Taking no-till off the plateau
GroundCover™ Supplement Issue: 64 | 07 Aug 2007
Two new streams of research by the Western Australian No Tillage Farmers Association (WANTFA ) aim to answer grower and wider industry concerns about inadequate soil stubble cover, lack of viable options for crop rotations and herbicide-resistant weeds.
The projects - 'New Frontiers No-Till Farming Systems' project and 'Cover Crops for No-Till Farming Systems' - are both supported by the GRDC and, as is appropriate, involve collaboration with other research organisations. Recommendations from the Cover Crops project - about cheap-to-manage and reliable species - are in the early planning stages for testing in longterm no-till trials. One is to be on sandplain soil, in collaboration with the Mingenew-Irwin Group, and the other on heavier soils near Cunderdin.
According to WANTFA scientific officer Dr Ken Flower, an estimated 86 per cent of WA growers are using no-till for at least part of their cropping programs, recognising the system's benefits of timely operations, moisture harvesting, erosion control and higher yields.
"But other beneficial effects growers expected in the longer-term from no-till - such as increased organic matter and more biological activity in the soil - have not been realised in many cases, and production appears to have reached a plateau," Dr F lower says.
"Cereals, particularly wheat, currently dominate the Western Australian cropping scene, because growers have moved away from rotational options like canola and lupins through a combination of poor prices and low reliability.
"You can nearly always expect to get some return from a wheat crop. And at the same time the increasing threat of herbicide resistance has prompted some growers to question the sustainability of no-till in WA."
Dr Flower says all these concerns prompted WANTFA to commission Rolf Derpsch, an international Paraguay-based no-till consultant, to carry out a situation analysis of no-till in WA.
Dr Derpsch identified lack of soil cover, inadequate diversity in rotations, herbicide resistance and weed control as the major challenges for Western Australian no-tillers, with other problems being over-grazing, stubble burning or baling and old-fashioned cultivation. Dr Derpsch suggested notill may have reached a plateau with the use of tined seeders - particularly with limited rotation options - and that in addition, tines would not be able to cope with the required increase in crop residues required for the no-till system to progress.
His recommendations were for no-till systems in WA to be essentially based on full stubble retention, diverse rotations with cover crops, a more holistic approach to weed management and seeding to be carried out with discs.
He also recommended that longterm research be carried out to improve the quality of no-till and quantify its benefits, which resulted in the New Frontiers No-Till Farming Systems project.
[Photo (left): Meeting the challenges of WA no-tillers: Dr Rolf Derpsch (left) and Dr Ken Flower inspecting poor summer weed control through conventional tillage.]
Region North, South, West
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