Stressing lucerne plants during summer by manipulating irrigation watering is critical for good seed set.
But each variety has a different tolerance in how far they can be stressed without losing yield potential.
A new three-year Lucerne Australia trial hopes to find the optimal levels for maximising seed and forage production and how it compares to existing irrigation practices.
Simon Allen – a member of the LA executive committee – is hosting the trial in a paddock just south of Keith.
He believes it may be possible to save 15 per cent to 20pc of water pumped each season on some varieties by altering the regime of border check (flood) irrigation.
“It is a complex decision based on seasonal factors but we need to work out how far is too far in drying out the plants,” he said.
“In the last bay (watered the least) we may see that we have pushed beyond commercial seed production.”
Like most growers Warrawee Park uses data from soil moisture probes as a “good tool” for irrigation scheduling.
The Sentek probes, which measures moisture to at depth of at least 80 centimetres, were installed by the Alpha Group, Keith, who also provide ongoing data.
But Mr Allen says it is also important to look closely at the plants in the paddock when making watering decisions.
The independent trial, which is funded by AgriFutures Australia’s Pasture Seed Program was sown late last month by Kalyx Australia.
It is evaluating 29 plant breeders rights varieties from seven different marketers.
These will be benchmarked against two public varieties, Siriver and Aurora, for herbage and seed production.
The trial will also include a gross margin analysis of each modified irrigation management practice.
Mr Allen says he was keen to host the trial to “give back to the industry” and hopes it will deliver some good results.
“The feedback from our members was they wanted to see more of these independent trials,” he said.
“The marketers also get some good data on forage and seed yields.”
Mr Allen says underground water levels has remained fairly static in the area and there are no foreseeable allocation cuts, but growers needed to continue to use the resource responsibly.
“Pumping costs like diesel and power all add up too,” he said.
Lucerne Australia chairman Bruce Connor said growers were sometimes reluctant to adopt new varieties but the data from this trial would give them more information on seed yield under Australian conditions and different water stress levels.
Good production fit with lucerne seed
Lucerne seed prices may be back from the record heights of nearly $8 a kilogram in 2016, but Warrawee Park’s Simon Allen is still confident about the industry’s long-term future.
Despite major buyer Saudi Arabia not being active in the market and drastically reducing its forage production to reduce its water usage, the Keith grower still foresees solid demand going forward.
“If it is not our traditional customers, there is a good chance their neighbours may potentially put their hands up, as long as they have the water,” he said.
“There are still a lot of dairy cows there that need to be fed (in Saudi Arabia).”
Mr Allen says the Upper South East is well placed for lucerne seed production with its combination of free draining loam soils and favourable climate, particularly summers, which are generally warm to hot and dry.
Lucerne also tolerates salinity better than many other irrigated crops, with the pumped water on Warrawee Park ranging from 3000 to 5000 parts per million.
It is about 3500ppm at the trial site.
Warrawee Park has about 400 hectares of border check irrigation dedicated to certified lucerne seed.
This is run in conjunction with its winter cropping program and a self-replacing flock of 3200 Merino ewes.
Mr Allen says their sheep and lucerne complement each other well with the ewes run on lucerne stands from seed harvest through their April-May lambing, until mid July.
The paddocks are then winter cleaned, shut up for a hay cut and then a seed crop.
