Global nitrogen consumption in the 20th century

An Unlikely Fix: nitrogen fertilizer and organic agriculture

Written by Adam Merberg

In 1898, the chemist and physicist William Crookes devoted his presidential address to the British Association for the Advancement of Science to “a life and death question for generations to come.” At existing rates, he argued, the world’s wheat crop would cease to be able to feed the world’s wheat-eating people within a few decades. Crookes based his forecast on an estimate of the amount of nitrogen available for the growth of wheat crops. For centuries, farmers had observed that land would become less productive when it was planted year after year. With the advent of modern chemistry, scientists came to understand that these declining yields resulted from dwindling levels of nutrients in the soil as these substances were taken up by crops and removed from the land at harvest.

Rhizobia fix nitrogen in nodules of the roots of legumes.
Rhizobia fix nitrogen in nodules of the roots of legumes (soybean pictured). Photo copyright International Institute of Tropical Agriculture. Used under Creative Commons License.

All life requires nitrogen, which is an important component of many vital molecules, including DNA and proteins. Elemental nitrogen makes up nearly four-fifths of the earth’s atmosphere, but plants and animals can’t use nitrogen in that form. Before atmospheric nitrogen can be used by plants or animals, it must be converted to the biologically available form, or “fixed.” In Crookes’ day, virtually all of the biologically available nitrogen had been fixed by microorganisms known as diazotrophs, such as the bacteria of genus Rhizobia in the roots of legumes like beans, clover, and alfalfa. European and North American farmers had begun augmenting yields by importing nitrogen-rich bat guano from Peru and sodium nitrate from Chilean mines. However, these were not unlimited resources, and Crookes reasoned that unless something were to change, the lands available for wheat cultivation would cease to be able to produce enough wheat to meet world demand by the 1930s.
But Crookes emphasized that he intended his remarks as “a warning rather than of a prophecy”; ultimately he predicted that “the Chemist will step in and postpone the day of famine” by discovering a method for fixing atmospheric nitrogen in the lab. Just eleven years later, the German chemist Fritz Haber answered that call, successfully synthesizing ammonia from nitrogen and hydrogen in his laboratory at Karlsruhe. Haber worked with Carl Bosch of BASF to refine the method in the years that followed, and 1913 saw the deployment of the first industrial application of what came to be known as the Haber-Bosch process.1
Global nitrogen consumption in the 20th century
Global consumption of nitrogen fertilizer from Haber-Bosch synthesis.1

