Growers urged to count the yield cost of wide rows
Author: Sarah Jeffrey | Date: 07 Jul 2014
Winter cereal growers in the northern region are being urged to carefully assess the yield cost of their row spacing decisions.
Research suggests that in some cases the cost could be significant, particularly in areas where high crop yields are possible.
Grains Research and Development Corporation (GRDC) supported trials by NSW DPI researchers at the Tamworth Agricultural Institute and the Condobolin Agricultural Research & Advisory Station in 2009 and 2010 found that yield loss from 30 cm to 40 cm row spacings averaged approximately 0.3 tonnes/hectare but varied from less than 0.2 up to 0.8 t/ha.
However yield losses were more consistent and much greater at 50 cm row spacing with nearly a 1.0 t/ha yield reduction compared to the 30 cm row spacing.
NSW Department of Primary Industries Northern Cropping Systems Manager at the Tamworth Agricultural Institute Dr Guy McMullen said recent results from southern Australian trials supported the northern data and urged growers to consider their row spacing decisions both from a yield perspective as well as within the context of the wider farming system.
Trial work has consistently demonstrated that crops sown in wide rows are less competitive with weeds, costing yield and enabling weed survivors to set seed and propogate.
“This is leading us to question whether we can afford to continue with wide row spacings in winter crops to manage stubble,” Dr McMullen said.
“Wider rows not only cost yield, they lose competitive advantage against weeds and impact on growers’ bottom lines.
“With the increasing prevalence of herbicide resistance, any gain in controlling weeds in a crop is a gain well worth capturing and the yield benefits can be significant.
“In the two trial locations, Coonamble and Spring Ridge, in 2009 there was between $6 and $16/ha loss per centimetre increase in row spacing.”
It is well recognised that stubble cover plays a key role in conservation farming practices by maximising water capture, infiltration and storage, and the adoption of wider row spacing has enabled growers to sow into higher levels of retrained stubble.
Additionally, wider row spacing has the capacity to reduce fuel costs during sowing and/or increase sowing speed, allow for inter-row sowing of subsequent crops, reduce soil disturbance and lower the cost of sowing equipment.
“Unfortunately bush myth has also added the concept that wider rows also assist yield stability in drier seasons,” Dr McMullen said.
“However in the range up to 50 cm there is no compelling data to support this with winter crops.
“It’s only when you move to very wide row configurations such as single and double skip rows in summer crops with different root systems, where inter-row areas are very wide that such effects occur.”
Dr Guy McMullen, Northern Cropping Systems Manager
NSW DPI, Tamworth Agricultural Institute
02 6763 1155, 0428 256 544
Sarah Jeffrey, Senior Consultant Cox Inall Communications
0418 152 859
GRDC Project Code VSAP DAN00176
GRDC Project code: VSAP DAN00176
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