing period in a season like 2022 at Angaston.

The results also validated that within a multi-species pasture mix, different species perform well at different stages of the season and, compared to a single-species pasture, can better respond to seasonal variation.

MHNRZ sites

MNHRZ’s sites at Navan and Farrell Flat determined dry matter production of individual pasture and forage species, and mixes at three timings throughout the season. The species included cereals, ryegrass, brassica, pasture legumes and forage legumes.

Key outcomes relating to dry matter production were as follows:

• Early season
  Cereals were the best source of early season feed, with barley varieties producing the highest levels of dry matter compared to other cereals. Higher seeding rates can result in significantly higher dry matter production. Of the mixes, cereal-based mixes provided the highest amount of dry matter.
• Mid-season
  If pasture production is not required until 8-12 weeks into the season (mid to late winter), then brassica species can produce high levels of dry matter.The time period to grazing will depend on the environment, with the Navan site accumulating more dry matter in a shorter period of time.There was no significant difference in recovery of cereal species at this timing (as measured by yield of previously mown treatments), and, in some cases, recovery of mown canola/brassica species matched recovery of cereal treatments.Unmown canola/brassica species outperformed legume species with the exception of Morava vetch.

  Of the mixed species, cereal mixes recovered best from initial grazing compared to the canola/brassica and vetch mixes.

• Late season
  All legume, ryegrass and beet species performed equally well at Navan, suggesting that for late-season feed following earlier grazing, selecting the cheapest option out of the species may be the best approach. This will reduce financial exposure in a dry spring, where performance may be more limited than it was in this project.All pasture mixes performed well at Navan, with the Tetrone ryegrass/Persian clover mix also performing well at Farrell Flat, where it recovered extremely well from a severe mowing treatment.

At the end of the season, soil testing was also conducted at Navan and Farrell Flat to determine residual soil water and nitrogen (given this may influence future rotational decisions and input costs in following crops). Analysis was completed for both sites, assessing the 0-60cm plant available water and nitrogen, and 60-100cm plant available water.

Navan soil water results were impacted by late season rainfall with soil nitrogen results indicating some trends towards high nitrogen levels with legume species, however these differences were not significant.

Communication and extension

Communication was a major focus of the project, delivered through crop/pasture walks at the BIGG and MNHRZ sites, and via associated articles and presentations. A highlight was approximately 200 farmers and 40 agribusiness reps/advisers attending the demonstration site crop/pasture walks that both groups held in 2022. This gave attendees a great opportunity to learn about and see first-hand the pasture species and mixes that perform well in their region.

Having trial sites established in different environments also proved valuable. For example, results from the MNHRZ trials established at cool (Navan) and cold (Farrell Flat) environments determined that, due to slower growth rates early in the season in cold environments, brassica production was compromised, making cereals a better pasture production option. This type of information gives farmers increased confidence to implement strategies best suited to their environment. It also helps inform their pasture seed choices and immediately put these into practice.

Better pasture choices and growing more productive, high-quality pastures not only helps farmers better meet their livestock production needs, but also gives flexibility to retain extra stock or convert it into fodder if excess feed is available. This can then fill seasonal livestock feed gaps or be saved for dry times. Growing adequate pasture also gives the best opportunity to maintain paddock groundcover, providing landcare benefits. Altogether, this helps build the resilience of local farming systems.

Other key groups who visited project sites included: University of Adelaide agricultural science students at both Navan and Farrell Flat; the Federal Drought Hub Advisory Committee, who visited BIGG’s Angaston site in August 2022; and the Federal Minister for Agriculture, Forestry and Fisheries, visited the Angaston site in November 2022.

BIGG’s project results were also recently communicated to over 50 producers at its annual conference in February 2023, with MNHRZ presenting results at its Autumn 2023 update.

Collaboration

A secondary objective of the project was to foster collaboration between BIGG And MNHRZ and the development of wider partnerships. Examples of achievements in this area included:

• A new University of Adelaide project (Pasture Optimisation for Drought Solutions) co-located its ‘Novel pasture species’ trial at BIGG’s Angaston site.
• MNHRZ’s Farrell Flat demonstration site was incorporated into its Grains Research and Development Corporation / SA Grain Industry Trust-funded MNHRZ Frost Learning Centre. This added value for both MNHRZ projects, as livestock is a key risk management tool for growers who have significant areas with high frost damage/frequency on their farms.

Further information:

• Project Technical Report: Mixed Species Pastures Demonstration Sites
• BIGG case study: Productive multi-species pasture at Marananga. In 2021, Marananga farmer Matt Neldner sowed half a paddock to a multi-species pasture and the other half to a conventional ryegrass-based pasture. In 2023 monitoring revealed increased grazing of the multi-species pasture.
• BIGG Mixed Species Pastures webpage