Manufacture of nitrogen fertilizers remained limited through the end of World War II. Crookes, it turned out, had failed to account for an increase in arable land resulting from mechanization of agriculture and had underestimated the reserves of sodium nitrate in Chile. However, his basic premise–that a growing population needs a growing supply of nitrogen to feed itself–was sound, and the second half of the twentieth century saw global application of synthetic nitrogen fertilizers increase by a factor of more than 20. The interdisciplinary researcher Vaclav Smil recently estimated that synthetic fertilizers now provide more than half the nitrogen received by the world’s crops.
Unfortunately, this abundance of nitrogen brought a new set of problems. According to a report released in February by the United Nations Environment Programme and several other organizations, excessive fertilizer use contributes to “a growing pollution web requiring urgent action.” As the report explains, nitrogen not taken up by crops contributes to a host of environmental problems, including contamination of drinking water, algal blooms, coastal and freshwater dead zones, air pollution, climate change, and loss of biodiversity.2
Concerns about synthetic fertilizers are not new. In his 1940 text, An Agricultural Testament, the British botanist Sir Albert Howard argued that using synthetic3 fertilizers instead of composts was detrimental to soil health, which he hypothesized was “the real basis of public health.”4 Howard’s work inspired the American J.I. Rodale to found Organic Farming and Gardening magazine, which promoted farming without synthetic fertilizers and pesticides, and Rodale’s publication gave its name to the movement for a more natural agriculture. Though evidence for Howard’s belief that synthetic fertilizers lead to poor public health remains scant, the organic movement remains alive and well today, and leading organic advocate Michael Pollan now argues that “the whole point of organic food is that it’s more environmentally sustainable.”
This shift in rationales underscores a key feature of the organic movement. Namely, organic does not establish its objectives (say, environmental sustainability and human health) and commit to supporting the agricultural practices which best achieve those goals, updating its methods as science comes to better understand how these goals might be achieved. Instead, it starts from the axiom that natural is best and adapts to new scientific evidence not by rethinking that heuristic but by updating the measure of its success.
According to organic advocates Tom Philpott and Barry Estabrook, we don’t need synthetic fertilizers at all. Both argue that organic agriculture can produce enough food for the world’s population based on comparisons of yields of organic and conventional farms. In cooking terms, comparing the yields (the amounts of crops produced on an acre) of organic and conventional farms is like comparing the end product of different recipes. That’s important if you’re trying to decide what to make for dinner, but even the best-tested recipe is useless without the required ingredients. Likewise, no agricultural system works without nitrogen. Rejecting synthetic fertilizer, as organic does, would leave us reliant on biological nitrogen fixation by diazotrophs (primarily in the roots of legumes on farmland) for nitrogen. Only so much biological nitrogen fixation can take place on a plot of land in a year, so it’s important to ask whether we can get enough nitrogen this way. Arguing for all-organic agriculture without being able to answer that question in the affirmative is a bit like promising your dinner guests a wild mushroom risotto without making sure that you can find enough chanterelles.5
Christos Vasilikiotis also falls short in arguing that organic agriculture can feed the world. He acknowledges the need to demonstrate the availability of organic-approved nitrogen, but he does not estimate the potential for biological nitrogen by diazotrophs, instead pointing out that “EPA estimates indicate that US livestock operations generate one billion tons of manure per year; most of this is not utilized in agriculture.” While it seems unlikely that manure from US livestock could be utilized by farmers in China (which now uses a third of the world’s synthetic nitrogen fertilizer) or sub-Saharan Africa (where the UN report identifies environmental damage from too little nitrogen rather than too much), Vasilikiotis’s analysis also suffers from a deeper flaw which arises from a loophole in the organic philosophy.
Organic agriculture does not prohibit the application of nitrogen that has been fixed by the Haber-Bosch process. Instead, it forbids the use of synthetic fertilizers and allows the use of animal manures, including those produced by conventionally-farmed animals. This means that taboo synthetic fertilizers taken up by feed grains become all-natural–and certifiably organic manure as they pass through an animal’s digestive tract.
By identifying manure as a source of nitrogen, Vasilikiotis dodges the issue of nitrogen fixation entirely. However much nitrogen exists in manure today, much of it has been fixed industrially before being taken up by corn plants and laundered through the guts of conventionally-farmed animals. Vasilikiotis does not explain how that manure might come to be in an organic world. To do so would require demonstrating the potential for sufficient biological nitrogen fixation.6
The Nitrogen in these BBQ Ribs came from the Haber-Bosch process.

