During his recent travel to Europe, Dr Bert Quin visited research institutes, in Spain and northern Ireland and the Irish Rebublic where research is being conducted into various aspects of use of the urease inhibitor nbpt. This inhibitor has a very simple role; it slows down or ‘inhibits’ the conversion of fertiliser N (or urine N when used with Spikey®) for just a few days before decomposing itself into plant-available forms of N and P. The enormous benefit this provides is much, much lower ammonia volatilisation, as the peak concentrations of ammonium in the soil are reduced. Also, the more extended conversion of urea to ammonium automatically means slower conversion to nitrate-N, meaning better uptake of N and therefore better pasture response. The science is as obvious as the results; more than 50% of Ballance clients now use SustaiN (nbpt-coated granular urea), a product Dr Quin developed and introduced through Summit-Quinphos in 2002. Dr Quin said that despite some disappointment over the industry’s initial criticism of the product, it is very satisfying to see that the benefits of the product are now recognised. On average, it improves urea efficiency by 25-30%.
“One of the great things about nbpt is the absence of residue problems, because of the rapid decomposition of the product of 10-20 days” said Dr Quin. “ Research in Spain has shown that it is completely safe even when sprayed on to vegetables such as lettuce. It has been shown to prevent excess nitrate levels occurring in vegetables. No residues could be detected after 20 days”. It is highly likely that it has the same benefit in preventing excessive nitrate levels in ryegrass, according to Dr Quin.
The new nbpt-spray treated prilled urea known as ONEsystem®, recently developed by Dr Quin with private funding from Global Sustainable Farming Ltd (GSF), takes urea efficiency a lot further ahead again – by 170 to 290% depending on conditions. “At these efficiencies, we are seeing the great majority of the urea being recovered by the plant, which is the way it should be” he says. Another advantage of ONEsystem® is that, by being designed to be used on a ‘follow-the-cows’ basis on dairy farms, a whole new level of residue protection is built in, as the cows do not return for to a given paddock for 20-30 days. “I truly believe that ONEsystem® will revolutionise fertiliser N use in New Zealand” says Dr Quin. SustaiN was a good first step in the right direction, but ONEsystem® is the end-game, he said. Results of independently conducted trials under grazing are being presented to the NZ Grassland Society conference in Masterton in the first week of November.
However, Dr Quin recommended real caution regarding the introduction of products containing untested alternative urease or nitrification inhibitors in combination with the tried and tested nbpt. Companies that release such products may be doing so deliberately to sow doubts in the dairy industry, and are playing fast and loose with NZ’s reputation. “Their arrogance is beyond belief” said Dr Quin.