Case Study: Dryland Legume Pasture Systems 2020 Sites Cascade & Grass Patch

Sarah Brown (ASHEEP) interviews Mark Walter & David Vandenberghe.

Since 2018, ASHEEP has been taking part in the Dryland Legume Pasture Systems (DLPS) project in conjunction with Ron Yates and his team at Murdoch University. The project is focused on boosting profit and reducing risk on mixed farms in low and medium rainfall areas through the trial of newly discovered legume pastures.

We had the opportunity to visit the trial site at David and Katherine Vandenberghe's Grass Patch property at the Winter Field Walk this year. Rob Harrison took us through the varieties on show and there was a lot of interest from producers to see more of them become commercially available. There is also a second trial site at Mark and Liv Walter's in Cascade, which is looking at Nitrogen transformation.

Here we interview Mark and David to get their take on the trials and the impact that the project has, or could have, on their farming systems.

Mark Walter - Cascade - Nitrogen transformation trial

The DLPS site at the Walter's was established in 2018 with Medic pasture, mostly self-regenerated. The trial also included small strips of Trigonella. 2018 turned out to be a poor year for pasture, with 7mm of rainfall in May and 15mm in June. This resulted in a poor initial establishment which continued for the remainder of that year, with subsequent low biomass produced.

2019 continued the rotational trial at Walter's - cereal, fallow and pastures (vetch and medic). In 2020 it was all cropped to sceptre wheat with N rates to determine responses in yield, protein and screenings.

How has your trial site performed and what seasonal conditions have impacted it?

Unfortunately the trial site has experienced our three lowest rainfall years ever, which has impacted the biomass growth of the pasture. The wheat crop that has gone in over it this year looks reasonable and may be average, but I’d say any differences will be more a fallow effect than anything. What has caught your eye from the trial? The trial has shown that medic does not perform in our system anymore. We had vetch sown around the outside of the site in the first year which went well considering the rainfall compared to the Medics. The Trigonella has also performed well on this soil type and we will be excited to try some when it is available. I understand the concept of the trial is to grow nitrogen for the following crop, but I think that due to the seasonal conditions it will be hard to prove that from this site.

How do you see the learnings from the trial impacting your system?

In that same soil type we have traditionally had medic pastures. Over the last ten years we have cropped these medic pastures to an extent where plant numbers are no longer viable. We have tried biserrula on this soil type which has performed well on the sandy soil types and gravels, and produced seed well, but has struggled to produce much biomass, plus the photo sensitivity problem.

The rotational trial in 2019 at the Walter's.

We have had good success with Santorini and Margarita Serradella on our sandier soils and will continue to establish these. On the heavier clays we have grown mainly RM4 vetch. There is a significant cost to establishing Vetch every year but we are finding we get a longer season length, grazing from April to October (if it remembers to rain) and significantly more biomass on a consistent basis.

We have also found that subsequent cereal crops are consistently up to 1 t/ha better the year following medic or canola and between 1% - 2% better protein. This has meant that for two cereals after the Vetch we use significantly less nitrogen (up to 50 units less) than after a canola.

What further research would you like to see come out of the trials?

We would like to see the progression of the new varieties continue. There are not a lot of options for this soil type other than medics and now vetch. Seeding all your pasture, every year, shouldn’t be ruled out as it is achievable for most people

now at a low operation cost if there is a biomass and rotational benefit. I think Trigonella could have a good fit on these soils as well as long season vetches.

Making nitrogen decisions on crops is one of the most contentious issue that we have every year. Any research into how much is available after a good pasture in the first and second cereal crops following is excellent information. We need

simple ways of knowing this rather than guessing.

David Vandenberghe - Grass Patch - Varieties & seeding trial

Run us through your trial site.

Lotus in the trial site at the Vandenberghe's.

The trial site has run at ours in 2018, 2019 and 2020, trialling a wide range of new legume varieties. Initially we started with 40 genotypes ranging from Vetch to Scorpiurus, Trigonella balansae, Bladder Clovers, Medic, Serradella, Lotus, Helmet Clover and more.

Many of these genotypes have never been grown in Australia. Initially seed was collected in the early 90s, mostly from the Mediterranean. Then it was a process of picking out a few possible winners and refining that down. So the second year the species of the most interest were resown, down to the third year which is most likely the ones they will commercialise (looking to be 2 or 3). Frano Serradella has already been commercialised.

How has your trial site performed and what seasonal conditions have

impacted it?

It has probably underperformed in the fact that we have had three very dry starts and low winter rainfall. In saying that, the first year there was some carry over sub-soil moisture which allowed the Trigonella balansae to stay green until almost January. Last year the site was impacted severely by frost and a terrible spring.

Scorpions Tail in the trial site at the Vandenberghe's.

What has interested you from the varieties planted in the trial?

Trigonella in the Grass Patch trial site.

Definitely the Trigonella – I like the fact that it can carry on into the spring and it is aerial seeded which allows us to harvest it easily. The other thing I would be very interested in is mixed swards; multiple species that will complement each other to give us a better feed base throughout the year. To get full benefit we have to be able to early-seed a variety. We need to have species that can be summer sown to get early feed and utilise what moisture there is.

Is there anything of note in relation to seeding techniques?

Some of the larger-seeded varieties need to be seeded a little deeper. For example, the Snail Medic needs to be seeded a little deeper than what I had thought. Early competition is also critical as can be seen from areas in the trial where the background Medic is dominating. It's also crucial to get exactly the right inoculant – the Scorpiurus struggled because it didn’t get the right inoculant.

Have you planted any of the new varieties from the trial yourself?

I haven’t yet – the only one that has been released is Frano. Certainly I will once more have been commercialised. I’m really liking the look of the Trigonella and a short-season Bladder Clover.

The trial has led me to look further afield to different varieties such as Sulla (a Biannual legume that grows like rocket fuel with massive tap root). It stays alive for 2 years at least, it dies off in summer but responds really quickly to rain from the root stock and you just about can’t kill it. I have bought half a tonne to seed 150ha as an experiment. It will be good for the autumn and spring feed gaps. It’s a bit like lucerne but tougher and loves sodic clay.

How do you see the role of the legume benefiting your cropping and

livestock operation?

Definitely by providing extra nitrogen for the crops and also by building up organic carbon. Another important aspect is to fill in the feed gap with some of the deeper-rooted varieties like Serradella and Trigonella.

Sulla

It’s obliviously too early to be working with the varieties from the trial, but in future we look forward it and the opportunity to increase livestock numbers as a result. It is really hard this time of year with the feed gap we have before the stubbles are available. If we could keep the stock going for an extra three weeks it would make a huge difference.

Another benefit is going to be reducing wool contamination - clover burr is a big issue. It looks like for most of the legumes in the trial this won’t be an issue.

What further research would you like to see come out of the trials?

I’d definitely like to see more done on herbicide applications and also seeding complimentary species together to establish a good mix instead of just looking at monocultures. I’d like to see the trial continue and maybe even collect more species overseas each year to see if we can find something new. We need funding to go into these sort of things to find the next successful legume to take production up to the next level.

This project is supported by funding from the Australian Government Department of Agriculture and Water Resources as part of its Rural R&D for Profit program, the Grains Research and Development Corporation, Meat and Livestock Australia and Australian Wool Innovation. The research partners include the South Australian Research and Development Institute, Murdoch University, the Commonwealth Scientific and Industrial Research Organisation, the WA Department of Primary Industries and Regional Development, and Charles Stuart University, as well as grower groups.