Peak Phosphorus
Posted by Prof. Goose on August 17, 2007 - 10:00am
Topic: Alternative energy
Tags: agriculture, depletion, hubbert linearization, original, phosphorus, recycling [list all tags]
This is a guest post by Patrick Déry and Bart Anderson. Patrick Déry is a physicist, energy, agriculture and environment analyst and consultant in Quebec, Canada. Bart Anderson is a former reporter, teacher and technical writer; he currently is co-editor of Energy Bulletin.
Peak oil has made us aware that many of the resources on which civilization depends are limited.
M. King Hubbert, a geophysicist for Shell Oil, found that oil production over time followed a curve that was roughly bell-shaped. He correctly predicted that oil production in the lower 48 states would peak in 1970. Other analysts following Hubbert's methods are predicting a peak in oil production early this century.
The depletion analysis pioneered by Hubbert can be applied to other non-renewable resources. Analysts have looked at peak production for resouces such as natural gas, coal and uranium.
In this paper, Patrick Déry applies Hubbert's methods to a very special non-renewable resource - phosphorus - a nutrient essential for agriculture.
In the literature, estimates before we "run out" of phosphorus range from 50 to 130 years. This date is conveniently far enough in the future so that immediate action does not seem necessary. However, as we know from peak oil analysis, trouble begins not when we "run out" of a resource, but when production peaks. From that point onward, the resource becomes more difficult to extract and more expensive.
Physicist Déry applied the technique of Hubbert Linearization to data available from the United States Geological Survey (USGS)[1] to phosphorus production in the following:
He tested Hubbert Linearization first on data from Nauru to see whether he could have predicted the year of its peak phosphate production in 1973. Satisfied with the results, he applied the method to United States and the world. He estimates that U.S. peak phosphorus occurred in 1988 and for the world in 1989.
Phosphorus (chemical symbol P) is an element necessary for life. Because phosphorus is highly reactive, it does not naturally occur as a free element, but is instead bound up in phosphates. Phosphates typically occur in inorganic rocks.
As farmers and gardeners know, phosphorus is one of the three major nutrients required for plant growth: nitrogen (N), phosphorus (P) and potassium (K). Fertilizers are labelled for the amount of N-P-K they contain (for example 10-10-10).
Most phosphorus is obtained from mining phosphate rock. Crude phosphate is now used in organic farming, whereas chemically treated forms such as superphosphate, triple superphosphate, or ammonium phosphates are used in non-organic farming.
Philip H. Abelson writes in Science:
More information:
In his frightening book Eating Fossil Fuels [3], Dale Allen Pfeiffer shows that conventional agriculture is as oil-addicted as the rest of society. A decline in oil production raises questions about how we will feed ourselves.
In the same way, agriculture is addicted to mined phosphates and would be threatened by a peak in phosphate production. As the U.S. Geological Survey (USGS) wrote in summary on phosphates (PDF):
Tools that have been used for analyzing peak oil can be applied to phosphate production. As we will see, phosphorus production follows a more-or-less bell-shaped (parabolic) curve, just as oil production does.
Hubbert's parabolic curve is based on a differential equation explained by Stuart Staniford:
Hubbert Linearization was first developed by geologist Kenneth Deffeyes, an associate of M. King Hubbert. The technique has been discussed by analysts such as Stuart Staniford, Jeffrey J. Brown and Robert Rapier at The Oil Drum. The term Hubbert Linearization was coined by Stuart Staniford.
In Hubert Linearization, the production data from the bell-shaped Hubbert curve is plotted as a line. On the graph:
This paper purposely minimizes the math so as to reach a wide audience; however, much more detail on H-L is available online. For example:
For the purposes of this paper, Déry looked at data for commercial phosphate (26-34% of P2O5). Other reserves of rock phosphate with lower concentrations of P2O5 do exist, but, just as with tar sand for oil production, they are more costly to exploit - economically, energetically and environmentally.
Using data from United States Geological Survey (rock phosphate production historical data series), Déry did a Hubbert Linearization for United States and for world rock phosphate production.
Results were stunning. The theoretical logistic curve fits almost perfectly with the real data curve. Déry found that we have already passed the phosphate peak for the United States (1988) and for the world (1989).
