Trials focus on low to medium rainfall areas

The group inspected Murdoch University crop trials that are part of the Dryland Legume Pasture Systems national research project.

The project, which aims to boost profit and reduce risks on mixed farms in low and medium rainfall areas with newly discovered legume pastures and innovative management methods, originated from the Rural Research and Development for Profit scheme offered by the Federal Department of Agriculture.

Facilitated by the Grains Research and Development Corporation, with Meat and Livestock Australia and Australian Wool Innovation co-investors, Murdoch University is collaborating with CFIG, along with, ASheep Esperance and the Mingenew Irwin Group in the Mid West.

Murdoch research manager for the Centre for Rhizobium Studies, Ron Yates, said the project was introducing new annual pasture legumes for low to medium rainfall areas on different soil types and using innovative establishment methods such as summer sowing by manipulating hard seed breakdown.

"We're basically getting new options that present lower cost for farmers, such as harvesting their own pasture seed so they don't have to go through the expensive operations of cleaning and scarifying the seed," Dr Yates said.

The project is broken up into five outputs, with the first being based on annual pasture development where the Murdoch team is domesticating wild pasture legumes.

Some of this work was shown on the field day at Narembeen, a site run by Murdoch University pasture breeder, associate professor Bradley Nutt.

The aim of output one is to assess a range of non-commercial species and varieties as productive and persistent alternatives or complements to annual medics on fine textured soils in low rainfall areas.

"Brad is evaluating hundreds of accessions of pasture legumes that mainly originated from the Mediterranean basin and developing new legumes for our farming systems," Dr Yates said.

"Most options for the low rainfall areas such as Narembeen are restricted to subclover and medics but some growers are now trying alternatives such as serradella, biserrula and vetch."

These crop trials are attempting to provide growers with other options.

Assessments of the trials include vigour ratings, dry matter production, nutritive value both green and dry, noting any insect activity and seed yield.

The best performers at the site so far include helmet and bladder clovers, sickle pod fenugreek and scimitar burr medic.

"A lot of the time we research legume pasture plants that haven't been domesticated before and we have to fit them into our system in agriculture," Dr Yates said.

"Attributes we look for are insect tolerance, tolerance to pathogens, deep root systems, aerial seeding and lots of seeds so we can header harvest or we look at the size of the seed as well if we want more passage through the animals.

"We look at not only the climate, including maximum and minimum temperatures and rainfall, but also what soils they've come from.

"Serradella, for example, are more suited to lighter soils and while other legumes grow better on heavier soils we only really find out their fit by trials in-situ."

Dr Yates said it was vital to match up the new species with the correct rhizobia, the bacteria that forms a symbiosis with the plant host to provide nitrogen.

"We must carry out a duty of care, where if they are to release an inoculant, to make sure it's not to the detriment of an existing pasture or crop legume symbiosis," he said.

One legume Dr Nutt previously developed, which was also included in the trial, was hard-seeded pink serradella Margurita.

"Pink serradella is normally a soft seeded plant, and like most plants in cultivation doesn't have any seed dormancy, because you want the seed to germinate when you put it in the ground," Dr Nutt said.

"I reversed-engineered this in a way where I pulled out hard seed producing genotypes and the result was Margurita.

"By using a technique called summer sowing (drilling the pod in late February) we utilise the dormancy of the serradella because the seed is inside a woody pod.

"Normally with hard seeds we scratch the seed coat to get them to germinate when we sow a pasture, but with serradella that's a problem because you have to get the seed out of the pod.

"So instead we harvest it while it's a 90 per cent dormant seed, and then if you sow it into the soil in February or March that exposes the seed to the natural conditions that break the hard seed dormancy."

Dr Nutt said this had a two-stage effect - one being exposed to high temperatures for a period of time and the second being exposed to fluctuating temperatures that happen over summer and autumn, which on the bare soil is from 10-15 degrees at night to about 65 degrees in the middle of the day.

"That bounce in temperatures every day is what opens up a particular organ on the seed to make it germinable," Dr Nutt said.

Dr Yates said serradella was also good when looking at nitrogen transfer into the following crop.

"When we do our calculations we look at subclover or medic and they're usually 2.5 per cent nitrogen," he said.

"But most of the time when we look at serradella it's up three to four per cent, so we're getting more bang for our buck and a lot more nitrogen into the following crop."

The second output of the project looks at the benefits of pasture legumes to crop production systems and is managed by Murdoch University research officer Rob Harrison.

The trial at Ardath started in 2018 and will run over four years with 20 plots separated into two banks of 10 plots.

"The four year rotations with different treatments that include legumes is mainly looking at the benefits of nitrogen in the rotation, but also what the break gives cereal crops, including weed control, nematode reduction, root disease reduction and the big ones for us are yield and grain protein," Mr Harrison said.

"We're also looking at rooting depth of the pastures and the impact on water usage, but we are still gathering that data.

"So far it looks promising, we might have some alternatives to pasture cultivars already out there.

"We've seen some good results with the rotations of the legumes with cereals, as there's already been a reduction in root lesion nematodes, and some of the root diseases."

The project's output three focuses on the benefits of legumes with animal production while output four is managed by CSIRO and involves the modelling of these plants in the system to look at maximising profit.

"Output five is about extension, so where we go out to field walks like today and talk to growers about how you introduce and establish these new pasture legumes in the system," Dr Yates said.

"We usually do quite a few field walks in a year."

As well as CSIRO, the Department of Primary Industry and Research Development (DPIRD) is assisting Murdoch University with its research.

Fourth-generation mixed farmer, Michael Mortimore, who runs his 7000 hectare property with his father, Ian, attended the field walk to see what other farmers were doing and if there were any new developments coming from the research that could help improve his crops.

Mr Mortimore's family's farm, 20 kilometres north east of Narembeen, crops wheat, barley, oats and lupins.

"It's been a hard year, but I'm looking at options for heavy country with vegetation," Mr Mortimore said.

"You don't want to jump in the deep end straight away, but rather see what other people are doing before you have a crack yourself.

"Our crops are hanging on surprisingly, pulling moisture from I'm not sure where, but it's getting to a critical stage and there's nothing too promising on the horizon, so it's probably going to be a well below average year.

"Obviously it was a hard start this year, but there was a bit of optimism in June, July and into August as the crops took off and looked OK, but unfortunately we haven't had any rain since, and a couple of low to mid 30 degree days with hot dry winds has turned things for the worse.

"But there's always next year."