Mr English, who has the substance abuse problem?

(First published on The Farming Show July 2012)

At the recent Federated Farmers AGM, Bill English made an off the cuff joke about drug testing beneficiaries. It got some laughs and applause from the audience, no doubt happy to see the government picking on a group other than farmers for a change.

His comment got me thinking. If ever there was a substance that agriculture was addicted to, it’s phosphate. Unlike some of our other inputs, there’s simply nothing that can stand in for it. In the words of the U.S. Geological Survey “There are no substitutes for phosphorus in agriculture”. We currently import most of our phosphate fertiliser from Morocco.

Until recently, Moroccan phosphate seemed to be our only option for importing fertility (locally made urea is our primary source of supplementary nitrogen) but that looks set to change with recent offshore developments. Large deposits of rock phosphate exist on the Chatham Rise and extraction is being investigated now.

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Can we embrace the maths of sustainable farming?

(First published on The Farming Show June 2012)

A maths lesson might seem an odd way to start a column on sustainable farming, but bear with me for a second.

We’re all familiar with the idea of exponential growth: it’s the function that drives compound interest, economic growth and population size. Those hockey-stick graphs that shoot upwards ever steeper are just the exponential function on paper.

Any system that repeats percentage growth qualifies as exponential. It doesn’t stop for a breather: it’s a percentage increase year on year that uses the previous year’s total in its calculation for the next.

In farming and food production terms, we all know that we’ll face the global problem of infinite growth on a finite planet eventually, as we hit the ceiling of food production and input resources.

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