However those results seemed too perfect, so Déry tested the method on an almost depleted region of rock phosphate production, a case similar to that of United Stated for oil. A small island in the South Pacific called Nauru appeared to be an ideal case. The Nauru Island is 21 km² with only one economic resource (besides being a fiscal paradise!): rock phosphate. This resource has been almost entirely depleted since 2005.
According to the CIA World Factbook:
Plotting the rise and fall of rock phosphate production on Nauru yields this graph:
To begin with, Déry made a Hubbert Linearization with the stabilised data (linear trends since 1959) and found an Ultimate Recovery Reserves (URR) equivalent of 77 000 kT and a peak of rock phosphate production in 1973.
Looking at the results, he asked himself a question: would it be possible to predict the URR and the profile of future production just before the peak or just after? To get an answer, he used the data from 1959 to 1970 (just before peak) and 1959 to 1980 (just after peak). The results were :
If we calculate to obtain production curves for all these scenarios and put them on the same graph with real data, we obtain:
We see that the Hubbert Linearization just before peak, with this data set, exaggerated the URR (+26%) but the peak date (1978) was not so different from the real peak date (1973). It’s the contrary for a H-L just after peak: the URR is slightly smaller (-6,5%) and the peak date is earlier (1971).
The case of the United States is worth investigating since it is the "world’s leading consumer, producer, and supplier of phosphate fertilizers," according to the USGS.
Plotting phosphate production for the United States, we obtain:
Using data from 1982 to 2004, we find an URR of 2850 MT.
Calculating the production curve and plotting them with the real data gives us an estimated peak of 1988.
Plotting phosphate production for the world as a whole we obtain:
Using data from 1968 to 2005 reveals an URR of 8000 MT for the world as whole.
Calculating the production curve and plotting them with the real data:
We can see from the preceding graph that we are probably on a world decline of rock phosphate production.
Conventional agriculture uses vast amounts of oil and gas to produce food. We have just to plot data of world population versus world oil production to see the strong correlation between them.
But oil production is not the whole story. Nutrients like nitrogen and phosphorus were also required for the “Green Revolution”.
Nitrogen is present in large quantity in the atmosphere (78% of its composition). The Haber-Bosch process for obtaining nitrogen uses one percent of all energy consumed by humans [5]. Nitrogen can also be fixed in the soil using micro-organisms such as rhizobium and azotobacters. If there is sufficient energy, nitrogen will be available.
Phosphorus may be the real bottleneck of agriculture. [6]
Population growth was only possible because we found phosphorus deposits and cheap energy to extract, transform and transport it to farms. When we plot data of world population versus world phosphate production, we find a significant correlation.
What does this correlation mean? Even if we find a real substitute for fossil fuels, it will be impossible to maintain population growth because phosphate deposits are probably in decline. It will be impossible to maintain an agriculture without recycling nutrients.
In some ways, the problem of peak phosphorus is more difficult than peak oil. Energy sources other than oil are available, though they all have their own shortcomings. In addition, the sun provides a steady input of energy.
Unlike fossil fuels, phosphorus can be recycled. However if we waste phosphorus, we cannot replace it by any other source. Currently we are running through the limited supplies of concentrated phosphates. Phosphate fertilizer is often applied carelessly, leading to waste and pollution. Food from agriculture goes to consumers and animals, who excrete most of the phosphorus. The phosphorus in sewage mainly goes to sea or is otherwise dispersed.
The key response to a phosphorus peak is to re-create a cycle of nutrients. F.H. King in his classic Farmers of Forty Centuries: Organic Farming in China, Korea and Japan [4] describes how returning human and animal manure to the soil enabled Asian agriculture to continue to be productive for millenia.
Sewage sludge is one method now used for returning nutrients to agriculture, although there are safety concerns about the process. Other possibilities include:
(1) United States Geological Survey (USGS). Phosphate Rock Statistics and Information. Last updated 2007. Multiple documents.
(2) Abelson, Philip H. "A Potential Phosphate Crisis." Science. 26 March 1999: Vol. 283. no. 5410, p. 2015.
(3) Pfeiffer, D.A. Eating fossil fuels, oil, food and the coming crisis in agriculture, New Society Publisher, 2006.