A further source of confusion is the misconception that animals make nutrients. Animals do not fix nitrogen or (aside from one known exception, the shipworm7) acquire significant amounts of nitrogen directly from nitrogen-fixing bacteria. Nor do they make other nutrients, like phosphorous and potassium, so their manure contains no more nutrients than their feed. This is a point which Dan Barber, the influential New York eco-chef, seems to miss when he urges environmentally-conscious New Englanders to eat “a lot of meat” in part to avoid dependence on synthetic fertilizers. According to Barber, it’s important to raise a lot of animals so that we’ll have enough manure, which he terms a “free ecological resource,” to fertilize our vegetable crops. This advice stands in stark contrast to the recommendations of the UN fertilizer report, which explains that “inclusion of livestock in the food chain substantially reduces overall nutrient use efficiency, leading to large pollution releases to the environment” and identifies as a “Key Action” the reduction of animal protein consumption in affluent regions.
The discrepancy is explained by considering the Stone Barns Center for Food & Agriculture, the small non-profit farm which raises meats for Barber’s Blue Hill restaurants and is, in Barber’s words, ”a replicable model for the future of good food.” At Stone Barns, the manure of pigs, chickens, geese and turkeys is largely derived from feed of corn, soy, sunflower, and flax. While sheep, the farm’s ruminants, may take in some “free” nutrients like nitrogen fixed in the roots of clover on the pasture, that pasture is fertilized in part with the manure of grain-fed animals, so even their manure is made possible by the grain inputs.
That’s important because the nutrients in grains need to come from somewhere. Manure from grain-fed animals doesn’t solve the problem of soil fertility so much as transfer that problem to the grain farm. And although animal manures are natural, they aren’t entirely benign. Like synthetic fertilizers, nutrients in manure can run off in groundwater or escape into the atmosphere. This means that growing grains for animals to produce manure for vegetables tends to increase pollution by adding another opportunity (on the grain farm) for nutrients to escape. While recycling nutrients in manure is more efficient than discarding them, the possibility of doing this does not amount to a strong argument against reducing nutrient inputs, an end that would be achieved by eating grains and legumes in place of grain-fed meats.
Barber’s advice highlights the perils of the organic movement’s attitude towards natural and synthetic materials. To organic, industrial fertilizers should be avoided because they are synthetic, and manure is permitted because it is natural. This preempts any discussion of the actual environmental issues surrounding fertilizer use, so it’s unsurprising that we hear pronouncements like Barber’s which stand to exacerbate those problems.
The misconception that animals make nutrients also tends to obscure a basic fact about the problem of fertility in agriculture. Pollan says in the documentary Fresh that by fertilizing crops with manure, farmers “close the nutrient cycle,” but this terminology can be misleading. Farms lose nutrients with the harvest of crops, even if all animal manure is recycled.8 This stands in contrast to natural ecosystems, where nutrients removed from land in food return to the land when the animal defecates. Natural processes, like atmospheric nitrogen deposition9, can help replenish some nutrients, but the fact remains that the nutrient cycle remains open. Maintaining modern yields generally requires inputs of some kind to replace nutrients removed in crops. For instance, Joel Salatin’s Polyface Farm–which Pollan’s The Omnivore’s Dilemma identifies as a model for sustainable agriculture and describes as “completely self-sufficient in nitrogen”–actually brings in nitrogen in conventionally-grown grain10, which is fed to chickens whose manure fertilizes the pasture.
For centuries, farmers in China strived to close nutrient cycles by fertilizing their crops with human excrement. In the early twentieth century, the American agricultural scientist F.H. King argued that this practice had been critical to the perennial fertility of Chinese farmland and identified the Western method of sewage disposal as a major reason for dependence on fertilizers. Over the years, the idea of reusing human waste in agriculture has earned the support of an unlikely alliance of agricultural figures, including not only Albert Howard, but also food movement hero Wendell Berry and Justus von Liebig, the German chemist vilified by organic advocates for his discovery that plants need mostly nitrogen, phosphorous, and potassium from soil.
In recent years, the US government has begun allowing the recycling of human waste by authorizing the use of treated sewage sludge, called biosolids, as fertilizers. However, in 1998 organic advocates successfully protested proposed guidelines which would have allowed application of biosolids in organic agriculture. Whatever the merits of their objections11, it is ironic that the movement for a more “natural” agriculture now opposes ending the waste of nutrients that Liebig once decried as “a sinful violation of the divine laws of Nature.”
All of this is to say that the problem of fertility in agriculture is deeply unnatural. Nature has inspired many good ideas, like crop rotations and recycling of nutrients, and the UN report makes clear that these practices, along with reductions in food waste and meat consumption, will be important parts of efforts to mitigate the “growing pollution web.” That said, nature does not take an interest in the well-being of humankind, so it seems unwise to expect it to solve the problems that we have created for ourselves. Too much synthetic nitrogen fertilizer causes problems, but that doesn’t mean the solution is to use none at all.
Meanwhile, emerging technologies, such as wheat genetically engineered to use nitrogen more efficiently and chemical treatments to reduce nutrient pollution from manure12, aim to lessen the environmental impact of agriculture. Organic agriculture won’t allow these, and, to be fair, it remains to be seen whether these technologies can succeed in that end. However, we ought to make that determination based on evidence, instead of dismissing these tools for being unnatural.

