“ …Nitrogen is elemental to life. It’s the essential building block of the plants we eat. Farmers remove it from the soil when they harvest the year’s crop, and they must replenish it for the following year’s.
Compared with water and fuel, nitrogen is actually in one sense quite plentiful: it makes up about 80 percent of the air we breathe.
Yet for all that …, it’s also in a sense scarce: it’s extremely strong chemical bond — it exists in the air in triple-bonded pairs of nitrogen known as N2 —
makes it difficult for plants to use”. Tom Philpott*
The history of synthetic nitrogen
It was less than 100 years ago that scientists – while perfecting bomb making – learned how to create readily available nitrogen on a vast scale. The introduction of mass-produced synthetic nitrogen fertiliser revolutionised agriculture, freeing farmers from the burdens of nitrogen fixation and allowing them to grow more food than ever before. Synthetic nitrogen revolutionised society, too: the explosions in crop yields that it helped drive made food cheaper and more plentiful than ever, setting the stage for the 20th century’s population boom. Farmers in fact can blame synthetic nitrogen for driving their returns down but at the same time raising their production costs.
Overuse of Synthetic Nitrogen
Due to the pressure to maximise yields, farmers routinely over-apply nitrogen because plants take up different amounts of nitrogen at different points in the growing cycle. However under optimum conditions and using best practices, plants take up only 50 to 60 % of the nitrogen applied by farmers. Globally, ―about two-thirds of the nearly $100 billion of nitrogen fertiliser spread on fields each year is wasted, that’s a lot of money down the drain and a lot of nitrogen bleeding out of fields in various forms‖ leading to serious problems with not only soil life. We have all heard of blue green algae appearing in waterways, dying coral at the Great Barrier Reef and pockets of literally dead sea around the world. Added to this, the process of generating synthetic nitrogen requires massive amounts of increasingly scarce natural gas. In China alone, the globe’s largest consumer of nitrogen, approximately 100 million tons of coal is used annually to produce 70 percent of its nitrogen supply. This is simply not sustainable.
How do we solve the problems caused by synthetic nitrogen?
Our food system has become reliant on an input that appears to be unsustainable at current levels of use, while our population is growing. How can we maintain a robust, plentiful, growing food supply while also using less synthetic nitrogen? The question is being asked more and more and even the staunchest proponents of industrial-scale agriculture acknowledge the need to use synthetic nitrogen more efficiently. But to date government and agribusiness efforts to address the problem have focused on techno-fixes: for-profit efforts to preserve the current food production system while making it more nitrogen-efficient. One such fix is seeds that are genetically modified to use nitrogen more efficiently. The U.S. seed giant Monsanto and the Israeli biotech firm Evogene are collaborating to identify genes that can ―improve nitrogen use efficiency in corn, soybeans, canola and cotton …‖ Is this the answer?
…to be continued
* Acknowledgements to The N of an era: America’s nitrogen dilemma — and what we can do about it