Australia
March 25, 2009
Source:
GRDC's The Crop Doctor
Forty years of crop sequencing
trials have recently been collated by the Department of
Agriculture and Food WA (DAFWA), giving Western Australian grain
growers real insights into the rotational benefits of break
crops.
Representing more than 160 crop sequence experiments, the
results were presented by DAFWA’s Mark Seymour at the
Grains Research and Development
Corporation (GRDC) supported 2009 WA Agribusiness Crop
Updates.
Mr Seymour said the database not only revealed the benefits of
break crops, but also shed light on the impact of changes to
crop management over the years.
The data clearly demonstrates that continuous wheat was rarely
as productive or economically viable as rotations that included
either a pasture or break crop, regardless of how much nitrogen
fertiliser was applied.
It also points to the difficulty of achieving yields higher than
2.5t/ha when wheat is sown after wheat. Overall, wheat sown
after lupin out yielded wheat sown after wheat.
Since 1990 both the yield of wheat on wheat and the likelihood
of a response to lupin in the following year have increased at
all levels of applied nitrogen.
This corresponds with an era of more effective herbicide use and
rotations that have shifted to more continuous cropping. Trials
in this era were more likely to be sown with no-till machinery.
Narrow leafed lupin has been the most widely examined break crop
species.
According to Mr Seymour, a lupin crop frequently provides a
break from Take-all, which severely limits wheat yields, or from
high levels of annual ryegrass or brome grass. Other crops, such
as field peas or canola, can also provide that essential break.
A detailed report summarising some of this extensive database is
being prepared as part of the GRDC’s project “Increasing the
Profitability of Cropping Systems in Western Australia using
Lupins, Oats, Oilseeds and Pulses.”
The Crop Doctor is GRDC Managing Director, Peter Reading |
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The Crop Doctor is
GRDC Managing Director,
Peter Reading |
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