Friday, March 29, 2024

Promise of fertiliser efficiency improvement

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Dr Bert Quin, former chief scientist for soil fertility at Ruakura and founder of Summit-Quinphos, hasn’t been letting the grass grow under his feet since retiring 10 years ago. 
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Quin and his development partner Pastoral Robotics, headed by Geoff Bates, are excited about the potential that their Spikey urine detection and treatment has for minimising nitrate leaching on dairy farms, and covering the cost by turning the nitrate into increased grass growth (Dairy Exporter, June 2015, p78).

Quin says improving the efficiency of fertiliser urea is just as important as reducing urine-nitrogen losses. 

“This has become increasingly important with the rapidly increasing use of urea on dairy farms, and even more so with the recent large decline in dairy farmer incomes,” he says. 

SustaiN (granular urea coated with nbpt) was developed by Quin and introduced by Summit-Quinphos in 2002. 

“The product was a good step in the right direction, with an average improvement in efficiency of 25-30% per kg nitrogen over normal granular urea, but I always knew I could find much bigger improvements given the time and opportunity,” Quin says.

Since getting funding for his research 18 months ago, Quin has worked to bring his ideas to reality. The result is ONEsystem, a patented technology that uses prilled urea (average granule size 1.5 mm) instead of traditional granular urea (5mm). During spreading, the prills are wetted with a low-rate (50l/ha) water spray containing the urease inhibitor nbpt. 

“A number of different factors combine beautifully to give the level of efficiency I had been looking for; on average twice as efficient as granular urea. When you combine that with a similar price per kg nitrogen, it is truly exciting.” 

The ONE in ONEsystem stands for Optimised Nitrogen Efficiency.

Quin says it has been known for decades that granular urea is very inefficient when surface-applied. 

“Theoretically, urea should produce about 30kg extra drymatter (EDM) per kg of nitrogen applied (an EDM factor
of 30). It was almost invariably much less than this. The default EDM factor used by most farm advisers is 10; it can be as low as 2 or 3 in autumn”, he says. 

“Like nitrate leaching from cow urine, this is a serious waste of farmers’ money.” 

The development of ONEsystem involved looking at the individual nitrogen-loss mechanisms from granular urea applied to pasture, and seeing what could be done about it cost-effectively. 

Quin says ammonia volatilisation is just one of several serious loss mechanisms. 

“Nitrate leaching and nitrous oxide emissions are also important,” he says. 

Pasture response has been measured in trials run by independent scientist Dr Allan Gillingham and field technician Maurice Gray in Southland, Canterbury and Waikato. Quin says the biggest improvements have been achieved in Canterbury. 

“It was far more costly to do the trials under grazing than just doing small-plot trials, but it was necessary if we were going to find the responses that farmers would get in real life.” 

Preliminary results were presented at Massey University’s FLRC conference in February, and autumn trials have recently ended. 

Quin is staking his reputation on the effectiveness and environmental benefits of ONEsystem. 

“Using prills instead of granules is an important component of the improvement. When you count them, you have about 10 times as many particles in any given area with prills as with granules. For example, at 30kg nitrogen/ha you get only 45 granules per square metre, whereas prills give you 450. In a typical dairy pasture containing over 400 plants per square metre, there is simply no way with granular urea that all plants get the nitrogen they need; many miss out altogether while some get overdosed. Wetting the prills is also very important; this allows them to adhere to the leaves, promoting foliar uptake and rapid recovery by the roots, which minimises nitrate leaching. The nbpt minimises ammonia volatilisation losses.”

ONEsystem is now undergoing whole-farm testing through the recently formed company Global Sustainable Farming (GSF). It is hoped to start limited sales to farmers through selected spreading contractors this spring. 

“Farmers will be able to greatly reduce – by half in many cases – the amount of nitrogen they need to apply to maintain or increase production. The impact of this on inputs into Overseer will be very significant, as well as representing a big cost saving.” Quin says. 

“If the nitrogen fertiliser is up to the job, growing more grass will always be the cheapest way to produce milk.”

For more information and trial data go to www.groupone.co.nz/onesystem 

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