Peak phosphorus: Quoted reserves vs. production history

This is a guest post by James Ward. James has a background in science and engineering and is ASPO-Adelaide coordinator for ASPO-Australia. This post appeared previously on Energy Bulletin.

By fitting a bell curve to historical phosphate production data, the best fit is obtained by assuming an ultimate recoverable resource of approximately 9 billion tonnes (of which about 6.3 billion tonnes have already been mined). This yields a peak in around 1990. Of course, the USGS claims an ultimate recoverable resource of some 24.3 billion tonnes (i.e. 18 billion remaining); however using this value yields a bell curve that is an inferior match to the historical data. A hypothesis is thus presented whereby phosphorus is considered in two broad forms: “easy” which is able to be mined quickly, but already peaked in 1990, and “hard” which has large remaining reserves and is yet to peak, but cannot be mined as quickly. (In reality there are probably many different forms ranging from very easy to very hard.) Just as with oil, estimates that lump all types of reserve in together will yield a theoretical peak that is high and distant, however the true system may involve periods of decline after exhausting easy-to-get reserves before other supplies come online to replace them. Ultimately we must develop a recyclable phosphorus supply if humans are to continue living on this planet.


Phosphorus is absolutely essential to plant, animal and human life. Since the Green Revolution the global human food supply has grown to depend on high-yield agriculture using artificial phosphorus fertilizers. These are derived from finite, exhaustible reserves of guano (bird and animal droppings) and phosphate rock. For those of us who care whether our children will have food to eat, world phosphorus production is literally a life-or-death issue. White & Cordell have already made an excellent start at addressing this critical issue by applying Hubbert-type bell curves to gain insights into “Peak Phosphorus”. Their analysis assumes a known Ultimate Recoverable Resource (denoted RURR), and uses this value to constrain the set of bell curves being fitted to the data.


If we assume a remaining resource of 18 billion tonnes of phosphate rock (in line with the stated USGS reserve estimate), and add to this the 6.3 billion tonnes that have already been mined, RURR is 24.3 billion tonnes[*]. Assuming cumulative production Q at time t conforms to the following basic relationship:

where a and k are positive constants, and are the fitting parameters.

It follows that the rate of production P is defined as the derivative

which is a symmetrical bell-curve, underneath which the area is equal to RURR. Figure 1 shows the annual and cumulative production predicted using this theory, based on RURR = 24.3 billion tonnes.

Figure 1

This is, for all intents and purposes, the result of White & Cordell’s model, however they use it to urge planning for a low-phosphorus future. However, recent experience of the Peak Oil and Climate Change debates demonstrates the reluctance among politicians, industry, and community to accept a need to plan for even imminent crises. Urging action on a resource peak as far away as 2033 would most likely elicit zero response. White & Cordell’s critical message could easily disappear over the planning horizon set by myopic governments. A far more urgent message is needed since the phosphate supply situation is almost certainly more pressing than suggested by White and Cordell’s prediction of a 2033 peak at production levels approximately 50% higher than today. This is shown by the compelling predictions obtained when one uses the historical performance of the system (world phosphate mining) to predict future behaviour rather than forcing the behaviour to accommodate the URR estimates of the USGS.

Statistically, the predicted curve for P matches historical production with a coefficient of determination (R2) of 0.882. For Q, the R2 term is 0.911. Visually, it appears that the model could be improved since neither the annual nor cumulative production curves provide a match to historical data. The high production peak of 220 million tonnes per annum in 2033 is therefore questionable.

By allowing the phosphate reserve to be adjusted down from the USGS estimate, we can obtain a better fit to the historical data set, for both annual and cumulative production. Figure 2 shows the curves obtained by assuming an ultimate reserve of 9 billion tonnes (including the 6.3 billion already consumed – i.e. only 2.7 billion remaining).

Figure 2

What we see in Figure 2 can only be described as a perfect match for the cumulative production history, and a very good match to the historical annual production figures, including the downturn of the 1990s. The goodness-of-fit is reflected in the R2 values, which are 0.973 and 0.999 for P and Q respectively.

The critical outcome of this analysis is that it suggests the 1990 downturn is a final peak, with no recovery. That indeed presents an urgent message for governments to act on securing renewable, recyclable phosphorus supplies and transitioning towards more appropriate (less wasteful) agricultural methods.

While it may be somewhat overzealous to suggest that the USGS estimate of remaining reserves should be brought down from 18 billion tonnes to a figure as low as 2.7 billion tonnes, it is compelling to see that this figure results in such a good fit to the historical data. This at least suggests that the USGS reserves should be called into question.

Perhaps the best way to frame the debate from here is to suggest that, like oil, the world has been endowed with a given quantity of “easy” phosphorus (e.g. rich island guano deposits in places like Nauru) that can be – and have been – mined quite rapidly, as well as a larger endowment of lower-grade phosphate rock. While the easy phosphate has passed its peak, the low-grade phosphate should be considered separately. Figure 3 shows an example forecast where the total area under both curves (equal to RURR) is 24.3 billion tonnes, but the “easy” phosphorus (purple) is 9 billion tonnes as in Figure 2. Assuming the production history is mostly related to easy phosphorus, the fitting parameters (a and k) for the “hard” phosphorus cannot be established. Therefore, the height and timing of the secondary peak are unpredictable.

Figure 3

Like unconventional oil, the reserves may be big, and given the crucial role of phosphorus in the world food supply, we can expect heroic efforts to bring new supplies online from low-grade sources. However, several significant questions remain:

How quickly can “unconventional” low-grade phosphate supplies be brought online to replace dwindling conventional supplies, and how will we grow food in the interim?

What is the environmental cost (e.g. waste rock, greenhouse emissions, landscape degradation, heavy metal contamination) of mining low-grade phosphate?

How economic will it be to continue mining low-grade phosphate rock as energy costs rise, and how high must the price of fertilizer be to sustain this?

What will we eat when the low-grade phosphate rock runs out?

This last question is really the main subject of White & Cordell’s website, where they are urgently recommending the rapid, widespread uptake of phosphorus recycling to prevent catastrophic starvation due to exhausting our finite fertilizer sources. Unlike oil (which is simply burnt), we have the opportunity to recover phosphorus by closing loops in our food-nutrient cycle. Furthermore, if we fail to learn how to recycle phosphorus, we will find agriculture disappearing – and us with it.


White & Cordell (2008) Peak Phosphorus – the sequel to Peak Oil

Historical data obtained from USGS minerals fact sheets:

[*] White & Cordell used tonnes of elemental phosphorus, not total phosphate rock, so their reserve and production figures were smaller than those used here; however, we are essentially talking about the same thing.

Related Post:

The Oil Drum reprinted an earlier Energy Bulletin post called Peak Phosphorous, written by Patrick Déry and Bart Anderson.

Thanks to James Ward for this post. This is a very worrisome issue that we should be watching closely. Figure 2 is especially worrisome. How can be assure ourselves of adequate supply to keep up agricultural production? Where are there low grade supplies? Is there a way we can produce them? How about recycling? Wouldn't recycling imply recycling all agricultural input?

I don't know if anyone reading this can answer this: I am aware that organic farming most probably can't sustain the production rates that "modern" agricultural practices can achieve... and I do know that specific controlled applications are being experimented with in an effort to conserve fertilizer usage... but how does the phosphate cycle work in organic farming? Would composting alone be sufficient for sustainable production? Is animal manure a neccesity? I've heard of "exhausted" fields coming back into production after years of rest... does the environment add phosphate (albeit at greatly lower rates) back into the fields (possibly through bug carcasses, bird droppings, etc.)?

You don't flush your poop down the river is how it would work.

I know that calcium in the average (Eastern) North Amercan farm soil has been reduced to about 25% and iron to about (?)10-15%(?) of what it was in pre-colonial days (or so the educated scientific guess says).
Can it be replaced (over time) just by going organic, or will people in the future need to haul sea-shells and fishbones inland in order to just survive?

Seaweed is a good amendment. Harvest it, put it on trains, send it to the farms.

I don't know about calcium, but I figure I feed my chickens oyster shells and then compost the egg shells, so I'm most likely IMPROVING the soil quality on my farm.

