Fertiliser rivals bicker over research

The effectiveness of nitrification inhibitors has brought about a spat between two big fertiliser companies.

The dispute has been sparked by fertiliser company Ballance Agri-Nutrient's research into the effectiveness of dicyandiamide (DCD) - the active ingredient in products designed to reduce nitrate leaching - sold by it and Ravensdown Fertiliser.

Nitrate leaching can occur from mineralisation in soil, cattle urine patches and fertiliser.

The argument centres around the effectiveness of DCD in reducing leaching, retaining nutrients in the soil and improving pasture production.

Warwick Catto, head of agro-sciences at Ballance, commissioned AgResearch to carry out research on brown soil in Southland, pumice soil in Bay of Plenty, volcanic soil in Waikato and clay soil in Northland.

Tests of liquid and solid formulations showed the two methods were equally effective at inhibiting nitrification and on pasture production.

The study showed nitrate leaching was reduced by 20 to 30 per cent depending on soil type, nitrous oxide emissions were reduced by 75 per cent and pasture production increased by about 5 per cent.

"The key conclusion that can be drawn from this research is that DCD inhibits the nitrification process, resulting in a reduction in nitrate leaching and nitrous oxide loss," Catto said.

However, the results were short-term reductions and "for the whole farm system longer-term impacts are likely to be less substantial.

"Having retained the nutrients on the farm through DCD use, we now need to assist farmers to get value out of them."

Reduced emissions of greenhouse gas nitrous oxide would have a positive impact on the environment but Ballance corporate communications manager Peter Mourits said economics would determine sales.

"The key benefit that they [farmers] would be looking for is additional pasture growth."

Research showed production increased by about 5 per cent, or up to 10 per cent in urine patches, on Waikato and Bay of Plenty soils but did not increase in Southland and Northland.

However, Ravensdown Fertiliser's strategic development general manager, Richard Christie, said his company's research on different soil types consistently showed leaching reduced by 60 per cent and production increased between 10 and 15 per cent.

"Our orders are now triple what they were last year ... and these farmers, the only thing they look at is pasture production. So here you have the results speaking for themselves."

Christie said Ravensdown wanted to distance its product from the Ballance study.

Ravensdown's fine particle spray was launched last February and the granule-based Ballance product was launched last March.