SOUTH Australian farmer and Nuffield Scholars of Australia immediate past president Brendan Smart is involved in a sub-surface drip irrigation trial project for growing lucerne which could have huge ramifications for growing irrigated crops in low rainfall areas.
Brendan has received $105,000 (40pc of the cost) from the Federal Government as an innovation grant to help him establish the trial which is on 44ha (100ac) of land.
He has already laid 430km of dripper tubes with a sub soiler.
The tubes are laid 25cm (10in) deep and are spaced one metre apart.
The idea is to keep the root zone of lucerne plants moist throughout the growing season.
He has divided the trial area into water sections of 4ha (12ac) and has the ability to apply 10mm per day to the root zones.
"But we think 3mm should be enough to keep it moist without soaking the zone," Brendan said.
"It could fluctuate up to 8mm."
According to Brendan, the lucerne plant's production comes from the lateral roots with the tap root playing the role as a moisture seeker.
"The tap root is there for survival not production," he said.
Brendan is one of Australia's largest lucerne growers harvesting 500ha of irrigated lucerne seed and 400ha of non-irrigated lucerne seed for the export and domestic markets.
He has a total of 1500ha of arable land for crop and livestock production, which is mainly prime lamb.
The reason for Brendan's trial of subsoil drip irrigation is that in the life cycle of an irrigated lucerne plant it either has a lot of moisture or not enough, during irrigation flushes or centre pivot cycles (up to 10 during the growing season).
"It can be a bit of feast or famine for the plants so we thought the drip irrigation would provide a more even growth," Brendan said.
Brendan also is integrating computer plant analysis in the trial with the computer determining how much water a plant needs from information received on the optimum moisture requirements for a plant from start to finish.
"At the moment we've got a feel for it so we're hoping to refine that particular aspect over the next two years," Brendan said.
"We'll treat each section with different subtle treatments during different growth stages of the plant's growth.
"So we will play around with water rates to see what the plants needs."
The other important aspect, and this got the government's attention, is that with drip irrigation there is no flooding of the soil, significantly cutting water use.
"And the weeds won't germinate as much as they would with a more moister topsoil," Brendan said.
"And if they do we believe the micro-environment of the lucerne canopy will mitigate against weed growth plus reduce pests and diseases."
Another trial with computers will be to monitor nutrient needs of plants during their growth stages.
"That's into the future but we think that's a possibility," Brendan said.
The project comes under Brendan's company the Smart Group, which embraces cropping, livestock, grapes and wines.
Brendan was in Perth recently to check out the latest product developments of WA manufacturer Ausplow.
He is onto his fourth DBS precision seeder since starting in 1996 and declaring the DBS the best machine to establish lucerne.
His current model is a 12.1m (40ft) model linked to a three bin Ausplow Multistream PDS.
After trying liquids five years ago and not getting a response, Brendan is thinking of having another go in 2006, possibly with a new PDS.
His enthusiasm for the DBS hasn't wavered as he recalled during a recent trip to WA that in 2002, his barley crop averaged 4t/ha.
"It was a spectacular crop in a year when the whole concept of the DBS came together," he said.
"We had good nutrient input and the soil structure was sufficient to carry a heavy crop which all went malt.
"We've found that at the end of the third year of using the DBS there is significant differences to soil structure and crop vigour.
"I think we undersell the subsoil management we get by using the DBS."