You are welcome to my calcium phosphate when I'm finished with it

sadly I feel most people would not like the idea of grinding up your bones for fertilizer. How ever my father does want to be dug into his own compost heap. No idea how I'll get that past the local council !!
I'll get him to put it in his will for a posthumous ( pro humus ) giggle !!

Seriously though I think we need a serious effort in place to stop the flushing of NPK down the loo. Be that home composting or centralized re-cycling. But who here will want to deal with their own "waste" ?

Could be combined with methane production to solve a cooking fuel issue.

Just had a thought. When it comes to recycling humans and human waste, we could have a massive problem with persistent pharmaceuticals which could build up in the consumers of the produce. Diclofenac is but one example of a persistent drug that kills vultures.

It seems that if we were to recycle people and human waste that we would become victims of the chemical industry.

Zebra mussels to the rescue?

Farmers that tend to their soil apply lime, which is a compound of calcium or calcium and magnesium. (Typically finely ground limestone.) They usually apply lime to adjust the PH of soil which in turn makes calcium as well as N, P, and K more available to plants. You can get garden size bags of lime at most any garden supply store/nursery. Lime stone isn't exactly "organic" but it is about as natural as you can get. First you need to test the PH of your soil as PH varies widely as well take into consideration what kinds of crops you are going to grow. A surprising number of crops like a slightly acid soil. Go to your local County Agent's office to get all the information you need, free.

I am aware that organic farming most probably can't sustain the production rates that "modern" agricultural practices can achieve.

Actually, that doesn't seem to be true. Peer-reviewed results indicate that organic farming can sustain production rates as high as current farming methods:

"The study compared a conventional farm that used recommended fertilizer and pesticide applications with an organic animal-based farm (where manure was applied) and an organic legume-based farm (that used a three-year rotation of hairy vetch/corn and rye/soybeans and wheat). The two organic systems received no chemical fertilizers or pesticides.
"First and foremost, we found that corn and soybean yields were the same across the three systems,"....the soil on the organic farms steadily improved in organic matter, moisture, microbial activity and other soil quality indicators."

Modern intensive farming isn't done because it's the best way; it's done because it's the cheapest way.

Modern intensive farming isn't done because it's the best way; it's done because it's the cheapest way.

There is some question about that as well. A fair number of people have suggested that seed producers make more money under the intensive farming model than they can under other models, and since they pretty much have a monopoly on telling farmers when and how to plant, they act on that monopoly to maximize their profits (at the expense of affordability.)

Sorry, but that doesn't make much sense to me. Seed producers need farmers as much as farmers need them. Your comment doesn't even fit some crops. For example, rice and sugar cane. No "seed producers" own the sugar cane varies currently grown in Louisiana. The same goes for most of the rice grown in Louisiana, too. Just who are these "fair number of people" and where have they said this?
Finally my observation is that the farmers are usually the driving force behind plant breeders. It is the farmer that tells the plant breeder he needs a variety that he can start harvesting a week earlier, one that sets its fruit higher to make it easier to harvest, and so on. I know this because I used to serve on a committee that allowed plant breeders and researchers to interact with farmers.

Don't know about rice and cane in Louisana but here in the vast midwest where most of the grains(corn,soybeans and wheat) your exposition is just not the way it is.

A bag of seed corn now runs in the neighborhood of $200 and depending on 'population' will seed about 2 and 1/2 acres. GMO can be even higher. The farmer is not in control...The seed companies are ..even to the extend of spying on farmers and taking them to court.

Read a few farmer forums and you will soon see the disdain that most farmers hold for the big Ag seed companies. They pretty much get whipsawed.


Do some research into Monsanto. I'd say more but I'm afraid they'd sue me. ;-)

"Modern intensive farming isn't done because it's the best way; it's done because it's the cheapest way."

Good observation. Not only is modern intensive farming "cheap" it provides tons of cheap food.

Check out the chart at:

It is the most economical way for a handful of people to feed thousands cheaply.

It is the most economical way for a handful of people to feed thousands cheaply.

Provided that the massive amounts of energy input required is also very cheap. In Ecological Economical terms, it is very expensive to use modern intensive farming.

Ooopps. Now I've gotten on topic for a peak oil board. :)

Whoever is giving these guys - points is a moron.

Modern farming is done the way it is done because its the way the Ag corporations can make the most money. Since they control what is taught at land grant schools, this is what county extension agents tell farmers to do.

Farmers aren't stupid though. You will see changes as oil prices go up.

Modern intensive farming does not produce higher yields (if you know what you are doing) and whether it is cheaper is highly debatable.

The Rodale Institute has been doing side by side comparisons of organic and non-organic farming for decades. Yields are just as good.

Modern practices are optimized for corporate cash extraction. Farmers get only a tiny portion of the cost we pay for food and they turn that over to other corporations for inefficient inputs. Mechanized agriculture does lower the cost (and is sustainable - very little biofuel is need to run tractors) but things like fertilizer and pesticide use actually cost the farmer a lot of money.
The large amount of materials that has to be shipped around, extracted, etc. also increase the true cost. We also subsidize farming which lowers the apparent cost of food without lowering the actual cost; and we export subsidized food destabilizing the farming practices in other countries (look what we did to Jamaica, for example) at US taxpayer expense. There are other externalized costs like pollution.
I haven't seen an really good true accounting of the costs of food production by different means but it is very unlikely that it will favor our current wasteful practices. And rising energy costs affect the non-sustainable practices.

Farmers are tricked by propaganda compaigns into using practices that favor the petrochemical and genetic engineering corporations and then the soil is trashed and the beneficial insects and other natural pest controls are destroyed and if they try to switch back they have a transition period where it is worse. Only a tiny portion of agricultural research goes to legitimate farming practices. And the companies that make money off our farmers make sure they see the subset of studies that favor them. Advertising, in disguise, is substituted for education.

Organic food costs more because there is a high demand and perceived value and less competition, moderately higher labor costs (but lower insurance), not relying on subsidies, organic inputs harder to come by, greater transport costs to specialty markets, smaller farms with higher fixed costs, certification costs, cost of adhering to strict standards, smaller markets with higher markup, lack of externalized costs, and farmers need some incentive to take the risk of transition.

Hi Whitis,

I wish it was kosher to bump the 'points' score of your comment to about 1000, because you absolutely NAILED it.

Thanks to the wonders of modern communication the use of intensive propaganda campaigns is now standard operating procedure for big projects like the so-called "green revolution," and the sad fact is that really good liars can fool all the people some of the time.

A pretty good piece of advice is to proactively search for hype, and rejoice when it is found, because it is valuable evidence, an unerring tell-tale, the "softening-up barrage" that precedes an invasion.

In the case you describe the invasion was of our farmland. It once belonged to and supported myriad families with healthy food, with enough left over to support small towns and cities. Now it is owned by corporations and the financial sector, and produces industrio-crops of dubious nutritive quality. Oh let's just say it; the bastards are slowly poisoning us.

It's worse than a pity. It is a crime of genocidal proportion.

The hype proclaims that mechanized chemical farming has been an unparalleled success, when in truth it is a lethal disaster.

The plain truth is that we can feed ourselves, all six billion of us, if we are willing to get dirty and sweat a little bit (okay, sweat a lot.) But, thanks to an incessant avalanche of propaganda such noble activity has been stigmatized to the point that the vast majority of people would actually be ashamed to personally grow the food that they eat.

Compost animal manure? Butcher a cow? Gut a fish? Oh, dear!

We are not ashamed of breathing or drinking, but we have bought into the lie that toiling in the soil is humiliating.

Today is October 12, pretty late in the season one might say, especially for this latitude, but my organic garden is still producing copiously. In fact to prove it to myself I just popped outside and harvested a quick breakfast of broccoli, tomatoes, sweet green peppers, lemon cucumber and kale, with a little cilantro and basil to jazz it up.

I live in the tiny hamlet of Hamburg, Illinois, right at the water's edge of the Mississippi river (yeah, we got flooded this June, including my garden, but that's another story.)

The garden is raised beds, totalling 144 s.f. (13.3 s.m.) and provides all the veggies our family of three can eat. It took two weeks of hard work to set up, two hours a day to water and weed at first, and now a half hour per day to maintain. I would have had storables (peas, beans and corn) but the flood got 'em. Next year that won't happen because I've raised those beds another three feet (using recycled sand bags from the levy... what a cheapskate I am!)I used ZERO chemical fertilizers, pesticides or powered equipment.