  1. A good history of nitrogen in agriculture and the development of the Haber-Bosch process is found in Vaclav Smil’s Enriching the Earth: Fritz Haber, Carl Bosch, and the Transformation of World Food Production. This book is also the source of the data for the nitrogen fertilizer consumption graph.
  2. A more thorough account of the consequences of nitrogen pollution can be found in this recent Slate article
  3. Howard actually directed his criticism toward the use of “mineral fertilizers,” which includes Chilean nitrate as well as industrially-synthesized nitrogen. As has been mentioned, in Howard’s day application of synthetic nitrogen was relatively limited, and much of the mineral fertilizer in use was in the form of Chilean nitrate. However, Howard’s main concern, that mineral fertilizers did not contain organic matter, applies equally to either.
  4. This quote does not come from An Agricultural Testament but from Howard’s later book, The Soil and Health: A Study of Organic Agriculture. In context, it is clear that he is summarizing the hypothesis put forward in the earlier book.
  5. Even claims that organic yields can match conventional yields are dubious for many crops, as a review published in Nature last year found. According to Nature News, one author of the paper suggested that lower yields in organic systems might be largely due to nitrogen deficiencies.
  6. One study has claimed to show that nitrogen-fixing cover crops could replace synthetic fertilizers, but that study left much to be desired. Karl Haro von Mogel has raised a number of criticisms, pointing out that this paper assumed that no croplands were already planted with cover crops and that all cover crops could be cover cropped every year. It is also worth pointing out that the paper’s estimate of potential for nitrogen fixation from cover crops did not include any data from farms in China, where a third of the world’s synthetic nitrogen is used.
  7. This is according to page 78 of John Postgate’s Nitrogen Fixation (Third Edition). This book is also a good resource on biological nitrogen fixation in general.
  8. It should be pointed out that in practice, some nutrients are consistently lost from manure.
  9. While atmospheric deposition can provide fertility to agricultural land, it is often a pollutant.
  10. In fact, Pollan describes Polyface Farm as “completely self-sufficient in nitrogen” and, in the very next sentence, states that it brings in corn from another farm.
  11. Organic advocates tend to argue that application of biosolids constitutes a public health hazard. Notably, the Organic Consumers Association condemns biosolids as “toxic sludge” and “poison.” These claims are not supported by a report by the National Resource Council of the National Academy of Science, which found no evidence that existing policy on biosolids had failed to protect public health, but acknowledged a need for additional research. Slate also recently ran a good popular article on biosolids.
  12. The possibility of decreasing pollution by treating manure is identified by the UN report as one way to reduce losses of nitrogen to the air. See page 64 of the PDF.

Written by Guest Expert

Adam Merberg has a PhD in Mathematics from the University of California, Berkeley, with a dissertation on noncommutative probability theory and operator algebras. He sometimes reads, thinks, and writes about food and agriculture issues when he’s not busy with his work.


  1. Yes, yes, and yes. This article reminds me why I am so ovah the organic thing. I used to be a believer in it, but I poisoned my belief with rational thought.
    One experience I had while working on an organic farm: I was “the tractor guy,” which meant that I had to spread lots of manure imported from a local cow farm and turn lots of compost with a bucket loader. I remember contemplating the sources of all the vegetable matter that we were composting and poop we were spreading: was it coming from the farm? NO. As I said, the manure came from a local NON-ORGANIC cow farm, and the vegetable waste came from college cafeterias, restaurants, and grocery stores.
    We were very proud of all this “natural” compost we were spewing out the back of our manure spreader, but I could never get over the fact that the N, P, and K in that compost was coming from commercial food suppliers and “factory” farms, and that means, ultimately, the N was coming from an ammonium factory somewhere.
    Now, on my own small CSA farm, I still use some vegetable compost, and manures from our hobby cows, and I don’t sweat having to supplement it with a little bagged N now and then. But my “holier-than-thou” beliefs have gone by the wayside, and good riddance.
    With complex issues like this, it is so easy to fool yourself….

