Under the heading ‘Evaluating the agronomic effectiveness of fertiliser products’, authors Doug Edmeades and Richard McBride, of agknowledge, conclude there’s a better way to present product research results. In reaching that conclusion they’ve analysed trial work behind a string of plant growth-enhancing products marketed in New Zealand, and a couple widely used overseas but yet to be launched here.
For some products the authors’ findings support the marketing claims, but for others their analysis is damning: “…this product has been shown to be no better than water,” they write in one instance.
Edmeades says the problem is selective use of data, or trials, and statistical analyses which make it impossible to tell if the product is having no effect, or the trial is simply not powerful enough to detect the effect. “This problem can be objectively and pragmatically solved, when sufficient trial data are available, by using cumulative frequency distribution functions... this approach provides a more objective basis for determining the efficacy or otherwise of fertilisers,” the authors write.
Edmeades admitted to Rural News that even this approach is open to abuse but, if all data is included, the reader can easily see the full range of results that a treatment or product achieves.
They should also look for evidence that the presentation of the data has been peer reviewed by the scientific community. If it hasn’t, that should raise questions. Too often in recent years, such data hasn’t been available, even for some relatively mainstream products offered by large companies with the resources to fund such work.
“There are three widely promoted ‘new age’ fertiliser products on the market without proper, independent peer-reviewed science behind them,” he warns. From purely commercial companies that’s bad enough, but the fact some examples come from farmers’ own firms – the cooperatives – is even worse. “Until the farmers wise up and demand their cooperatives behave better, nothing will change.”
This situation can be attributed to the Crown Research Act and abolition of MAF’s research division, which was responsible for testing products peddled to farmers. “Under the CRI Act the CRIs don’t have that responsibility. It’s a problem of science policy as much as anything else. There’s no one looking after the farmers’ interests.”
Occasional pieces of levy body-funded work shed some independent scientific light, but those are few and far between, either because funds are in short supply or for political reasons.
“Funding such work is a major, major problem. It’s why the [NZGA Conference] organisers this year have asked for papers testing products.... The science must be asserted against the odds and against the legal threats.”