Now the point of this is not to brag up my garden. It's to remind folks that anyone south of Minneapolis with a couple hundred square feet of open space could do the same thing... if they weren't ashamed to do so. Northward of there you'll need a little more space, and some simple form of green housing with some of the plants.

So what do I need Archer Daniel Midlands for anyhow? Cheerios, Twinkies, Micky D's french fries and bio-diesel?

Agreed. The only drawback I know that partly more land is needed for the same output.
And it may need more (wo)manpower (what not necessarily is a disadvantage).

Hello James Ward [keypost author] and Gail,

I have much to say on this topic but I need to get to sleep.

For those interested in what I hope to be discussing sometime later: any meaningful discussion of industrial phosphorus[P] has to include sulfur and the huge amounts of energy required for this chemical beneficiation process. Sulfur is predominantly sourced from sour crude and sour natgas: thus the postPeak implications are enormous to P flowrates, besides insufficient Fuels to globally move this I-NPK to the final topsoil square foot.

Have you asked yourself why O-NPK [mammal urine and bird & bat guano] is so valuable? I am not a chemist, so those TODers who are will add much more to this discussion than me if they study the following links:
In the 1840s, scientists found that coprolites could be dissolved in sulfuric acid to produce what became known as superphosphate.

In 1840, Justus Von Liebig wrote, "The crops on the field diminish or increase in exact proportion to the diminution or increase of the mineral substances conveyed to it in manure." Von Liebig was the first to discover that phosphate of lime in bone meal could be rendered more readily available to plants by treatment with sulfuric acid. Sir John Bennett Lawes about the same time discovered that phosphate rock underwent the same reaction and could be used as a source ingredient.

Simply put, insoluble tricalcicphosphate is converted to soluble monocalcicphosphate by reaction with sulphuric acid.

Superphosphate can be created naturally in large quantities by the action of guano, or bird feces, resulting in deposits around sea bird colonies which can be mined. The most famous mining site is the island of Nauru in the South Pacific much of the "soil" from which was mined, creating temporary wealth for the inhabitants, but destroying their environment.
The white allotrope can be produced using several different methods. In one process, calcium phosphate, which is derived from phosphate rock, is heated in an electric or fuel-fired furnace in the presence of carbon and silica[1]. Elemental phosphorus is then liberated as a vapour and can be collected under phosphoric acid. This process is similar to the first synthesis of phosphorus from calcium phosphate in urine.
Uric acid is also the end product of nitrogen catabolism in birds and reptiles. In such species, it is excreted in feces as a dry mass. While this compound is produced through a complex and energetically costly metabolic pathway (in comparison to other nitrogenated wastes such as urea or ammonia), its elimination minimizes water loss. It is therefore commonly found in the excretions of animals—such as the kangaroo rat—that live in very dry environments. The Dalmatian dog has a defect in uric acid uptake by liver, resulting in decreased conversion to allantoin, so this breed excretes uric acid, and not allantoin, in the urine.
Urine is a transparent solution that can range from colourless to amber but is usually a pale yellow. Urine is an aqueous solution of metabolic wastes such as urea, dissolved salts, and organic compounds.
In short, natural processes in lifeforms create the ideal O-NPK for plant uptake. Higher lifeforms evolved to optimize this plant-animal synergy. I-NPK replicates this process, but at a huge energy cost which will be postPeak impossible to have high global flowrates.

That is just another reason for ramping O-NPK recycling everywhere. Have you hugged your bag of NPK today?

Bob Shaw in Phx,Az Are Humans Smarter than Yeast?

Plus I think that cow manure has the highest % of fixed P of any domestic farm animal.


Thanks for helping to keep us aware of this issue. There are a lot of problems that it would be more convenient if they just went away, and this is one of them (so is peak oil, shortages of fresh water, and our overwhelming amount of debt).

Hello Gail,

Thxs for responding. The O-NPK industry started with manual labor long before our use of FFs and I-NPK, and will eventually go back to manual labor once the short single pulse of FFs are mostly exhausted. There are No Substitutes to these Elements.

When the Hubbert downslope really starts hitting, possibly around 30 million barrels/day C+C: We could see 50% or more of the remaining energy going to this I/O-NPK process. That won't leave much energy for other things or other tasks--that is why I think we need to move 60-75% of the labor force to relocalized permaculture.

I don't quite understand what you want to say.

Anyway, the only solution to keep the "white gold" available as long as possible is: rigorous recycling worldwide.

In fact this is not such a new idea, for example Germany has a long record of research, application and discussion on re-using the sludge from wastewater plants as fertilizers.
As far as I understand the main issue is that this apparently "bio-fertilizer" isn't that clean and healthy as one might think, as it also contains an unpredictable cocktail of hazardous substances that have been flushed down in the sewer system.
This lead to bad experiences, for example in one case farmland soil got contaminated with cadmium to levels prohibitive for food crops. Therefore during the past decade(s) the usage of sludges went rather backwards: Due to specific laws in Germany and Austria fertilizing with sludge is limited to certain crops, in Switzerland it is prohibited entirely.
However with the increasing PP conscience new research is being activated (e.g.: )

link to story about suldge
Electric cars will make polution problem by a magnitude worse. unless we police the seperation of waste streams and recycling.
I do regret saying that, it gets worse .
I wish I had been on the terra pertra but that ended days ago. charcoal soils, coke soils ? compost your shit by the 30 gallon drum which gets picked up and replaced with a drum of black soil that you piss on it and then this drum gets picked up and you get paid.

Composting toilets help reduce the contamination from all manner of non-shit that gets flushed down regular toilets, not to mention industrial waste. Where I live, you are allowed to have a composting toilet but required to have a flush toilet. This seems pretty wasteful on one hand but it does give you a place to dump the water used to clean the floor and the strange lifeforms from the back of the refrigerator that you might be unsure about composting. However, many existing bathrooms don't have room for both - but many residences have multiple bathrooms.

In the US, I think you aren't allowed to grow food crops on land that has been fertalized with raw "night soil" for a couple years. But composting at high temperature (humanure) makes it safe for food crops.

Ugh!!! Finally I can share some of the joys of living with the phosphate industry in central Florida and my thunder is stolen!

Phosphate refining uses a LOT of sulfur. The phosphate ore (or matrix) is washed with sulfuric acid to dissolve out the calcium. This makes calcium sulfate or gypsum in massive amounts. For every ton of phosphoric acid produced, some 4.5 tons of gypsum is made. We have about a billion tons of this phosphogypsum and another 30 million tons is made every year. Recovery of the sulfur from the gypsum is difficult and energy intensive at best. Just to make it more challenging, the phosphogypsum is slightly radioactive. Any radium in the phosphate ore is chemically similar to the calcium and follows the same path. The phosphogypsum here in central Florida is about 26 picocuries (or about twice the radioactivity as brazil nuts). The EPA requires phosphogypsum to be stored in massive piles, called gyp-stacks. The one across the road from my office is officially the tallest point in Florida at 325 above MSL. These are truly massive structures.

Also produced in modern phosphate production are phosphate clays and sands. I do not know much about the sands, but the clays are known around here as ’slimes’. They have the consistency of mashed potatoes and will remain plastic for years without giving up the water stored in their pores.

The energy usage in the mining operations is incredible. The drag line machines are multi-story buildings that ’walk’ and swing a bucket able to swallow up the largest SUV. All the ore is loaded into hopper trains and transported to the chemical processing plants. As the ore gets mined out, the operations are moved further and further south. However, the processing plants remain in the same places. The transportation needs are now some twenty miles long from the mines to the chemical plants.

The industry here is also dying. My neighbor now has to drive forty or fifty miles to work each direction since the plant he worked at closed. Industry consolidation is now the big thing. A lot of good information can be found here:

In short: the phosphate industry uses lots of sulfur and energy while mining ores that are not as rich, located deeper underground and are further away from the chemical plants.

Hello TODers,

Can't go to sleep until I post a link to OCP. Please read the various webpages to get a grasp of the huge scale of the operations, giant equipment size, the various ore grades, the beneficiation flowcharts, etc:

They claim 75% of the world's reserves [in the first link]. Imagine if KSA's Ghawar oilfield held 75% of the world's crude! IMO, postPeak Morocco may be the most strategic real estate on the planet.

