Kay Ansell reports on a trial which is putting theories covered at
the conference to the test.
Zero till versus conventional farming – which works best? The Birchip
Cropping Group (BCG) is putting both to the test, along with two other
farming systems, in a long-term trial.
Mirroring the fortunes of the grains industry, however, the drought has
dramatically affected the financial results of the trial, which has run
for four years and will continue for at least another two.
In 2002, only one system (conventional) harvested any crop and zero till
has so far been the poorest economic performer – although this is
only one of the sustainability yardsticks being measured.
In a joint paper analysing the trial, BCG farming systems economist Fiona
Best reports that one of the biggest challenges for the trial and the
farming community revolves around soil conservation versus moisture conservation.
She says this was evident in the drought year 2002 when many cereal crops
grown on fallow yielded some return, while in the same year the Mallee
soil suffered at the hands of severe wind and dust storms. In what is
believed to be a first for the southern Mallee and northern Wimmera, the
trial pits grower against grower in “championing” their chosen
By measuring physical production, economic performance and natural resource
base sustainability, the trial aims to help growers decide which of the
four approaches works best overall for dryland farming regions in the
300 to 450mm annual rainfall zone in Southern Australia.
The BCG believes the grower-driven nature of the project will encourage
positive changes to farming practice to occur more rapidly. The four systems
“championed” by their respective growers are:
The contestants share 20 hectares split into one hectare plots on the
McClellands’ property, 30km north of Birchip. Crop intensity, livestock
grazing and tillage are among the distinguishing characteristics of each.
Zero till has 100 percent crop intensity, no livestock, full stubble
retention and one-pass, knife-point seeding. Reduced till has 80 percent
crop intensity, minimum tillage and opportunity livestock.
Fuel burners is a conventional, cereal-based system with 60 percent crop
intensity and opportunity livestock. Hungry sheep combines 70 percent
crop intensity with intensive grazing by livestock.So far, the hungry
sheep system has achieved the highest average gross margin.
The zero till system has had the greatest area sown to pulse and canola
crops, sowing on average 50 percent of available area. This system also
delivered the lowest four-year-average gross margin of $27.20 per hectare,
while reduced till returned $125.70 per hectare and fuel burners “achieved”
$142 per hectare.
Weeds, disease, nitrogen and soil water, and soil microbial activity
are being monitored, along with soil compaction and organic carbon levels
to determine the sustainability of each system in relation to the natural
“Despite early trends it would be impossible at this stage to suggest
that one system is more superior than the others,” Ms Best says.
It may take at least 10 years to know the long-term performance of each
system, especially with regard to environmental aspects.
For more information:
Fiona Best, 03 5492 2787, firstname.lastname@example.org,
GRDC RESEARCH CODE BWD18, program 4
North, South, West