They say that it’s a bad day that you do not learn something and the same can be said about a bad year. It may well be a while again before we can benefit from any of the lessons learned in 2018, so it is important to document them for the record.

Just before harvest, a Wexford barley grower told me that he was very happy with a block of spring barley grown on lighter land that he had treated with N16 all season in an effort to keep it growing before the stress began to bite.

He did not treat one of the fields on a farm, which might be regarded as being a better field, so he could judge what was happening. The treated fields looked better all year.

Art Murphy grows a lot of malting barley and is no stranger to good spring barley yields. He does a very good job, with emphasis on getting the basics right, and understands the importance of keeping crops growing all the time. So seedbed and fertility are major priorities.

He told me that he had treated most of one rented farm with four applications of N16, plus one application of foliar potash, from the late tillering stage onwards to help offset possible moister stress.

The benefit of these foliar treatments was very visible to those who saw these fields. But I questioned how nitrogen alone could have this affect where availability of all nutrients was limited by moisture.

The answer to this lay in a conversation with Tom Breen, of Breen Agri Services in Wexford, who makes N16.

Multiple applications

Art had used N16 on four separate occasions during the growing season. He had decided early in 2018 that the year presented a real risk of dryness and stress following the prolonged bad weather.

So he was very much on the lookout for any signs of crops under stress or the early appearance of patchiness in fields. His objective was to try to keep the crops growing through this stress period in an effort to delay the evil day when moisture stress would really grip.

For me, applying nitrogen alone had the potential to further aggravate the stress if availability of other nutrients was also constrained by dryness.

This was particularly a concern for malting barley where additional N had the potential to increase protein and the risk of rejection, especially if it did not drive additional grain fill.

Tom agreed that this is a potential risk and that he would normally recommend a single application of 10l to 20l/ha of N16 – sometimes a grower would opt for a repeat application.

But Art decided, based on previous experience, to use four separate applications at 17.5l/ha. He also applied foliar potash late in the season. The results were better than one might expect, but Tom shed some light on the likely reasons for this.

The first reason Tom suggested was that Art was proactive towards the likely risk. Once the crop shows stress in patches, it is inevitable that yield potential is lost in these areas, as the crop will begin to thin out. Being there ahead of any symptoms helped to retain yield potential in the crops.

Tom also explained that N16 is not just nitrogen – that was very important. It also contains a small amount of P, plus magnesium and calcium. It even contains some molasses. So it is really a foliar feed used to help maintain the yield and quality potential of a crop.

The fact that N16, plus the foliar potash, supplied most major nutrients suggests that it has the potential to force new growth for a period. This may be enough to drive a burst of root growth into a new area of soil where it may then access a new pool of nutrients and moisture. But the real trick was in continuing the process when the drought got progressively worse.

Crops kept growing

The treated and untreated fields showed visible differences during the growing season and these were much more visible prior to harvest. The fields that got the extra treatments showed much fewer stressed patches and visibly better grain fill (see pictures above).

The treated crops seemed to run to maturity to give normal grain fill. The untreated field (this still got all other good husbandry inputs) had visibly poorer grain fill and the ears were still standing up at harvest due to lack of grain fill.

These crops are now harvested and the yields tell the tale. Art reported that the field that was not treated with N16 yielded 2.3t/ac with excess protein for malting and 15% screenings. Unfortunately, these were not totally untypical this year.

Yield in the treated fields was fractionally over 3t/ac, with insignificant screenings and only a few smaller grains blown out the back of the combine.

Protein levels in these fields averaged 12%, reflecting the better grain fill, despite the additional nitrogen. Straw yields were similarly affected, with big benefit from the application of the N16 treatments. The total amount of additional nitrogen applied was quite small at 3.5kg N/ha per application or 14kg N/ha in total. The yield kick was disproportionate.

Not definitive

It is important to state that this result cannot be regarded as an experiment, nor can it suggest that this is the only treatment that might give such an advantage. The N16 treatments were the only ones used, but there can be no doubt as to the benefits.

Tom emphasised that N16 is not a fix-all for all problems. It helps to prevent problems from developing and is best used as part of a programme. And that is exactly what Art Murphy had done.

He had anticipated problems and he decided, based on previous experience with N16, to apply it to help delay the evil day when moisture stress would kill the crop. The main objective is to try to prevent growth from stopping.

Tom said that it can be used to jump-start a crop, but it is better used to prevent the stop. It will not always deliver a dramatic yield benefit (depends on the season), but Tom emphasised that quality benefits are nearly always seen.

The nitrogen in N16 is in the amine form (NH2), which is what the plant actually uses, and this too is a help. But the presence of the other nutrients is also a big help.

Perhaps treatments, such as Wuxal Multiplant or other multinutrient combinations, could produce similar benefits. But if it is another 40 years before we get similar conditions, it may be of benefit to have this particular experience recorded.

Main points

  • The application of four treatments of N16 helped maintain yield potential and grain quality in spring barley.
  • In total, the four foliar N treatments applied an additional 14kg N/ha.
  • The treatment resulted in a significant improvement in both grain yield and quality.