We are evolved to sit in the dark, we just can't handle starvation.

Whow, what a surprise, Morocco will save us all!!!
Didn't you realize that this is nothing but a corporate website advertizing their products? The phosphate resources in Moroco are nothing new.
But I am surprised that such sites still manage to impress even a two year TOD reader (sorry for the cynism). Be it the lessons from the New Economy Hype or from the Subprime Crash - maybe mankind will never learn it and Smart Storytellers will always find someone to fool.

Let us try to be a little nicer to fellow posters who are doing their best to be helpful.

Yes, OCP is a big player, but the total is way too small, and likely to get smaller in the next few years. We need some sources besides Morocco, and we need to do recycling as well.

Okay, I wrote "sorry for the cynism" and I hope I didn't hurt Totoneila. I didn't mean to criticize him personally, but I am generally quite sensible when I realize that PR, ads or other misleading information is being taken for true. A result of such behaviour is happening right now with the subprime crisis and its consequences...

As I have posted previously, I first heard peak phosphorus discussed by the McGill biologist N. J. Berrill around 1958. He was interested in the theory that the availability of phosphorus might ultimately limit population growth. Berrill sponsored the biologist Julian Huxley for a lecture series at McGill during the late 50's. About that time I learned that peak phosphorus was addressed in the 1928 Aldous Huxley novel Point Counter Point. Aldous probably obtained some of his scientific ideas from his brother Julian.


Get a grip.

Those lying geologists tell us;

Peak oil-world consumption 30Gbpy, world USGS Reserves 2275 Gboe( include tar)--depletion in 75 years. I think we really only have 1200 Gb or 40 years, but then I'm a peak oiler.

Peak nitrogen--not an issue, nitrogen in the atmosphere is unlimited and can be made from (renewable)electricity by Haber Bosch reaction.

Peak phosphate- consumption 150 mtpy, USGS Reserves 18 Gt --depletion in 120 years

Peak potash- consumption 33 mtpy, USGS Reserves 8.3 Gt--depletion in 250 years

If we only use manure and treated sewage(organic farming), crop yields are 30-50% per acre of what we have now. But we produce far too much food--the average american eats 3900 calories per day plus pets, cattle, etc., in India people eat about 2400 calories per day(60% of US).

It is likely that a sustainable organic agriculture can support the current world population even without extracted resources.

(I'm suggesting that Peak Fertilizer is a DISTRACTION.)

This is OT, IMO; the panic de joir is Peak Credit.

Hello Majorian,

Your Quote: (I'm suggesting that Peak Fertilizer is a DISTRACTION.)

I don't think 50,000 kids under five dying each day agree with your assessment:

We, the global pop., have got a lot of work to do quickly if we are going to go all organic. As it is now: People can't afford sufficient I-NPK plus they are not recycling sufficient O-NPK. See Haiti, Zimbabwe, Somalia, Nepal, Pakistan,...

UN FAO says approximately one billion are suffering from food insecurity.

Consumption 150 mtpy: that is with huge equipment and huge energy. How many tons do you get with just manual labor? Also, you need sailboats to move phosphate from Morocco to Brazil if there is no FF boats.

Don't forget that as the ore quality degrades: you have to process much more raw rock to get the same finished ton of MAP, DAP, etc.


For ye have the poor always with you--
Matthew 26:11

A basic truth, the poor will always be with us.
And in a future poorer society there will be more of them.

Fertilizers is for those who can afford them.

Can the poor afford fertilizer?


They can't afford to mine it, to process/manufacture it, to transport it or to properly plant it. But they can collect nightsoil/animal dung and put it in their fields--organic farming.

We in the OECD can't help them with that. Those countries need to do that. They need to constrain their own populations as China does/did.

In fact, you would be downright cruel to hook the poor on fertilizers.

Peak Fertilizer is only a problem for big ag producer countries who make money with supercrops.

Let's look at corn ethanol.
An acre of corn requires 75 pounds of phosphates and produces 400 gallons of ethanol. To produce the equivalent of 150 billion gallons of gasoline ~225 billion gallons of ethanol would take 21 million tons of phosphate each year. The US currently uses 38 million tons per year, so that would increase to 59 million tons per year. We have a 1200 million ton resource in the US which would last 20 years at that rate instead of 31 years without a 100% gasoline replaced by ethanol energy program.

If we were to corner 1/5th of the world recoverable resources of 18000 million tons(50000 MT inferred?) it drop to 61 years from 95 years with current consumption.
But we won't use 225 billion gallons of corn ethanol a year--ever.
We will probably end up producing 30 billion gallons of corn ethanol, so worse case US supplies would last 1200/(38+21*30/225)=29.4 years versus 31.6 years(1200/38) or with imports; (18000/5)/(38+21*30/225)=89 years. The total 'inferred' US resource is 3400 million tons but I'm using the current recoverable number of 1200 here.

In 30 years the US will be heavily dependent on phosphate imports,
probably where we are today with respect to oil.

That's why I think that Peak Fertilizer is many decades further out in the future.

Peak Oil is today, Peak Uranium is ~2030, Peak Phosphorous 2100?
Peak Potash 2200?

I agree that the poor need to learn and practice phosphate recycling.

We probably should also lead by example on that.

"I don't think 50,000 kids under five dying each day agree with your assessment:"

I agree with the gentleman and this is why.

The cause of most starvation is political which often goes hand and hand with war. People starve in Haiti, Zimbabwe, Somalia not because there is a shortage of fertilizer but because their governments are controlled by dictators/autocrats or in the case of Somalia there is no government. In short the people in power don't care about the hungry people or even why they are hungry. If you were to give Somalia all the fertilizer it need free the warlords would seize most of it and resell it for their own benefit, hand out some as political favors; in short waste most of it. Pretty much what they do with food aid now. See further the starvation in North Korea. Who gets the aide food that is given? The ruling elite and the army. I think you will find the number one cause of hunger in the world is political not shortages of fertilizer. If you can get rid of the first the second is much easier to deal with.

"The cause of most starvation is political... "

your close but thats just a symptom.

We have created a global system tha determins who lives and who dies based on one thing, MONEY.

So yes it's political in that politics is MONEY.

Hello Bob,

I was disappointed someone else was chosen to do this keypost...not that it's not well done, but since you've been out front with this, I anticipated seeing you up there. Could you please give me the names of the current I-NPK producer-companies? You can email me if you don't wish to clutter the thread...

Hi Bob ..

I was hugging my bag of NPK and then
It kicked me in the teeth !!

Bought some TRA @ 16.89 ..

Triff ..

What would have to happen for you to be convinced you are wrong?

marjorian is right. There is no chance that NPK will "run out". These elements are relatively abundant, and are not consumed by agriculture, but only assimilated into food, eaten, and finally find their way to the sewage treatment plant. There they can be recovered by the Ostara Process. as concentrated phosphorus fertilizer and sold back to the farmer. Runoff can be controlled by tying the nutrients to organic or slow-release mineral buffers.

Phosphate abundance in mid-ocean ridge basalt (MORB) is about 0.1%
Nitrogen can be fixed from air, using sunlight, by the Farrington Daniels nitrogen fixation process
Seawater contains 800 grams of crude potash per cubic meter.

This post is talking about easy, cheap, concentrated nutrients only. At a higher price, unlimited nutrient production can be supported

It seems like the issues are

1. If we are really going to use these resources, we need to start now doing the hard work of setting up plants to recover the nutrients from sewage, or using whatever other process we decide to use.

2. It is not clear that we really have the energy available to extract the phosphorous we need from sea water. Did you read Mining the Oceans: Can We Extract Minerals from Seawater?

"Get a grip" may have value in that it is pithy, but doesn't do much to refute the OP's article.

the earth's crust and oceans are full of trace elements - "more gold and U in solution in the ocean than has ever been mined!" cornocopians say - meaningless, as the energy and means doesn not exist to extract widely dispersed elements

if your #'s represent what a non-problem this is, why have prices soared? "120 years supply"? at what price? if I have to suck up an appreciable amount of the earth's seawater to access what I need - it's not going to happen. There is a reason that Morroco is making so much $ off "their" rock phosphate deposits - it is the largest and most accessible in the world.

