Don’t believe everything you read. Even if it’s published by the respected journal “Nature”.
A week ago, my eyes about popped out of my head as I read the “World View” column in “Nature” featuring Jeremy Grantham:
Then there is the impending shortage of two fertilizers: phosphorus (phosphate) and potassium (potash). These two elements cannot be made, cannot be substituted, are necessary to grow all life forms, and are mined and depleted. It’s a scary set of statements. Former Soviet states and Canada have more than 70% of the potash. Morocco has 85% of all high-grade phosphates. It is the most important quasi-monopoly in economic history. What happens when these fertilizers run out is a question I can’t get satisfactorily answered and, believe me, I have tried. There seems to be only one conclusion: their use must be drastically reduced in the next 20–40 years or we will begin to starve.
If you don’t know who Jeremy Grantham is, he’s a British investor who is co-founder and chief strategist of GMO, a Boston-based asset management firm managing more than $97 billion. Recently, he’s taken on the subject of the future challenges of global agricultural production, and takes a rather dismal view. Readers love doom in agriculture, and his latest quarterly letters have gained him a devoted following. I’ve begged to differ with a few of his takes on issues as I’ve read these reports, but have kept silent, as I’m not paid to do what he does.
But, after I read the above quoted paragraph, I aborted everything I was doing that day to begin my rebuttal to this outrageous statement. My article was about half-done and that is the way it will stay, because I discovered that Tim Worstall over at Forbes had already written a superb response titled, “What Jeremy Grantham Gets Horribly, Horribly, Wrong About Resource Availability.” What he writes does not only apply to these two fertilizers, it applies to most element mining. He explains to us the difference between reserves and resources. If this is a subject that interests you, you must read Worstall’s writing.
The subject of phosphate and potash fertilizers is frequently mentioned in limits to growth circles as being a defining limit for our future survival. Like every issue when one digs deeper, this is not a simple subject. A current study which you might read about fertilizer reserves is “NPK – will there be enough plant nutrients to feed a world of 9 billions? Supply of and access to key nutrients NPK for fertilizers for feeding the world in 2050″, by Maria Blanco. She mentions the failure to see that the nature of reserves is dynamic.
The USGS publishes official updates on potash and phosphate rock reserves. Blanco, like Worstall, conclude that though there may be official stated reserves of these fertilizers of 300-400 years, they will last far beyond that.
Certainly, however, in the never-ending quest for the best farming methods, those which use less phosphate fertilizer, or reuse it, should be encouraged. That applies to all farming inputs.
To demonstrate the variability of this subject, the farm that I grew up on, and much of the soil in Nebraska doesn’t require potash fertilizer. Before farmers fertilize, they need to know what they lack by doing soil studies, and many fertilizers are overused today. A very interesting soils study which I covered previously also demonstrates the dynamic demand side by showing that some U.S. soils showed increased potassium levels after growing nutrient-hungry corn on them for many years, something that couldn’t be explained by the researchers. There is a reason that PhD’s are awarded to those serious about the study of soil chemistry and science.
We must remember the dynamic nature of soils due to their live inhabitants, too. Mycorrhizal fungus greatly amplifies the ability of plant roots to uptake and reuse phosphorus, for example. There are many other living micro-organisms in healthy soils which are also affecting the supply, balance, and uptake of nutrients by plants.
Farming practices and crop choices also affect which soil nutrients are required. Animal and human wastes and urines contain nitrogen, potassium, and phosphorus and have the potential for recycling. The basic crop and livestock rotation practices of yester-year feed the soils naturally. Agroforestry is all about tree roots fixing nitrogen and potassium to better grow crops in the poor, depleted soils of Africa and elsewhere. Genetic technology holds hope for decreasing specific nutrients required for growing specific crops. And in industrial agriculture, precision agricultural methods are being used so that only the amount of nutrients needed are used, specific down to small areas within fields.
It’s not simple. As the Indigo Girls would say, “There’s more than one answer to these questions,” Jeremy.