South Perth, Western Australia
February 26, 2004
Lower yields
and higher screenings in wheat have been linked with wide row
spacing but can be managed according to latest research by the
Western Australia
Department of Agriculture.
Speaking to growers at the Crop Updates in
Narrogin yesterday, researcher Mohammad Amjad said the
Department had developed a number of key agronomy options based
on research over a three-year period at Salmon Gums.
The Crop Updates seminars are supported by the
Department of Agriculture and the Grains Research and
Development Corporation.
Dr Amjad said the desirability of increasing row
spacing to assist stubble management and plant population for
better competition against weeds, needed to be balanced against
the potential for reduced yield and increased small grain
screenings particularly in drier years.
“The Department conducted investigations on wide
rows in 2000, 2001 and 2002 on an alkaline, grey sandy duplex
soil using the long season variety Camm, mid-season variety
Cascades and a short season variety Westonia,” Dr Amjad said.
“The research found that narrow row spacing (180
mm) consistently resulted in higher yield, lower protein and
lower small grain screenings over three years at Salmon Gums.
Increasing the row spacing increased the grain protein and
screenings. “
Dr Amjad said yield reduction in wider rows could
be related to the high concentration of seed and fertiliser in a
narrow band causing fertiliser toxicity and resulting in reduced
plant germination, reduced competition with weeds and ultimately
more small grain screenings and less yield.
He said wider row spacings also generally changed
grain size distribution with more small grain and less large
grain in harvest grain samples during 2000.
“However, the research demonstrated that yield
reduction at wide row spacing (360 mm) could be managed by
increasing the row width (spread) up to 75 mm and was less
significant in Camm - the long season variety,” Dr Amjad said.
“If the lower impact of wide rows on Camm also
applies to other long season varieties, this could be used to
reduce the negative impact on grain yield.
“A greater spread of seed within the row will
also assist competition of the wheat crop with weeds.”
Dr Amjad said the research provided six agronomic
management options that could be adopted both in existing and
new farming systems for improving grain yield and quality on
wide rows.
-
Select slow maturing, longer
season wheat varieties.
-
Maintain the target plant
population at 150 plants/m2.
-
Increase nitrogen rate for long
season wheat varieties.
-
Early sowing (May) improves
yield and weed competition in wide rows.
-
Deep place fertiliser away from
seed.
-
Increase the lateral spread of
seed within the rows to 50 to 75 mm.
“New technological developments in farming
systems including ribbon seeding, paired rows, separate
placement of fertiliser from seed, controlled traffic, deep
ripping, liquid fertiliser and herbicide application, may also
help to improve operational efficiency and reduce costs at wider
row spacings,” Dr Amjad said.
“This research has demonstrated how to manage
yield reduction at wide rows,
and farmers can now fully consider both the pros
and cons of wider row spacing in their farming environment.”
The research was undertaken by the Department of
Agriculture and the South East Premium Wheatgrowers Association,
with funding from the Grains
Research and Development Corporation. |