And for those talking of humanure - the overuse of medication and concentrations of heavy metals in human waste will probably preclude it's use on crops for human consumption - until we get our population to have a cleaner waste stream, it seems to me unsafe to even consider humanure in our food chain.

I would imagine even U.S. animal waste (cattle, poultry and swine) are highly contaminated with all of the antibiotics and growth hormones we pump into them - which makes them less than ideal for use on human-consumption crops as well. We need to clean up all wastes if we ever wish to use them to replace iNPK.

As MacDuff says, the problem is that we will "run out" of phosphorus and other minerals, it's that they become so dispersed that it is not economically or energetically feasible to gather them.

In addition, there is the phenomenon of peak production, when production plateaus and falls, while demand increases. As we know from peak oil, this is the point at which problems begin - not when oil or phosphorus "run out."

As far as I know, the handful of studies done this year and last are the first that apply the "peak" idea to phosphorus.

I'd like to echo MacDuff's comments on contaminants in human and animal waste. Big problem. In addition, there is the problem of disease, especially in feces. One has to be careful in handling and processing feces.

Still, if the motivation is there, these problems can be solved.

Bart Anderson

In addition, there is the problem of disease, especially in feces. One has to be careful in handling and processing feces.

Please see the definition of the term fecophobia in the excellent "Humanure Handbook".

Yay for Joe Jenkins! Although, I must say the 3rd Edition cover is pretty boring. (Earlier editions featured a cute girl sitting in an outhouse reading the Humanure Handbook.)

We must close the cycle -- individually. People pour all sorts of stuff down their toilets that I would not put on my garden, so I'm not much of a fan of large-scale sewage-sludge to fertilizer operations. But anyone with a bit of land should find humanure simple and easy, and those on a city lot only slightly less so.

If you're squeamish about faeces, simply collect your urine. It is sterile when it comes out of your body. Dilute it 10:1 and "fertigate" your garden!

Someone mentioned Huxley:

"With your intensive agriculture," he went on, "you're simply draining the soil of phosphorus. More than half of one per cent a year. Going clean out of circulation. And then the way you throw away hundreds of thousands of tons of phosphorus pentoxide in your sewage! Pouring it into the sea. And you call that progress. Your modern sewage systems!" His tone was witheringly scornful. "You ought to be putting it back where it came from. On the land." Lord Edward shook an admonitory finger and frowned. "On the land, I tell you." -- Aldus Huxley, from "Point Counter Point," published 1928

Good book, Humanure Handbook. It's true that fear of feces is overdone... and yet it's a good idea to have a healthy respect for the public health problems that can arise if one is careless.

Turista, giardia, cholera, all sorts of nasty things can be spread through fecal contamination of food and water.

We're blessed in North America to be relatively free from the problems - thanks to clean drinking water, good sanitation and public health policies. But it's a big problem in developing countries. Infantile diarrhea kills many children, and if one doesn't have access to medical care, then intestinal parasites are debilitating.

Urine is much less problematic, and if I remember correctly, it has similar nutrient content to feces. The little book Liquid Gold is a classic, explaining how to use urine and how it's been used through the centuries (e.g., as a beauty aid and as an - ugh!- drink).

So, to me, urine is the low hanging fruit. Feces require a whole other level of caution and complexity.


I don't believe that the heavy metals originate from human waste. The problem is that human sewerage is not kept separate from industrial streams. Re-constructing sewer systems to keep human waste separate from the industrial streams would be prohibitively expensive. Possibly when new subdivisions are created they could build their own sewerage plants and not allow commercial wastes to to enter their plants. The organic wastes from these could be recycled. However, transportation costs for solid organic wastes would be high due to the low density and large volumes of of processed solids. With increasing fuel costs this could make these materials prohibitively expensive.

The mineral apatite which is chemically similar to teeth is widespread through many rocks at around 0.25% by weight. Thus a block of granite one metre cubed may contain 6 kg or more of calcium phosphate if only it were readily available after weathering. Perhaps a benefit of charcoal added to soil is that it may help microbes make the phosphate available to plants but that is pure speculation. However that phosphate still needs to be replenished from above.

Perhaps we can overcome the yuk factor in applying humanures to local growing of fruit and vegetables. However I don't see how we can supply enough NPK to broadacre cereal cropping, the so-called 'bread bowl'. The emergence of cheap fossil fuels created the delusion that we can always use machines to extract then bring in concentrated nutrients. We'll just have to pay more for food, after all the government will pay our mortgages.

I notified James Ward, the author of this article, that it had been posted. Hopefully he'll be able to join the discussion. (He's in Australia, so there may be a time issue.)

Some quick responses:

Ignorant asks: "how does the phosphate cycle work in organic farming?"

The history of European agriculture indicates that organic farming, by itself, does not solve the problem. Yields in the 19th century were dropping, and many bright minds were absorbed with the problem of restoring fertility. See Liebig, Marx, and the depletion of soil fertility: relevance for today's agriculture by by John Bellamy Foster and Fred Magdoff.

Returning our "wastes" to the soil is one fundamental principle. In many farming traditions, animal and human waste was valued highly.

There may be ways to unlock the phosphorus that is otherwise tied up in the soil, for example, with micro-organisms. But I don't know that much work has been done on this.


Thanks to Bob Shaw for his continuing obsession with fertilizers (which I share). Bob, I hope you'll feel inspired sometime to write articles so you can spread the message beyond the confines of the TOD readership!


Robert Wilson is right that various scientists have brought up the issue of phosphorus. (More quotes from Aldous Huxley). It would be interesting to read an article about the history of the issue.


majorian writes: "Peak nitrogen--not an issue, nitrogen in the atmosphere is unlimited and can be made from (renewable) electricity by Haber Bosch reaction."

Right - the problem of course is getting the energy for this energy-intensive process, as energy prices continue to climb. And then the fertilizer has to be transported, which takes more energy.

majorian writes: "It is likely that a sustainable organic agriculture can support the current world population even without extracted resources."

We'll find out, won't we?

Bart Anderson
Energy Bulletin

From above link about mining in Morocco:

After screening, phosphate ore is carried from Boucraa to the treatment plants located at Laayoune-Plage on a 100-km long remote-controlled conveyor belt system.

Wow, how mechanically intensive is that 100 km conveyor, eh? Probably quite energy efficient though, and operates on electricity...

You can see the conveyor belt on Google Maps.

Notice how everything to the southwest of the line through the middle of the map is white? The belt leaks. Zoom in for a closer look.

That looks really really cool!

You might want to study the amount of N,P205,K02 that is present in both broiler litter and sludge from hog confinement operations.

Currently in my area both of these are usually spread or injected in some fields. Some is traded to the litter haulers for free litter. They get what is on the floor and deliver new litter. This is of course a very big benefit to them for its nutrient values.

That said you really don't want to live very close to a field that is spread or injected with material. It is very unpleasant to be near.

One guy spread some right near a local church. The church could not have services until the material had dissipated. Which depends on a lot on several factors.

AND if the financial chaos continues then perhaps the confinement feeding operations may become uneconomical and shut down.

Its said that just the state of Indiana could produce enough pork to satisfy ALL the demands in the USA. I suspect this might be true but I never researched it.

My take is that its becoming time , very much so, when we in this country need to quit being so concerned with 'globalization' and the welfare of other countries and start to worry about our survival.

We certainly would never be able to give out aid to others if we collapse anyway.

All countries are going to have to resolve these issues based on their own resources and assests and culture. For us we have surely stepped way, way over the line in the sand.

I mean , come on , I can't pick up anything, except at an auction, that isn't made in China!! So when we get right down to it vast areas of our once great industrial greatness is totally disappeared. Due of course to greed in the corporations and board rooms.

Airdale-the time to sit and think is way over,,its time for action

This is likely an ignorant comment, but we can't actually "run out" of phosphorus, can we? It's an element, so it's never destroyed by using it like oil is. Unless we send it into space, there is and always will be the same amount of total phosphorus on the planet.

I can definitely see the "easy" phosphate peaking. But there will always be "hard" phosphate left. The only question is how hard it will be. (That is, is it spread around the world in such low concentrations that it's extremely difficult to refine it into usable concentrations)

Like you say, we can't "run out" of phosphorus atoms, because the atoms never leave our planet.

But we have no use for phosphorus atoms. We have use only for highly concentrated soluble phosphates, such as can be profitably spread on soil as fertilizer.

