Independent agronomist and AICC chairman Sean Sparling says very few of his clients still use urea.
“For those that do, I strongly recommend that it is only used as a first application early in the season to provide 50 – 60kg/ha N when it is cold enough for volatilisation not to be a problem.’
Lower cost is usually the advantage given by users, but even that needs re-examining, he says.
“People tell you urea is lower cost because it is 46%N as opposed to 34.5%N for AN, but in recent years there has been very little difference in true costs yet you don’t get all the risks associated with urea when you use AN.
“Plus because AN is denser you can spread it to wider widths with conventional lower cost equipment whereas you really need a pneumatic spreader to use urea safely at the same widths.”
But the biggest advantage with AN is simply its consistency and reliability, he says.
“You put it on and within 48 hours it is taken up by the plant. Knowing what you apply is being fully used by the plant without a proportion lost to the air is better for the crop, the bank balance and the environment.
“When we’re all being encouraged to use inputs more carefully and use a more precise approach to growing crops generally, that’s important. I think there are just too many variables to be comfortable with urea now.
'Whilst there can be problems with any fertiliser type if incorrectly managed or applied, issues with AN are far easier to manage than those with urea.”