Effect of row spacing on sorghum yields
From the October 2008 edition of Agriculture Today.
A NSW Department of Primary Industries (DPI) trial has shown that skip row configurations in sorghum are unlikely to give a yield benefit in easterly areas such as the Liverpool Plains when sowing into good moisture.
DPI district agronomist at Gunnedah, Bill Manning, said the trial, which took place in the 2005-06 summer crop season, supported previous research.
"The use of skip rows in sorghum production can assist by saving water for grain fill and by delaying the onset of moisture stress," he said.
"Sorghum roots grow at a rate of approximately 2.5 centimetres a day.
"Research and modelling has generally indicated that based on a one metre row, skip rows will only give a yield advantage where starting soil water is low, or in marginal areas where in-crop rainfall is less likely."
Mr Manning said skip rows also had the effect of reducing top-end yield potential in good years.
DPI planted seven row spacing trials at Coonamble, Garah, Gurley, Pine Ridge, Premer and Winton using the variety MR Buster.
The aim of the trials was to revisit the effect of row spacing on sorghum yields across a number of environments.
Trials were established on sites with good starting moisture profiles at 45,000 plants per hectare regardless of row spacing.
Trials were sown from late October to mid November, seasonal conditions varied from site to site but were characterised by very hot conditions in January, (see graph).
Mr Manning said a yield benefit from skip rows was only gained at two sites where difficult seasons were experienced.
"This work did not measure potential benefits of skip rows on limited moisture profiles or the benefits of extra moisture left behind after skip row crops," he said.
Contact Bill Manning, Gunnedah, (02) 67 41 8366, william.manning@dpi.nsw.gov.au or Nathan Ferguson, Tumut, (02) 6947 4188, nathan.ferguson@dpi.nsw.gov.au
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