Split application of nitrogen can reduce biomass but maintain yield in maize in northern NSW

Loretta Serafin1, Mark Hellyer1 and Neroli Graham1

1 NSW Department of Primary Industries, 4 Marsden Park Road, Calala, NSW 2340. www.dpi.nsw.gov.au, loretta.serafin@dpi.nsw.gov.au  


Four field experiments were conducted in the 2014-15 and 2015-16 seasons to compare interactions among nitrogen rates, application timing and maize hybrids. Two experiments were conducted at Gurley, south of Moree, under rain-fed conditions and two were conducted at Breeza, on the Liverpool Plains, under irrigated conditions. Nine nitrogen treatments were imposed in each experiment with seven treatment rates, ranging from 0 to 250 kg N/ha applied upfront at sowing, and two split treatments of 75:75 and 100:100 kg N/ha with half applied at sowing and half at the 6-8 leaf growth stage. Two medium maturity maize hybrids, Pac606 and Pioneer 1467 were selected for comparison.  Biomass production was highest from the 100 kg N/ha and 75:75 split treatments in both hybrids, and the 150 kg N/ha treatment in Pac606. The lowest plant biomass was obtained from the 250 kg N/ha and 100:100 split treatment in both hybrids.

A positive linear yield response to N application was seen in both Pac606 and Pioneer 1467 with the highest yield obtained with the application of 250 kg N/ha. The 100:100 split application treatment reduced plant biomass when compared to 200 kg N/ha applied upfront but achieved similar yields. Kernel number had a strong correlation with grain yield but there was either no correlation or a weak association between plant biomass and grain yield with each of the hybrids. These results suggest splitting N application with 100 kg N/ha applied at sowing and 100 kg N/ha applied at the 6-8 leaf growth stage could be an appropriate strategy to maximise water use efficiency of maize under both rain-fed and irrigated production systems in northern NSW.



The Australian Society of Agronomy is the professional body for agronomists in Australia. It has approximately 500 active members drawn from government, universities, research organisations and the private sector.

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David Marland Photography david_marland@hotmail.com Southern Farming Systems Agriculture Victoria

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