I can extend your argument about "running out":

No element is scarce, because it is possible to fuse light elements into heavy ones, or to fissure heavy elements into lighter ones.

If we remove three neutrons from lead, it transmutes into gold. We've actually done this. So we know it's possible.

But you can't drive a car on the possibility of gasoline, and you can't eat the possibility of a meal or live in the possibility of a house.

In practice, transmutation consumes far, far more dollars of energy than it produces dollars of gold.

Therefore it is practically impossible.

Regarding the comments about mammal urine, etc. Now, this is going to sound kind of weird and like a joke of some kind, but it really is not. I have, during a couple of periods in the past, saved empty gallon milk jugs and urinated into them; when I got a gallon saved up I would put it on trees and plants in my garden. Does it turn out I was really onto something? My partner thought I was nuts and yes, it's something of a bother rather than just flushing it away and to borrow Boof's term from above, there is a certain yuk factor. Maybe a more practical application would be the Clivus toilets or some such?

The plants seem to do well -- some first-year apple and pear "whips" especially thrived with this treatment. Can't tell how they're doing now; I broke my leg the next spring and wasn't able to take very much care of them and subsequently moved away.

As for the smell -- one solution would be to do away with feedlots and rely on pasturage for ALL our meat. We need to consume a great deal less of that anyway. The animals naturally disperse their own wastes evenly around the pasture, resulting in less concentration and greater air dispersal of odors over a large area. It is utilized quickly by the plants, as long as you are rotating the animals properly between pastures and allowing recovery time for the grasses and forbs therein. And you are not spending FF energy hauling and spreading manure. As another benefit, it is more humane and the animals are happier, at least while they are alive.

Save the precious "mined" P for much smaller acreages of grain, which would not be eaten by animals but directly by humans as bread, oatmeal, etc. And yes, stop this feed-the-world export mentality; there won't be enough FF to haul high bulk/value products like grain halfway around the world anyway.

I'm a farmer. We've bought chicken litter in the past and had good results with it. This year we went all in and bought a farm with ten broiler houses (each one supports 28,000 birds).

Chicken manure has almost equal parts of the 3 essential elements, but in my opinion is better because of the organic matter and micronutrients it contains (not found in chemical fertilizers).

There are problems. It's bulky so the houses need to be close to where you apply the stuff. Where you'd apply 300 pounds to the acre of chemical, you'll need 4000 pounds of chicken manure. Transportation costs will eat you up if you have to haul it far.

Then there's the smell. I don't have a problem with that but we have people that move from the city and then try to take the city with them. They sometimes complain that the animals in the country shit and that the shit stinks.

When applied to pasture land or for hay production, those crops are heavy nitrogen feeders, and not so heavy users of phosphorous. Over time, in an effort to meet nitrogen needs, excess phosphates build up in the soil.

Corn however uses lots of phosphorous and is thereby well suited. Unfortunatly, almost no one growing corn uses the stuff. Chickens aren't grown where the corn fields are.

Because we have as a country consolidated cattle feedlots, we now cannot effectively use a lot of the manure produced. It also is too bulky (and even less concentrated than poultry maunure). One more example of the reasons big agriculture is probably doomed in the long term.

We need smaller, more nimble, mutlifaceted farms within range of market for the final products.

Manure is not a source material, but instead recycled material.

Someone else mentioned all the human manure and urine being wasted.


That means moving people closer to where food is grown, or visa-versa.

I'd like to start socializing the term "Profligacies of scale". This is an example of just such a profligacy. The silly notion "Let's take all the X and put it in one place" -- so you have consolidated feedlots and then you have to gather and transport the feed, then transport and distribute the manure.

If the animal is allowed to roam a field, it will distribute the manure without any additional effort.

I've been told several times by several people that beer makes a very good fertilizer... and that there's no reason that you can't drink it first.

Beer: 270ppm K,140ppm P, 50ppm Mg, 40ppm Ca, ??? nitrogen (mg/kg) (USDA nutritive standard reference).

Urine would have about 1.82ppm P and a similar amount of K (calculated from figures below) plus nitrogen. Presumably if you drank beer, these quantities would be higher.

Urine and feces

Physiological measurements indicate
that the amounts of plant nutrients excreted via
urine per person and year (2.5-4.3 kg nitrogen, 0.7-
1.0 kg phosphorus and 0.9-1.0 kg potassium) are
larger than the amounts excreted via faeces (0.5-0.7
kg nitrogen, 0.3-0.5 kg phosphorus and 0.1-0.2 kg

That is 331 thousand tons of phosphorous discarded in US urine annually and 6.6 billion tons world wide. Plus about 30 to 50% for feces.
Note that most of the soil nutrients are in urine which is really easy to recycle.

Thus the diarists 9billion tons should have lasted 1000 years if no human waste was recycled, all animal waste was, and we didn't lose any of the applied fertilizer from runoff, erosion, leaching, etc. Of course, most of it is probably lost as runoff. And we lose some of it when we bury people and when we landfill food scraps.

1L to 2L of beer per day (the equivalent of human urine output) would be 0.05 to 0.1kg of phosphorus per year.


Regarding using your urine as fertilizer, I have been doing the same thing, however I am very reluctant to let anyone know I am doing it and empty my jugs under cover of darkness shortly before bedtime.

I have been doing this ever since I took a biochemistry course and found out what urine actually was. Once I knew its chemical composition, I felt so foolish wasting it, along with the perfectly good water required to flush it.

It accelerates rotting in my compost heap as well.

I fear if my neighbors found out what I am doing, they would call up the city and have my house condemned and a toxic cleanup initiated for which I would get the bill.

CL is at $85. So a new poll is needed. As low as 85.12 so far.

David Holmgren in an interview here had some interesting things to say about the use of mined phosphorous in agriculture:

One of the biggest limiting resources in agricultural productivity is phosphorous. It's critical to plant nutrition and animal health, and it's in limited supply. All ecosystems work to maximize to hold phosphorous and recycle it. It's one of the non-renewable mineral resources that humans have dug out of the earth at a few key places around the world in the last hundred years with the aid of fossil fuels and have spread over large areas of agricultural land. Interestingly enough, it's one of the few elements that doesn't get leeched away readily. It's been estimated that in some parts of Australia's farmland that's been intensively farmed for potatoes in a cool climate, that there's enough phosphorous tied up in the soil, locked up, for a hundred years of farming—if you could actually make it available.

Now making it available requires the work of a healthy eco-system. Because nature is used to actually breaking apart this locked up phosphorous in the form of aluminium and iron phosphate. So permaculture systems—especially tree systems, as well as forms of organic agriculture that husband the soil micro-organisms—can mine back out some of that resource. That's one of the positive stories—agriculture hasn't just left a legacy of toxicity and degradation, it's left a legacy of unused abundance. It's been technically difficult to get at, so it's not just like people have pointlessly thrown away fertilizers: it requires more sophisticated soil ecosystems.

Seems a good place to mention vermi-composting / worm composting. A scalable technology which is already quite widely used. As we go further post peak it seems to me the main issues will be building heating, food production, transport and electricity. Promoting local food production and employment is a large part of peak oil adaption as is renewable / nuclear energy. I see composting being scaled up hugely in urban areas, possibly with mechanical shredding / heating to speed up the process. Building airtightness and insulation is easy to improve, but its difficult to add thermal mass to a building. I am a big fan of heat recovery ventilation systems, and my cunning plan is to locate the heat exchanger with a large body of compost to act as thermal mass for the building.
The heat recovery ventilation system could be built into the toilet to allow easy renovation, possibly with a small solid fuel stove to provide heat during the coldest parts of the year and maintain the composting process.

Also bio digesters are simple and scalable, with a variety of feed stocks which can use current natural gas infrastructure and can be used in highly efficient end uses , CHP, home heating etc and has the huge benefit of being a controllable form of renewable energy which IMO would pair very well with wind as they can share the same site
(cattle grazing around the turbines) and improve the capacity factor of the wind project ,most biogas will be produced during summer months and more wind during the winter.

On the upside, this suggests that ocean eutrophication (dead zones), caused by phosphate enrichment from runoff, will decline as the phosphorus supply declines.


