A follow-up survey by Vanclay and Hely (1997) found
the number of drills that could handle more than
2 t ha1 of stubble had almost doubled to 28% over the
3-yr period. Of more concern was that only 7% of drills
in the Central West of New South Wales could handle
stubble of 3 t ha1. A considerable disincentive to
increased stubble retention is the high cost of tillage
and sowing machinery to handle stubble densities
greater than 3 t ha1. This amount of stubble can be
left after just 2 t ha1 of wheat have been harvested.
Adoption of stubble retention will continue to be slow,
notwithstanding acknowledged benefits to resource
conservation, while there are real and perceived financial
disincentives such as cost of machinery changeover as
well as uncertain benefits for their farmprod uction
system. Farmers are reluctant to commit additional
scarce funds to purchase new machinery suitable for
handling high stubble densities during the testing phase
of the practice on their farm. Farmers will only purchase
new equipment if the practice is found to be better than
what they are currently doing