The impact of row direction has been examined in combination with row spacing and population for the first time to maximise yields in the prime sorghum-growing region of NSW’s Liverpool Plains.
The NSW Department of Primary Industries (NSW DPI) research with GRDC support shows when water is not limiting; crop orientation and plant spacing have little impact on crop yield potential.
Dr Guy McMullen and Loretta Serafin, NSW DPI, Tamworth undertook the research in 2007 and 2008 and presented their findings at the recent GRDC Updates. Ms Serafin is also a current member of the GRDC northern panel.
The 2007/8 season was one of the highest yielding sorghum seasons on record in northern NSW due to a combination of mild summer temperatures and above average rainfall.
“Under these essentially non-water limited conditions there were no significant differences between row direction or row spacing at both trial locations and the only population response was at the Somerton site at 37,000 plants per hectare, resulting in a lower grain yield,” Ms Serafin said.
“While additional yield has been recorded with north/south configurations in winter cereals in the absence of weed competition – mostly attributed to additional sunlight on the plants down the row and less shading – orientation responses were not detected in sorghum in this study.”
Previous research supports the conclusion that row orientation in sorghum did not significantly affect water use or yield.
“Although plant population treatments differed markedly in plant, tiller and head density it appears that the crop was able to compensate through increased grain numbers as there was no difference in the grain size between any of the treatments at the Premer site,” Ms Serafin said.
“Narrow row spacings failed to provide any yield benefit over wider row spacings under high yielding conditions.
“It may be possible that under favourable growing conditions in which water is essentially non-limiting, other factors such as crop nutrition may be the most limiting factor to grain yield.”
MR Buster, the hybrid used in both trials, is noted for its ability to increase tiller numbers under favourable conditions.
Ms Serafin said there had been considerable interest in the northern cropping zone in sorghum traits such as Staygreen and low tillering growth habits.
“The capacity of hybrids with these traits to capture maximum yield in favourable seasons needs to be investigated fully,” she said.
For more information, visit www.grdc.com.au
