No-till needs more effort, says expert
GroundCover™ Issue: 59
[Photo (left) by Brendon Cant: Six weeks in the field: No-till expert Rolf Derpsch.]
WA growers have well and truly
secured their place as innovators in Australia"s agricultural history, especially with their energetic adoption of minimum tillage from the late 1970s. The Dowerin and Newdegate field days became showcases for new ideas and new machinery - often designed and built on-farm - as the state"s graingrowers, backed by new herbicides like the non-residual knockdown Roundup, pioneered a whole new farming system for Australian soils.
In the early 1990s when no-till began to wane as yields appeared to be suffering and there was concern about an over-reliance on chemicals, a group of growers formed the WA No Till Farmers Association (WANTFA), believing the answers lay in pushing the science and boundaries, not in retreat.
Their doggedness has led to an estimated
80 per cent of WA growers now using either
no-till or reduced tillage. The adoption
of the system nationally is credited with
significantly lifting the grains industry"s
sustainability. No-till growers talk
enthusiastically about the changing colour
and increasing softness of soils in which organic carbon levels have been rising.
However, in recent years the benefits
of no-till have again appeared to plateau,
and earlier this year WaNTFA sought
help from world-renowned Paraguayan
no-till expert Rolf Derpsch.
After spending six weeks assessing the situation, travelling 4000 kilometres through WA and also South Australia (with the SA No Till Farmers Association), Mr Derpsch delivered a "good but can do much better" report card.
In a nutshell, he said Australian growers" flexible approach to no-till - using knife points instead of discs to get that little bit of extra soil turn, or still running sheep - was compromising the system. "I saw too much bare soil," he said.
Mr Derpsch said that for no-till to reach its potential in Australia, rotations needed to be more diverse. "Also, cover crops should be incorporated to ensure that the soil is covered 100 per cent of the time, and discs need to replace tynes, so higher rates of residue can be handled," he said.
Mr Derpsch said the advantages from no-till farming came from constant soil cover - not the actual tillage method.
Region North, South, West