I'm new here, so forgive me if this sounds dumb. I know also that this particular topic pertains to phosphorus, but I am looking for resources that compare Quoted reserves vs. production history for oil. I looked everywhere on this site and others, cannot find anything. I also want to know what the record is for so-called "90% reliable" stats for oil. I barely understand the graphs for phosphorus, so please, the simpler the source, the better.

Hi, welcome!
I suggest you start your reading here:

If you have a general question or information then the daily 'Drumbeat' thread is the most appropriate place for it.
Hope this helps.

Most phosphate rock etc, contains fluorine, which makes it insoluble, and these sources have to be treated with a strong acid to remove the fluorine in order for it to be used in fertilizers,throwing apatite onto your garden will do little good. One place where phosphorous is removed from the biosphere, is in burials, where all of the phosphorous, in bones and teeth are buried deep in the soil. I don't know the %P in humans, but there sure are a lot of them.

Phosphorus is the second most common mineral in the human body,
700g in a 70kg person. When the 300 million americans die, they will take 231 thousand tons of phosphorous with them (scattering ashes would help). However, more phosphorous is lost every year in urine and feces.

Maybe this theory of the "easy" and "hard" resources is a good match to another background, which is about the chemical quality of phosphate: As far as I know most resources of phosphorous are contaminated by cadmium and/or radioactive heavy metals (some phosphorous deposits were also used for uranium mining). The deposit of Kola in Russia is said to be the last phosphorous deposit free of cadmium.
Many industrialized countries have a legal cadmium limit for fertilizers, whereas third world countries use the cheaper, contaminated fertilizers.
So maybe "easy" and "hard" classification rather refers to a chemical instead of a technical problem.

Hi drillo
You have asked an essential question.
Heavy metal contamination is critical, especially in systems that benefit from a high level of soil nutrient re-cycling, as in high-yielding high-density population areas like critically important parts of China.
"easy and hard" for mining has not historically matched contamination quality of mined phosphate sources. Early sources were frquently highly contaminated. Only way is to test sources for acceptability.

An agricultural watershed with high-yield grain production and characterized by multipond systems in the Yangtze–Huaihe region of China was selected to establish the historic records of heavy metal pollution by 137Cs-dated sediment cores. The experimental results indicated that the contents of most of the heavy metals investigated, such as Cd, Cr, Cu, Ni, Pb, and Zn, continuously increased in the multipond sediments throughout the past three decades. An inflection point appeared in the 1980s, prior to which all heavy metal contents showed little or no increase with time. Thereafter, the heavy metal contents increased dramatically due to the extensive application of phosphate fertilizers.

Hi all, and greetings from Down Under.

Thanks to everyone for taking the time to read and comment on this article.

One can only agree that the planet will not "run out" of the element Phosphorus. But, like oil, the question is not one of reserves but one of flow-rates. I am concerned about the possible low flow-rate from renewable streams of phosphorus compared with the high flow-rates to which we are accustomed, which must inevitably peak and decline.

I continue to be inspired by the work of folks like David Holmgren and thank the commenter who posted his quote. Permaculture and biodynamic farming methods seem to be more about reducing the demand for external phosphorus inputs, in other words reducing demand rather than increasing the renewable supply. An analogy is riding a motorbike vs filling up an SUV with ethanol. In a future in which all phosphorus comes from renewable sources and flow-rates are smaller than today, like oil, phosphorus efficiency will be the order of the day. This is in strong agreement with the comment by the farmer who said that smaller, more diversified farms will be the future.

Now, the smaller the holding, the more labour input is required (and/or available) per hectare. In the long term, this would translate into a larger percentage of the workforce being employed in agriculture (either explicitly or implicitly - the latter being e.g. backyard farmers like my wife, who forego some paid work to spend more time in the garden producing food). This transition may happen "naturally" by market forces as mining commodity booms subside (as is just starting to happen in my country with China starting to ease off the demand for iron ore) and agriculture starting to attract more people due to increasing food prices (precipitated by declining yields in industrial agriculture). In poorer nations, the balance has probably not moved far from the agriculture-centric economy so it's really just a matter of the rich nations catching up.

I have noticed a lot of comments talking about a future in which there will be virtually no ability to move resources like phosphorus around the planet - as though after Peak Oil, all forms of transportation stop. I find this misleading - even fantasy. Remember, with Peak Oil, we are talking about peak and decline of transport fuels, not an immediate cut-off. Furthermore, the fuel being used to manufacture and transport essential goods (such as food and fertiliser) is a relatively small component of the overall fuel usage (with more going on the transport of new cars, jetskis, sofas and televisions, and even more used to shift overweight people around one-by-one in SUVs). Even in the energy-starved distant future, I can envisage enough energy (fossil or renewable) being available to move essential goods around the globe. How well the market can allocate these resources is another matter, of course. We may find that the world starves to death long before rich people stop driving and flying.

Thanks to The Oil Drum for the opportunity to post some ideas and be involved in this discussion.

James Ward

While we may not run out of phosphorus any time soon, supply could be interrupted, and prices could limit its use. Using a range of more resiliant sources would surely be better than relying solely on international trade in dwindling supplies from Morocco or elsewhere, though i agree this is probably going to be part of the mix for a long while.

humanure toilets and other tight nutrient cycles probably lose the least phosphus to entropy of any techniques for recovery, and use the least energy. it also cycles other nutrients, saves heaps of water, and builds good soil. Its realy pretty clean as well, especially if you compare it to nightsoil n chinese farming.

should also mention dynamic accumulation of phosphorus done by some plants (often those adapted to low phosphourus environments), which can convert trace phosphorus in the subsoil to more concentrated and biologically available phosphorus in the topsoil, all powered by sunlight and self perpetuating...

I think this post adds tremendous value to the understanding of depletion of other natural resources, especially oil. Witness that the search for phosphate started within a few decades of the discovery of oil in the middle 1800's. Therefore I would think the shape of the phosphate discovery curve might also follow a logistic like curve. (You can derive this from applying the Dispersive Discovery model, see this post on TOD. This model assumes that there is a dispersion of search rates governing the exploration in various parts of the world, and that search accelerates with time)

The reason I like to look at the discovery curve, is that it will definitely show an earlier peak than production and we should be well into the tails by now. Googling around I found a neat little trick to understand when peak discovery years may occur, see

If I google the news archives for "phosphate" discoveries, I see this histogram:

The apparent peak is already in the late 1800's. This may be a peak known more for its historical importance or it could be a peak for the USA (as Google shows an American bias). Yet it does suggest that the original discoveries are well past their prime.

I suppose that there is a better histogram of yearly phosphate discoveries somewhere out there, but I figure to do a quick and dirty estimate first.

The next step is to apply something akin to the oil shock model to discoveries, and you will have a good idea of the production curve. This generally shifts right from the discovery profile. It would be interesting to see how the extraction rate has changed over the years.


Soil remineralisation seems to be gaining popularity as we deplete many nutrients and micronutrients from our intensively farmed topsoil. Some claim our food is becoming less nutritious as a result of this too, and soil structure is greatly suffering.

We have purchased some rockdust for applying to an area of our smallholding, and are going to be growing organically, so any thoughts about any negative implications of applying it would be welcome (we have a acid heavy clay soil) ;).

The claims about 'rockdust' need checking. I'd presume ingredients include crushed limestone and dolomite (calcium, magnesium), glauconite greensand (potassium), gypsum (sulphur, clay breaking flocculant) and a phosphorus source. If that is insoluble phosphorus such as crushed apatite bearing rock it needs strong acid treatment then re-neutralising. How much embodied energy and fossil CO2 went into crushing and transporting such ingredients?

You might find your clay soil is already mineral rich but needs amendments to help water penetration and worm activity. Dig in a lot of compost down to say 40 cm and keep it aerated.

Thanks for the reply.

The analysis can be found here. Neither chemistry nor soil science are my strong points, but my intuition convinced me it might be a good idea. I'd certainly appreciate any expertise though.

I agree that the energy to crush the rock to that particle size must have been great unless it is the by-product of another very energy intensive process (that I don't know about).

I realise the clay may already be nutrient rich, and we do also intend to incorporate plenty of 'green waste' compost, but we may not be able to do much digging in since the ground is so waterlogged (especially this year). So getting some nutrients to the top might be a problem, which we were hoping this would substitute a bit.

