New study researches foliar uptake

Limited information on leaf absorption of foliar applied liquid nitrogen fertiliser in wheat prompted University of WA (UWA) student, Gavin Carter to research this action as part of a fourth-year thesis for his agricultural science degree this year.

Gavin comes from a family farm near Kalannie where his parents, Steve and Leeanne, grow wheat, barley and canola and run Merino and crossbred sheep over 8100ha at their Xantippe Farms property.

The Carters were one of the first users of CSBP’s Flexi-N liquid nitrogen fertiliser for their cropping program in the region, with many farmers coming after them.

“There is not much information available on the foliar uptake of Flexi-N in wheat, so I took a look at this to get an idea of what is absorbed through the leaf, ” Mr Carter said.

“This can help farmers understand in drier periods, for example, that if they are putting on Flexi-N and it doesn’t rain for a while, their crops can still be getting a boost.”

Performed in glasshouse pots, Mr Carter used different rates and timing of application with the Flexi-N.

“It was also restricted from going on to the soil to ensure leaf uptake only was being measured in the plants, ” he said.

The biomass was sampled at one, four and eight days after application and was analysed.

“Nitrogen concentrations in the plants increased as the Flexi-N rate increased and over time the Nitrogen percentages decreased, which could be a factor of the growth response in the treatments resulting in a diluting effect.

“From the control treatment through to the highest rate of Flexi-N, which was the equivalent of 45 kilograms/ha of Nitrogen, there was a 0.5 per cent increase in total shoot Nitrogen concentrations, which was significant.”

Mr Carter said the visual growth response in the treatments was quite noticeable too.

“There was also noticeable leaf scorch at the high rates of Flexi-N, which is often observed, but there was no effect on the younger leaves.”