In a world where China and India continue to build huge, CO2-belching coal power plants, and a world where global supply chains can no longer be taken for granted, you might think that a small, crowded country like the Netherlands would prioritize home-grown food production over concerns about greenhouse gas emissions from a relatively small volume of cow manure. But this is Europe, the land of eco-utopianism, and so you would be wrong.
Cow poop does emit nitrous oxide (a greenhouse gas) and ammonia (which can potentially pollute local water if uncontained). In a burst of green virtue, the Netherlands has, “unveiled a world-leading target to halve emissions of the gasses, as well as other nitrogen compounds that come from fertilizers, by 2030, to tackle their environmental and climate impacts.” This target is expected to result in a 30% reduction in livestock numbers and the closure of many farms. Dutch farmers are not amused, and have vented their ire by dumping hay bales on highways and smearing manure outside the home of the agricultural minister. Protests over green policies hobbling local farmers have spread to Germany and Canada.
All this raised in my mind the question, could we really get along with using much less nitrogen-based fertilizers? I found a great article by Hannah Ritchie on OurWorldinData.org, “Can we reduce fertilizer use without sacrificing food production?”, which provides lush tables and graphs on the subject.
First, it’s estimated that artificial nitrogen fertilizers (where hydrogen, mainly derived from natural gas, is reacted with atmospheric nitrogen at high pressure over catalysts to make ammonia and derivatives) allow the world’s population to be about twice as high is it would be otherwise. Put another way, take away nitrogen fertilizers, and half of us die. So any campaign to massively scale back on fertilizer usage would result in mass starvation. You first…
That said, Ritchie’s article pointed out that some countries such as China seem to be (inefficiently) using much more fertilizer than they need to get similar results, some countries (e.g. America) seem to be about in balance, and some areas (e.g. sub-Saharan Africa) would benefit from using more fertilizer. So globally we could probably use a bit less fertilizer if the profligate countries used (a lot) less, while the deprived countries used a little more.
I’ll conclude with two charts from Ritchie’s article. The first chart shows, for instance, that Brazil uses twice as much fertilizer per hectare or per acre as the U.S, and China uses three times as much, while Ghana uses about a tenth as much.
The second chart shows estimated nitrogen use efficiency (NUE). An NUE of 40%, for instance, shows that 40% of the nitrogen in the fertilizer is converted to nitrogen in the form of crops, while the other 60% of the nitrogen becomes pollutants. In China and India, only about a third of the applied nitrogen is fully utilized, compared to two thirds in places like the U.S. and France. ( Some countries have a very high NUE – greater than 100%. This means they are undersupplying nitrogen, but continue to try to grow more and more crops. Instead of utilizing readily available nutrients, crops have to take nitrogen from the soil. Over time this depletes soils of their nutrients which will be bad for crop production in the long-run).
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