NDDT and Dairy NZ reject Summit-Quinphos claims

NDDT and Dairy NZ reject Summit-Quinphos claims

The Northland Dairy Development Trust (NDDT) and DairyNZ are rejecting claims by Summit-Quinphos that recent NDDT trial work supports the effectiveness of its SustaiN fertiliser.

Last week [18th June] Summit-Quinphos issued a news release claiming that a trial conducted by the NDDT last spring shows greater dry matter yield responses to agrotain-treated urea compared to ordinary urea. Agrotain-treated urea is marketed by Summit-Quinphos as SustaiN. This trial was funded by NDDT and carried out and reviewed by DairyNZ staff.

NDDT trustee Kim Robinson and DairyNZ Strategy and Investment Leader Bruce Thorrold agree that the trial showed no statistically significant response to agrotain-treated urea compared to conventional urea.

“We don’t agree with Summit-Quinphos’s interpretation of the data – there was no statistically significant difference between N fertilisers in the trial. Over two applications of 40kgN/ha each the difference between standard urea and the average of agrotain+urea treatments was only 50 kg DM out of total response to N of 1400 kg DMᾬ saidᾠMs Robinson.

“Even the best performed agrotain+urea treatment produced only an extra 240 kg DM in response to the two applications.”

“Many trials have been carried out in New Zealand with agrotain treated urea with a wide range in responses measured. The responses in the NDDT trial were small and non-significant,” said Dr Thorrold.

“While scientists have put forward a range of explanations for the variability, the proven explanations don’t explain the range in responses seen. The NDDT trial supports the principle that it is the amount of N applied that has the greatest effect on pasture yield. So unless further research proves otherwise, it is my opinion thaῴ farmers should generally use the N fertiliser that has the lowest cost per kg N applied, he said.

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