  2. This myth is oft repeated. Often in arguements against vegetarianism/veganism – “you need animals to fertilize the soil” they’ll state with brash certainty.
    Oh really? I’ll respond, and whence the nutrients to build the animal? When did animals start fixing nutrients? They don’t. They use them up and spread ’em further. One can, perhaps, use a cow, or a sheep, to move nutrients fixed by a clover field back to a barn where they’ll expel them for pickup and redistribution to your corn fields (or whatever you grow!) but you’d likely (I think, and perhaps here I’m not entirely right) be better off simply having non-graxed pasture in the prior year’s rotation (Soy grown before corn leaves the equivalent of approximately 60lbs of applied N per acre in the soil (which ain’t enough for production levels in most fields, but is certainly enough that you actually get some corn rather than barren ears)

  3. Enjoyed the article. I’d like to see an in depth analysis of the Rodale 30 yr farm comparison which is held up by the organic advocates as being the gold standard and proof that organic can yield as much as conventional. There are other anecdotal stories about farmers in India breaking world records for potato production using only organic methods floating about as well.

  4. One interesting point that I take home from the Rodale data is actually a tale of nitrogen runoff – over the period of time they’ve been running the experiment they’ve had essentially the same nitrogen runoff from their organic as from their conventional fields, which, in my opinion, makes a lot of sense – nitrogen doesn’t really like to stick around, Ammonium would stick about (positive ion in generally negatively charged soil environment) but is quickly converted to nitrates, nitrates are, to paraphrase Ghandi, a complete bugger (negative charge in a negative environment plus also highly soluble). If your yields have approximate parity you likely have about the same amount of nitrogen available in the field, you therefore wind up losing similar amounts. Even biologically fixed nitrogen is problematic (what will proponents of organic do once we drag ourselves out of the dark ages and invent N fixing plants?)

  5. Yes, in fact it was debates over vegetarianism/veganism that led me to look at this issue.
    Actually, Dan Barber has even chastised vegetarians for eating “soy burgers that rely on pesticides and fertilizers.” Of course, as you note, because soy is a legume, it provides fixed nitrogen by hosting nitrogen-fixing bacteria.
    Some people argue for raising animals to recycle plant material that people won’t eat, and that seems much more sensible than saying that we need animals to fertilize the soil. For the objective of reducing nitrogen pollution, I’m inclined to believe that soy burgers tend to be better choice than beef burgers (even grass-fed).

  6. Adam
    What you say is true, but it’s pretty well understood by most people working within organic agriculture and there are plenty of examples of closed loop organic systems using green manure leys (or closed-ish loop anyway – nitrogen you can cycle, whereas phosphate is trickier, but that’s true of ‘conventional’ as well as organic systems).
    Whether organic systems can feed the whole world or not is highly debatable, but I don’t see why it has to be inferred from your analysis that there is something intrinsically wrong with organic agriculture. Conventional agriculture currently relies on synthetic nitrogen fixation using fossil fuels, so is clearly not sustainable in the long term as it stands. It remains to be seen whether global agricultural production can be powered by synthetic nitrogen from renewable sources. In the mean time, I’d have thought it’s a pretty good idea to use nutrient cycling and organic methods wherever possible in order to minimise non-renewable fuel use. And in terms of global equity, it wouldn’t be a bad idea to prioritise synthetic fertiliser use for poor farmers on poor soils (eg. in parts of sub-Saharan Africa), rather than grabbing so much of that resource for the over-fertilisation of already nutrient-rich soils in the wealthy countries of the temperate north.

  7. I’m not totally convinced by the recycling plant material people won’t eat arguement – I often hear this about best uses of land which isn’t good enough for crop growth, I always wonder if it wouldn’t simply be better just to, y’know, leave said land completely out of the equation (or if it is rotational… just leave it be, as I said, 1 year of soybeans (which get harvested, and thus have a massive amount of nitrogen removed from the system) equates to something in the region of 60lbs applied N / Acre – I assume clover etc does better due to not removing a ton of N with a harvest, plowing it back in, I would imagine, isn’t that massively different from having animals process it – we don’t *have* to farm every available acre (another oft repeated arguement for raising and eating animals “only use of that land” – oh really? What’s it gonna do, float off into space if you don’t use it?
    Also, if it is post human use, rather than stuff laying about, what’s wrong with composting – I’d assume nutrient retention is somewhat better and that the GHG emissions are probably lower or at least at parity.

