Studies carried out by NSW Department of Primary Industries (DPI) show that where crop yield potential is high, wider row spacing can potentially reduce grain yield in winter cereal crops.

Studies carried out by NSW Department of Primary Industries (DPI) show that where crop yield potential is high, wider row spacing can potentially reduce grain yield in winter cereal crops.

NSW DPI researcher Dr Peter Martin presented the results of NSW DPI row spacing trials conducted in 2007 and 2008 at a range of sites in central and southern NSW, at the recent Grains Research and Development Corporation updates at Wagga Wagga.

The data presented came from trials run by Peter Martin, Jan Edwards, Barry Haskins and John Smith. Comparative data came from previously published scientific reports.

After comparing trial results with similar trials to see if there were any trends that farmers and advisers should be aware of, Dr Martin concluded that where crop yield potential was high (>3 t/ha), wider row spacing could potentially reduce grain yield in wheat.

He found that where yield potential was lower (<3 t/ha), there was likely to be no effect of wider row spacing on grain yield.

Dr Martin said there appeared to be no yield penalty for grain legumes or canola when row space is increased up to around 36cm.

He said traditionally, winter crops have been sown using an 18cm (7 inch) row spacing.

"In recent years, there has been increased interest and adoption of wider row spacing with row widths ranging from 23cm to 35cm and even some at 45cm.

"The use of no-till and stubble retention systems has to large part driven much of the interest in wider rows.

"Gains in stubble handling ability, faster sowing speeds, lower machinery costs and the potential to inter-row sow are just some of the reasons cited for adoption.

"However, wider rows can result in slower canopy closure, seed germination issues resulting from increased concentration of fertilizer and higher populations in the row, and reduced competitiveness against weeds.

"They could also potentially impact negatively on grain yield," Dr Martin said.

NSW DPI Agronomist based at Wagga Wagga, Nigel Phillips, said if wider rows were implemented then a clearly thought out weed management strategy was required, which may include changes in herbicides and rates.

"The effects of row spacing on soil evaporation losses are mixed, and therefore producers should be careful about using soil moisture management as a basis for changing row spacing," he said.

"In agriculture there are always pros and cons to every farm management option. Row spacing is no exception. Producers should look carefully at the evidence and the economics of various row space configurations before making a balanced decision that suits their particular farming enterprise."

Contact: Sarah Chester on (02) 6036 2110 or 0417 207 669

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