With increasing crop demand for nitrogen (N) fertiliser, what are the opportunities for increasing the efficiency of what we apply to cereals?

Are there efficiency gains from banding N at seeding compared to post seeding boom applications, and can banding N at the start of stem elongation give better results than streaming it onto the crop?

The advantages of banding N are mainly related to reduced potential for immobilisation losses, and to a lesser extent volatilisation – the risk of volatilisation being greater with urea.

On the other hand, N applied at seeding is more susceptible to leaching – in a leaching environment.

A trial on Scepter wheat at South Stirlings last year sought to compare the effectiveness of banding Flexi-N at seeding to streaming it on early post seeding, with another comparison of these methods at early stem elongation.

While the site was moderately (and profitably) responsive to N (with 151 kg N/ha lifting yields from 2.7 to 4.6 t/ha), there were no clear effects relating to either N placement of timing.

Compared to streaming Flexi-N, there was no agronomic benefit from banding N at seeding or at early stem elongation.

Why?

Most likely because there wasn’t enough stubble residue to tie up the N applied to the surface.

Compared to delaying the first application until the three leaf stage, banding Flexi-N at seeding was just as effective.

Why?

Conditions post seeding were relatively dry, so there was no risk of early leaching losses.

The benefits from banding Flexi-N are greatest where there are high stubble residues, and broadcast applications are uneven, or unavailable because they are not washed into the root zone.

Sure, banding N at seeding may be at susceptible to leaching, but that will only be in a leaching environment.

The risk of leaching losses needs to be weighed up against the risk of immobilisation losses and of course the logistics of any need to applying N over the season – particularly if high rates are required.

James Easton
By James Easton
- Senior Agronomist

James has over 30 years’ experience working on soil and plant nutrition (crops and pastures).

He graduated from the University of Western Australia with a degree in Agricultural Science (Honours). He has in depth knowledge of historic fertiliser research trials and has worked closely with many growers, consultants, research institutions and farming groups over the years.

James gets a lot of satisfaction from sharing his knowledge with growers and those who support them. And he enjoys the fact that we are always learning.

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