  8. Possible to get the nitrogen use data from your graph as a flat file? I’d like to overlay that on the historic yields from the Duvick papers.

  9. “in the mean time, I’d have thought it’s a pretty good idea to use nutrient cycling and organic methods wherever possible in order to minimise non-renewable fuel use.”
    I’m in agreement with you here – but wanted to point out that many non-organic farmers do use nutrient cycling methods like growing legumes or cover crops (even though they might not call it organic). Actually, I prefer not to call these methods organic because it implies that conventional farmers can’t/won’t/don’t use them.
    “in terms of global equity, it wouldn’t be a bad idea to prioritise synthetic fertiliser use for poor farmers on poor soils (eg. in parts of sub-Saharan Africa), rather than grabbing so much of that resource for the over-fertilisation of already nutrient-rich soils in the wealthy countries of the temperate north.”
    Great point! Although that’ll never happen – the ones with the money get the inputs. I would like to see more creative technologies to produce N closer to farms, with a decreased reliance on fossil fuels, which will help both in developed and developing countries. For example, here’s a creative way to make ammonia from biofuel waste (although of course, hopefully they’d use a crop for biofuel that isn’t as N intensive as corn!). We should also be capturing N from liquid manure (including human manure). Methods that use N more sparingly such as injection or well timed application can help a lot too.

  10. Beginning 2012, I published an analysis of a document from the Swiss Research Institute of Organic Agriculture (FiBL):
    The (critical) analysis pertained essentially to allegations made out of a 21-year long comparative trial of conventional, organic and biodynamic agriculture.
    The trial is the basis for the often-seen statement that yields are only 20% lower in organic compared with conventional, with a reference to Mäder et al., Soil Fertility and Biodiversity in Organic Farming (Science v.296, n.5573, 31may02).*
    Guess what?
    Most if not all of the background material published on the Internet by FiBL and other entities supporting organic agriculture has been removed!
    *  The key statement is: « We found nutrient input (N, P, K) in the organic systems to be 34 to 51% lower than in the conventional systems, whereas mean crop yield was only 20% lower over a period of 21 years (Fig. 1, Table 1), indicating an efficient production. In the organic systems, the energy to produce a crop dry matter unit was 20 to 56% lower than in conventional and correspondingly 36 to 53% lower per unit of land area ».

  11. Thanks for those comments Anastasia. Although I (a) agree with what you say, (b) am not looking to criticise conventional farmers specifically, and (c) don’t necessarily agree with everything associated with organic farming, I think the anti-organic tone in much of this thread (not in your comment) is problematic. True, non-organic farmers increasingly do use nutrient cycling and cover crops, and think about soil organic matter, rotations etc but let’s give some credit where it’s due and acknowledge that the organic movement has spearheaded all this in the face of general indifference and/or hostility over several decades, and its approach has been vindicated.
    Per acre yields are important, but they tend to get excessive airplay from those who are basically more interested in criticising the organic movement than in constructing a sustainable agriculture – there are so many other issues, such as food waste, tenure systems, input equity, carbon costs, feedlot meat, system stacking, downstream external costs and so on that need to be put into the mix. So yes by all means let’s bust a few myths about where the nitrogen comes from, but let’s use that to initiate a proper debate about sustainable agriculture rather than just using it as ammunition against organic farming.

