Friday, 10 May 2019 09:56

Snake oil or real information?

Written by  Dr Jacqueline Rowarth
Jacqueline Rowarth. Jacqueline Rowarth.

Dr Jacqueline Rowarth explains what farmers can look out for when figuring out if a product is snake oil.

In the current era, when farming seems to be at or near the top of the hit list for complaints from many different groups, it isn’t surprising that people are looking for ‘a better way’.

The people are from farming, support industries and society. All are open to persuasion by clever marketers, leveraging on a desire – in this case to do a better job. (It could equally well be ‘just three minutes a day to lose weight and get fit using the miracle machine…’)

This leaves them open to snake oil because desperate people will believe things that in normal times they wouldn’t entertain.

The boundary between clever marketing and snake oil is not hard and fast, but there are things to look out for that will give clues. 

Firstly, is the merchant credible? Does he or she have qualifications and a track record of professional experience? Is the track record appropriate for New Zealand? 

The soils and farming systems here are very different from those in the rest of the world. Our cows are pasture not grain fed and most of the productive land is under pasture not cropping. This is sometimes forgotten by groups such as Greenpeace when they advocate the replacement of animals by protein crops. NZ cannot yet produce commercially viable yields of soybeans, lentils or chickpeas. Most of NZ is unsuitable for cropping. 

Under pasture, NZ soils have relatively high organic matter, giving water holding capacity, aggregate stability and a nutrient reserve for plant and microbial growth. This is well known by soil scientists. Increasing organic matter even more is not as easy as when the starting point is low. Does the salesperson understand the issues?

Secondly, are the claims being made about the new way or new product supported with evidence? ‘Client testimonials’ are not evidence. Evidence is facts, data and research, preferably where appropriate comparisons have been made with other products or systems, and in a setting appropriate for NZ, by an independent science organisation? Time is a component – not a one-off trial.

Thirdly, are actual figures of production given – not percentages with no base starting point? A current example circulating at field days is that northern hemisphere farmers have cut their fertiliser use by 40-50% with no impact on yield. An obvious question is ‘yield of what’. Another is ‘what is the actual yield’? 

Actual could be before or after the reduction, but without a starting or end point the percentage means nothing. The same applies to the amount of fertiliser. Of note is that NZ’s nutrient balance, whether nitrogen or phosphorus, is lower (indicating greater efficiency) than many other countries can achieve. The OECD figures for 2016 (latest data) report that the Netherlands loses 99kg/ha nitrogen, UK loses 87 and New Zealand loses 59.5. 

Relativities are important. NZ is using more fertiliser than it did in the past, but not as much as other countries are using. Productivity (yield per unit of input) has increased hugely, which could be taken to indicate that insufficient fertiliser was being applied in the past. Increased productivity benefits the whole country, and onfarm this means being able to afford new technologies allowing precision application of water and fertilisers, for instance. 

Fourthly, what are the concerns that are being overcome with the new product or system? The suggestion has been made that NZ doesn’t need nitrogen fertiliser because clover can do the job. This overlooks the effect of clover root weevil, poor temperatures and the natural clover cycle within a pasture that operates on a 3-4 or even 7-8 year boom and bust dynamic. It also overlooks the fact that nitrogen is leached from a clover pasture. 

Research at Ruakura in the 1990s compared clover-ryegrass with ryegrass supplied with the same amount of nitrogen as the clover was fixing. The nitrate leaching loss was the same.

Clever marketers are everywhere and it is up to the buyer to beware. A bit of research on the web, and some simple questions, will help sort fact from fiction.

• Dr Jacqueline Rowarth CNZM CRSNZ HFNZIAHS is a soil scientist. Her research has focussed on phosphorus, nitrogen and carbon cycling. 


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