I think you're right in questioning the ecological merits of rockdust, but given times are about to get quite difficult, sometimes we have to put feeding our families above these broader/global concerns - I hope this very attitude doesn't prove the undoing of our species.

Rock dust: Thanks for posting this, as I kind of alluded to this in a comment below. Plants have grown for millions of years on what amounts to rock dust. Not sure if the commercial product represents your average rock or not.

If you were to put one years worth of one persons urine on 70 square yards of garden, it would add as much phosphorous as the 5kg/yd^2 rockdust adds phosphorus pentaoxide (only part phosphorous and may not be bioavailable).

It would take the urine of 70 people or (one persons urine for a lifetime) (or about 42 tons) to add as much phosphorous to one acre as that level of rock dust, but then it would take 26.7 tons of rockdust. Either way, you are adding a number of other nutrients as well.
Clay loam has a higher phosphorous content then the rockdust (and so, apparently, do most other soils).

But heavily used soils are reportedly 70% deficient in minerals.

We should cut right to the chase here.

If peak oil is true all those mined phosphates (of which every plant on this planet contains about 0.75% Phosphorous in its tissue)will be staying in the ground.

facetiously: one man digging it will take 11 years to take out what a barrel of oil in an appropriate machine will take out in a short order. Bad EROI.

2/3 down the backside of the oil graph means all Mega farming ceases and most farming again becomes organic, using that 0.75%P from old plants, grown in the local area.

Shortly after 2/3 down the graph, Olduvai Theory reduces the number of mouths to feed, so that organic farming becomes sustainable.

Nitrogen, about 5% of a plant's tissue, is the real limiting factor for growing. The average Nitrogen in top soil over the planet is only about 1.5%, largely because it is not stable, leaches out and gasifies. The other elements including phosphorous are not a problem.

Its going to be "Organic or Bust"


Graham, it's hard to say that one factor is THE limiting factor. It depends on the crop, depends on the soil.

One thing that's different about phosphorus is that you can't synthesize it, as you can nitrogen. Also, I'm sure you know, certain plants (like legumes) fix nitrogen. Nothing like that for phosphorus, although as someone said upthread, some cover crops with deep roots apparently can bring up P.

So, as with so many things in biology, the answer is "It depends."

It is interesting that a number of biologists see phosphorus as an (ultimate) limiting factor for agriculture.

Also, phosphorus is a limiting factor for some ecosystems.


Phosphorus consumption: I did a detailed study of ethanol energy ratios and learned some very interesting things. While I focused on nitrogen, not phosphorous, some of the same lessons still apply. Current energy ratios for ethanol are a crock. Not that they don't reflect current practice. The problem is that we ignored Einstein's advice

We can't solve problems by using the same kind of thinking we used when we created them.

A quote that should be familiar to people here as it is one of the quotes in the oil drums quote of the day rotation. The excessive energy use in producing ethanol does not come from tractors (which, used efficiently with existing technology, need only about 2% of the energy produced). It comes from fertilizer and pesticide use and not using solar energy, biomass, or other non-fossil sources for distillation. And this is mostly unnecessary. We use lots of nitrogen fertilizer but ethanol contains no nitrogen. While nitrogen can be extracted from the air using appropriate winter cover crops, co-planting, or rotation, and phosphorous cannot, many of the lessons appear to apply to phosphorous as well as the loss mechanisms are the same except for one which does not apply to phosphorous:

Where does it go:

  • Runoff - Fix by proper grading of the land, biochar (which helps
    save runoff), and not applying to the fertilizer in excess
    quantities or on the surface.
  • soil erosion - pretty much the same as runoff.
  • Vaporization from the soil - minimized by better practices. Does not apply to phosphorous
  • leaching: trickling down to the water table - minimize by
    use of biochar and others that help retain soil in the ground. May also be able to
    recover some from groundwater. Also, plants with deeper roots
    might help fix nutrients that are lost to other plants.
  • shipped off the farm in intermediate products (corn, etc.) and not
  • food byproducts for humans and animals - this is a cost of food
    production and not ethanol production and can ultimately be

As far as mineral nutrients are concerned, a general rule for humans and animals is what goes in the front end comes out the back end (see humanure comments above). Some goes into meat, much of which then comes out the back end of a human. And some goes into our corpses - which do not have to be marinated in formaldehyde and lost to the ecosystem. Ashes can be scattered over farm land. Food waste which is landfilled instead of composted (or composed is wasted on lawns) is a loss. Biological materials, and the nutrients they contained, need to be returned to the soil.

Ethanol doesn't contain phosphorous, either, but biodiesel (phospholipids) and food do. Phosphorous in biodiesel might be lost to the atmosphere when burned. Apparently, phosphorus content of biodiesel is pretty low (around 1ppm); this may be because it is removed in the degumming step. Ethanol has the advantage that it contains nothing but carbon, hydrogen, and oxygen which are all derived from CO2 from the air and water - there are no trace elements except as impurities. The same should be true of biodiesel as well, though the purification process may not be as good as the distillation used in making ethanol.

Much of the wasted phosphorous probably ultimately ends up in the oceans. Desalination or uranium extraction from seawater processes could possibly recover some.

Ultimately, all the nutrients plants need to grow are present in soil, air, and water as plants have grown almost anywhere there is water for millions of years without our help. Phosphorous may not be abundant in high concentrations where it can be mined but it must be abundant in trace amounts in the earth's outer crust from which soil is derived. So the trick is to not deplete our soil faster than it is replenished. Mother nature did it for millions of years and we need to follow her lead.

The type of curve fitting analyses being used probably does not apply to phosphorous because a large amount of depletion from centuries of farming had to be corrected. In modern Western agriculture phosphorous is over applied (in excess of crop removal) to maximize yields and to build up the soil reserve. Also some phosphorous reacts with soil minerals and becomes relatively unavailable. Because soil phosphorous has been built up to very high levels in some soils it is now common to test either the soil or leaves from crops to determine phosphorous and potassium fertilizer recommendations. However, there is still a significant percentage cropland in the US and Europe that has low to moderate levels of P and K.

I have no reason to doubt the US Geological Survey’s estimate of 120 years of phosphorous reserves at current consumption. The USGS estimates there are another 200 years of lower grade resources which will be much more expensive to produce. An important question is “are current rates sufficient in light of the fact that one third of the world’s population does not get enough to eat”?

There is no doubt as to the seriousness of running out of phosphorous. The current world population cannot be supported without continuous application of phosphorous fertilizers.

Currently we waste phosphorous in the developed countries by not returning animal and human urine and feces to the soil. Also, we send phosphorous to landfills in the form of bones, which are approximately 10% phosphate.

The human population responded to increased phosphorous in the same manner as algae does to agricultural run-off, that is, we greatly expanded our population. Our population was greatly constrained for millennia after reaching a plateau following the practice of farming by low crop yields due to soil depletion.

A famous case study is the Cullars Rotation at Auburn University, Alabama, USA that tracked yields of various major crops with various combinations of N, P, K and lime or no treatment since 1911. This study clearly demonstrates that yields will decline to nearly zero after a few decades of cropping without replacing nutrients. Of course, some soils are naturally high in fertility, especially in arid regions or rocky soils that can weather and release nutrients. Volcanic soils tend to be especially rich.

The practice of letting fields lie fallow allows cover crops to gather minerals from weathering. Letting fields lie fallow was known in ancient times and is mentioned by Julius Caesar in The Conquest of Gaul. Caesar also mentions certain tribes that invaded their neighbors in order to take their more fertile cropland. Footnotes of the translation I read cited probable crop yields, which were mere fractions of what we achieve today, perhaps 15 to 20%. That Caesar would have to eventually kill an estimated 1,000,000 barbarians in the region in order to keep the peace speaks as to their desperation.

1. "The phosphorus content of our land, following generations of cultivation, has greatly diminished," President Roosevelt said. "It needs replenishing. I cannot over-emphasize the importance of phosphorus not only to agriculture and soil conservation but also the physical health and economic security of the people of the nation. Many of our soil deposits are deficient in phosphorus, thus causing low yield and poor quality of crops and pastures…"

2. International Plant Nutrition Institute

A relevant question would be whether the phosphorus production peak is symmetrical or not. This is not clear to me, and seems like a strange assumption that is made with regards to many oil peaking theories as well. Occam would not be pleased.