  12. Thanks for your comment. I don’t think we’re too far apart on things, really.
    I don’t take issue with organic production methods so much as its ideological basis. I would also like to see greater adoption of many of the methods encouraged by organic agriculture. I’m not entirely behind the idea of minimizing non-renewable fossil fuel use, though. I would certainly like to see reductions in fossil fuel consumption, but where there are tradeoffs with land use (which there often are in discussions of fertilizer), I think land use issues also need to be taken seriously. In particular, I think it’s worth keeping an open mind to technologies like precision fertilizer application.
    Incidentally, though, I don’t think that the organic movement would accept synthetic fertilizers even if they weren’t fossil fuel intensive. Certainly, Albert Howard’s critique of fertilizers had little to do with fossil fuel concerns. Then again, the modern organic movement has strayed considerably from Howard’s vision, so I could be wrong here.
    I also agree with you on prioritizing synthetic fertilizers for places like sub-Saharan Africa. That would be great. I would be less comfortable imposing serious cuts on China, simply because its population density is so high, but even there I have seen some studies that suggest that significant cuts could be made without losing yield. However, there is little question that the US could be using less nitrogen fertilizer.
    You seem open-minded on these issues, which I appreciate. If I had seen a similar open-mindedness in the broader organic movement, I doubt I would’ve felt compelled to write a piece like this one. You seem to agree with me that we might need nitrogen fertilizer, and that over-application of fertilizers is a problem. In this case, is it not also reasonable to suggest that we should keep an open mind to nitrogen use efficiency crops, even if they happen to be transgenic? We can debate standards of evidence that ought to be required for planting transgenic crops, but organic doesn’t do that. It just prohibits those crops altogether.
    Organic deserves credit for employing a lot of good methods, and perhaps I’ve come down hard. However, the organic ideology also implicitly shuts a lot of people and approaches out of the conversation about agricultural sustainability, and I think that deserves criticism.

  13. Here’s the data.
    year, N fertilizer (kt)
    1920, 150
    1925, 600
    1929, 930
    1935, 1300
    1940, 2150
    1950, 3700
    1955, 6800
    1960, 9540
    1965, 17900
    1970, 30230
    1975, 43050
    1980, 59290
    1990, 76320
    1995, 78240
    2000, 85130
    It comes from one of the appendices in Smil’s book. He cites International Fertilizer Association data. Some of it is available online, but the online database doesn’t go back quite as far as this. FAO has some data as well but I think it only goes back to the early 1960s.

  14. Two cents from the minuscule farmer and lay observer:
    I don’t think you come down hard enough.
    The “organic” movement has been issuing calumnies against us so-called conventional farmers from the get-go (there is no such entity, by the way). From the Organic Consumers Association to the Environmental Working Group, there has issued an endless propaganda campaign against “toxins,” “frankenfoods,” “unsustainability,” and the host of other bugbears.
    As a former associate with the “organic” movement, I discovered several absurdities in the standards or fact sheets that led me to reject the ideology–to run screaming for the EXIT, in fact.
    1. The Naturalistic Fallacy is ensconced in the National Organic Program’s description as its central tenet:

    In general, synthetic substances are prohibited unless specifically allowed and non-synthetic substances are allowed unless specifically prohibited.

    In other words, man-made (“synthetic”) substance are not OK, unless they’re OK, and natural (“non-synthetic”) substances are OK, unless they’re not OK.
    The whole spectrum of plastics, liquid fuels, and alloys one regularly finds on an organic farm are not even mentioned.
    2. They fib about pesticides. When I worked at an organic farm, I was shocked that I had to be trained and certified as a pesticides applicator. That’s because I was operating under the illusion that Pyganic, Neem, and the rest of the sprays we used were “natural” and therefore not “toxic.”
    Groups like the EWG spread lies on a yearly basis about “pesticide loads” on “conventional” produce, when the very government documents they work from show that farmers have instead performed spectacularly: The residues on produce fall far short of FDA tolerances, sometimes by several orders of magnitude. This never stops the EWG from publishing their egregious “Dirty Dozen” list every year. (Steve Savage has reported extensively on this scandal.)
    3. The absolutist, dogmatic approach to “synthetic” products means that livestock farmers who wish to be certified “organic” can never use antibiotics therapeutically:

    (c) The producer of an organic livestock operation must not:
    (1) Sell, label, or represent as organic any animal or edible product derived from any animal treated with antibiotics, any substance that contains a synthetic substance not allowed under § 205.603, or any substance that contains a nonsynthetic substance prohibited in § 205.604.

    Then, in almost the next breath, it says:

    [(c) The producer of an organic livestock operation must not:]
    (7) Withhold medical treatment from a sick animal in an effort to preserve its organic status. All appropriate medications must be used to restore an animal to health when methods acceptable to organic production fail. Livestock treated with a prohibited substance must be clearly identified and shall not be sold, labeled, or represented as organically produced.

