Challenge claims, farmers told

In his final address as Federated Farmers' dairy chairman, Kaharoa's Lachlan McKenzie called on farmers to be more proactive in correcting industry misconceptions.
McKenzie pointed to trout, nitrogen and water quality as examples of areas where farmers needed to ask more questions and, once they had the answers, to be more vocal in getting the truth out to the public.
"I have given you just three examples where opinion is not supported by the facts, yet assumed causes and assumed links are actively driving policy."
Giving the opening address at Federated Farmers' annual conference in Rotorua yesterday, McKenzie said the industry needed to question "truths" - scientific and economic - before making responses as its reticence had been to its disadvantage.
"These things need debating."
He said the dairy industry was bearing the brunt of allegations that milk prices were too high but, in relative terms, milk had been more expensive in the past.
"We have to ensure the facts are understood and communicated. The truth is the truth and it will, eventually, be understood, but it needs to be championed by you."
McKenzie gave examples from his own experience with the Land and Water Forum, describing trout as "the stoats of New Zealand's waterways", arguing against the commonly held view that the water quality here was declining and claiming phosphate levels were more of a problem than the more prominent nitrate issues.
"Of the 50 most invasive fish species, rainbow trout rated 26th and brown trout at 47th. We have to look at trout in a whole new light."
He quoted research figures showing algae growth was up to six times higher in streams with trout, because they ate the invertebrates that fed on the algae and kept it in check, but he said the non-native fish were protected by legislation and were even bred on Department of Conservation land in the Bay of Plenty.
"Native fish struggle. Without trout, algal growth is kept in check and our streams and aquatic biodiversity achieves balance."
Algae populations are also limited by the nutrients in the water and McKenzie said, despite the strong focus on nitrogen levels, phosphorus was the determining factor for algal growth in 76 per cent of the 1100 freshwater streams monitored by councils.
"Any call by government and councils to control nitrogen is based on less than 24 per cent of the situation."
He blamed wastewater full of shampoos and detergents for many water quality problems and said farmers and nitrate leaching were scapegoats. "We should be coming at this from aquatic biodiversity, but it is much easier to blame farmers. Farming does affect water quality, but it is being attributed 100 per cent of the blame."
However, he said the assumption New Zealand's water quality was declining was untrue, with periphyton algal-bacterial cover decreasing in more places than it was increasing.
"We've let claims go unchallenged and, in the minds of some members of the public, the lack of challenge means those claims must be true."