Comment: When it comes to synthetic nitrogen fertiliser, good management practices should be encouraged, not an outright ban, writes Federated Farmers Climate Change and Trade Policy adviser, Macaulay Jones.
Synthetic nitrogen fertiliser is suffering from a PR problem in New Zealand.
It's regularly demonised and blamed for the degradation of waterways, for contributing to climate change and for enabling a perceived unsustainable growth of farming. Some are even calling for it to be banned altogether.
But while synthetic nitrogen fertiliser can undoubtedly lead to environmental issues if used carelessly, it's this careless use which should be avoided - not the use of the product.
A better approach would be to encourage good management practices by farmers; practices such as using the right amount of fertiliser, in the right place at the right time.
In contrast, a blanket ban would erase one of the greatest scientific and humanitarian breakthroughs of the twentieth century and would dangerously directly threaten the food security of half the global population.
At its most fundamental level, modern farming is about a smaller number of people growing surplus amounts of plants, so the rest of society can eat and pursue other activities.
Whether these plants are consumed by people directly, or fed to animals which are then consumed by people, one cannot farm without growing plants.
Along with sunlight and water, plants require nutrients to grow. The three main nutrients demanded by plants are nitrogen, phosphorus and potassium, with nitrogen often being the input constraining growth, and whose addition is therefore most often correlated to increased crop yield.
Adding nitrogen to a farming system enables increased productivity, allowing farmers to either produce more food with the same amount of land, or to produce the same amount of food while retiring parts of a farm from production.
Without the inputs needed to farm efficiently, more land - either in New Zealand or around the world - would need to be converted to farms in order to avoid millions being without food.
Those who demand a ban on synthetic nitrogen fertilisers castigate the product because of its association with intensive agriculture.
But it is this very intensive (or efficient) farming in New Zealand, enabled by synthetic fertiliser, that has empowered a small number of farmers on a relatively static amount of land to feed over ten times our population.
The world before synthetic nitrogen was simply not a better place; crop failure regularly resulted in widespread hunger, popular authors published books on the imminence of a cataclysmic global famine and explorers scoured the world for organic sources of nitrogen with little regard for the environmental and social impacts of doing so.
Today hunger is such a rare occurrence for many, it is difficult to believe that this dystopian world existed only a century ago.
It is possible for farmers to obtain nitrogen from sources other than synthetic fertiliser, but alternative sources such as animal manure or nitrogen-fixating legumes would not work for some farm systems and would not provide a complete replacement.
This is what has led most farmers to purchase the product at great expense.
The value derived from the critical input quickly flows from farmers to the wider economy, with research estimating a that a blanket synthetic nitrogen fertiliser ban would cost the New Zealand economy a staggering $19.6 billion and over 70,000 jobs.
Despite three quarters of the air being comprised of nitrogen, this nitrogen is cruelly in a stable form that cannot be absorbed by plants.
The history of agriculture is synonymous with farmers searching for new and novel ways of obtaining nitrogen-dense materials to enrich crops with, with evidence showing animal manure being used as long as 8,000 years ago.
Historically, European farmers were content to use livestock manure as the dominant source of nitrogen but when it was discovered in the mid-nineteenth century that bird manure deposits contained large amounts of essential nutrients, a gold rush for this guano was triggered.
As unbelievable as it sounds in the modern context, the search for guano and the accompanied spike in crop yields, led European powers to indiscriminately mine far flung islands that were the home of sea birds.
This insatiable demand for guano led to a boom that devastated sea bird populations, resulted in the exploitation of migrant workers and even led to violent conflicts over mining rights.
Despite this, population growth continued to outstrip agricultural productivity gains and many scholars feared the inevitability of an oncoming global famine to end all famines.
In the late-eighteenth century the English cleric Thomas Malthus published his theory hypothesising that due to the exponential nature of population growth and the linear nature of food production, without regular population limiting events such as wars and pandemics humanity would inevitably be devastated by a massive and overwhelming famine.
Malthus was not alone in his thinking and the macabre theory remained popular up to the twentieth century, because after all; one day farmers will run out of additional land to cultivate, explorers will run out of guano islands to mine and ultimately you cannot make food out of thin air.
However, making food out of thin air was exactly what was enabled when in 1908 Fritz Haber developed a process for converting atmospheric nitrogen into ammonium.
This process was later refined and commercialised by Carl Bosch in 1913 and the innovative Haber-Bosch process was used to produce synthetic nitrogen fertiliser that thwarted Malthusian predictions of an oncoming cataclysmic famine.
Malthusian predictions regained popularity in the 1960s, only to again be thwarted by a series of innovations, known as the Green Revolution.
Both Haber an Bosch went on to receive a Nobel Peace Prize for their breakthrough.
Staggeringly, today it is estimated that half the world's population is fed by food grown using synthetic nitrogen fertiliser produced via the Haber-Bosch process.
The production of synthetic fertiliser quickly rendered unnecessary the destructive mining of guano and lifted millions out of poverty. But it also created a problem new to humanity, the environmental impacts of excessive nitrogen escaping farm systems.
In the same manner synthetic nitrogen fertilisers promote the growth of crops and pastures, their overuse can also result in excessive nutrients spurring algal blooms and the degradation of waterways.
Despite the product being an expensive input for many farmers, it's overuse has provided more nitrogen than crops can absorb in many regions in New Zealand, with excess nitrogen seeping into and polluting waterways.
Nitrogen that isn't absorbed by plants or which doesn't flow into waterways is also converted into the potent and long-lived greenhouse gas nitrous oxide (N2O).
Nitrous oxide currently makes up about six per cent of New Zealand's greenhouse gas emissions and the New Zealand agriculture sector is ambitiously committed to achieving a net zero nitrous oxide emissions target by 2050.
While many New Zealand farmers can recall when the government subsidised farmers to use as much of the product as possible, increased understanding of the negative environmental impacts, coupled with intense public pressure, has resulted in Kiwi farmers now rolling out expensive and creative methods to prevent overuse and the negative consequences which result.
New Zealand farmers are hard at work efficiently producing highly sought-after food for the world, while also ensuring as little nitrogen goes into waterways or into the atmosphere as possible. This is not only good for the environment but also good for productivity, as any nitrogen not being taken up by the intended plants is a wasted input.
Our cutting-edge practices blaze a trail for millions of other farmers across the world to do likewise.
Banning synthetic nitrogen fertilisers in New Zealand would be akin to banning fire because of house fires, an absurdly impractical measure that will impede the development of innovative methods for improving environmental outcomes.
The international leadership being demonstrated by New Zealand in producing large amounts of food as sustainably as possible, should be celebrated and improved upon, not undermined.