    The absurdity of this is breath-taking. It acknowledges the critical role of antibiotics in the treatment of disease while forbidding its use.
    This then leads some “organic” organizations to promote the worst sort of woo and “alternative” therapies. For example, here in Maine the “Raising Organic Livestock” fact sheet promotes herbal “remedies” and homeopathy. For mastitis they recommend

    garlic internally 1 or 2 whole bulbs twice per day

    Dilute garlic tincture in vulva

    2 oz. raw apple cider vinegar daily internally

    tea of 1oz/qt water ginger, goldenseal, Echinacea, clove grated garlic, juniper berries, celery seed, dandelion root, and leaves, thyme, pine needles cayenne pepper,
    cinnamon, allspice and clove, bring to boil then steep 3-4 hours.

    Homeopathic remedies (Bryonia, Phytolacca, Heparsulph, Aconite, Urtica urens, mastitis nosode)

    “Fact” Sheet.
    Read it yourself and weep (or laugh).

  15. Certainly you raise some good points about the National Organic Program. Certainly I wouldn’t defend the NOP against any of the criticisms you raise. However, I don’t think all of these necessarily translate to criticisms of the organic movement because organic advocates have been known to express dissatisfaction with the standards (usually because the standards aren’t “natural” enough). In this piece, I was writing about the organic movement, so I thought it’s quite fair to point out the irony of NOP prohibition of biosolids because that’s a policy that appears to carry the force of the movement. There have certainly been dissenters within the organic movement, but for the most part that was a policy the movement wanted. I know less about the attitudes of the organic movement toward therapeutic antibiotics or “natural” pesticides. Do you know much about that?

  16. Thanks, copied into a file for later use! Looking a little closer I see those are global consumption numbers so wont be apppropriate to overlay with U.S. yields.

  17. Another appendix in Smil’s book gives the following data for consumption of inorganic nitrogen fertilizers in the US:
    Year, N fertilizer consumption (kt)
    1900, 56
    1905, 82
    1910, 132
    1915, 187
    1920, 207
    1925, 253
    1930, 343
    1935, 283
    1940, 380
    1945, 571
    1950, 912
    1955, 1778
    1960, 2483
    1965, 4207
    1970, 6765
    1975, 7801
    1980, 10346
    1985, 10423
    1990, 10046
    1995, 10629
    1997, 11182
    Of course this includes mined nitrates, but that should be a relatively small amount.

  18. Just found a 1997 article by Vaclav Smil in Scientific American that is currently freely available and could be useful to link to in discussions about the need for synthetic nitrogen fertilizers if the people you’re arguing with aren’t prepared to fork out for “Enriching the Earth”:
    I especially like these two paragraphs from the end of the article that neatly sums it up:
    “An early stabilization of population and the universal adoption of largely vegetarian diets could curtail nitrogen needs. But neither development is particularly likely. The best hope for reducing the growth in nitrogen use is in finding more efficient ways to fertilize crops. Impressive results are possible when farmers monitor the amount of usable nitrogen in the soil so as to optimize the timing of applications. But several worldwide trends may negate any gains in efficiency brought about in this way. In particular, meat output has been rising rapidly in Latin America and Asia, and this growth will demand yet more nitrogen fertilizer, as it takes three to four units of feed protein to produce one unit of meat protein.
    Understanding these realities allows a clearer appraisal of prospects for organic farming. Crop rotations, legume cultivation, soil conservation (which keeps more nitrogen in the soil) and the recycling of organic wastes are all desirable techniques to employ. Yet these measures will not obviate the need for more fertilizer nitrogen in land-short, populous nations. If all farmers attempted to return to purely organic farming, they would quickly find that traditional practices could not feed today’s population. There is simply not enough recyclable nitrogen to produce food for six billion people.”

  19. Well, he could be right but it’s interesting how he dismisses behavior change in one short sentence without any evidence, acknowledges the basic common sense of the organic approach while simultaneously trying to undermine it, and pays no attention the additional nitrogen that could be recycled if more of those six billion were producing food for themselves.

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