(4) F.H. King. Farmers of Forty Centuries: Organic Farming in China, Korea and Japan , Dover Publications, NY, 1911 (ed. 2004)
(5) Smith, Barry E. “Nitrogenase Reveals Its Inner Secrets”, Science, 6 September 2002: Vol. 297. no. 5587, pp. 1654 – 1655, www.sciencemag.org/cgi/content/full/297/5587/1654
(6) Conrad, Jim. “A bottleneck in nature”, Backyard Nature, www.backyardnature.net/phosphor.htm
(7) Jenkins, J.C. The Humanure Handbook, Jenkins Publishing, 1994
(8) Anderson, Joe. "Toilets vs. Life as We Know It." Energy Bulletin. September 2004.
(9) EcoSanRes (Stockholm Envrionment Institute). Closing the Loop on Phosphorus (PDF). April 2005.
(10) McInerney, Su. "A blooming waste," University of Technology Sydney (Marketing and Communication Unit). November/December 2006. [Short article about phosphate researcher Dana Cordell; see following entry].
(11) Cordell, Dana. Urine Diversion and Reuse in Australia: A homeless paradigm or sustainable solution for the future? (Master's Thesis). Department of Water & Environmental Studies, Linköping University. (PDF version.) February 2006.
Déry, Patrick, « Pérenniser l’agriculture » Mémoire pour la Commission sur l’avenir de l’agriculture du Québec, avril 2007, www.caaaq.gouv.qc.ca/userfiles/File/MEMOIRE(1)/02-07-Saguenay-Dery,Patrick.pdf (in french only)
Brown, A. Duncan. Feed or Feedback: Agriculture, Population Dynamics and the State of the Planet, International Books, 2003.
Gunther, Folke. Vulnerability in Agriculture: Energy Use, Structure and Energy Futures, presented at the INES conference, THK, Stockholm, 2000.
B.Gumbo, H.H.G. Savenije and P.Kelderman. 2002. Ecologising Societal Metabolism: the Case of Phosphorus. In: Proc 3rd Int Conf Environmental Management. 27-30 August 2002.
Steen, P. 1998, Phosphorus Availability in the 21st Century: Management of a Non Renewable Resource. Phosphorus and Potassium.
~~~~~~~~~~~~~~~ Editorial Notes ~~~~~~~~~~~~~~~~~~~
Patrick Déry is a "physicist, energy, agriculture and environment analyst and consultant in Quebec, Canada."
Bart Anderson is a former reporter, teacher and technical writer. He currently is co-editor of Energy Bulletin.
Patrick sent the original article to Energy Bulletin in April. I had never seen anyone apply the concepts of peak and Hubbert Linearization to phosphorus. Even though I had known intellectually that phosphorus supplies were limited, it wasn't until I read Patrick's paper that I realized how urgent the situation is.
To make Patrick's ideas more widely accessible, I added background information and did some wordsmithing, but all the original ideas are his.
For more background, see Peak phosphorus: readings (Energy Bulletin).
-BA
Physicist Déry applied the technique of Hubbert Linearization to data available from the United States Geological Survey (USGS)[1] to phosphorus production in the following:
- The small Pacific island nation of Nauru, a former phosphate exporter.
- The United States, a major phosphate producer.
- The world.
He tested Hubbert Linearization first on data from Nauru to see whether he could have predicted the year of its peak phosphate production in 1973. Satisfied with the results, he applied the method to United States and the world. He estimates that U.S. peak phosphorus occurred in 1988 and for the world in 1989.
Phosphorus - its role and nature
Phosphorus (chemical symbol P) is an element necessary for life. Because phosphorus is highly reactive, it does not naturally occur as a free element, but is instead bound up in phosphates. Phosphates typically occur in inorganic rocks.
As farmers and gardeners know, phosphorus is one of the three major nutrients required for plant growth: nitrogen (N), phosphorus (P) and potassium (K). Fertilizers are labelled for the amount of N-P-K they contain (for example 10-10-10).
Most phosphorus is obtained from mining phosphate rock. Crude phosphate is now used in organic farming, whereas chemically treated forms such as superphosphate, triple superphosphate, or ammonium phosphates are used in non-organic farming.
Philip H. Abelson writes in Science:
The current major use of phosphate is in fertilizers. Growing crops remove it and other nutrients from the soil... Most of the world's farms do not have or do not receive adequate amounts of phosphate. Feeding the world's increasing population will accelerate the rate of depletion of phosphate reserves.and
...resources are limited, and phosphate is being dissipated. Future generations ultimately will face problems in obtaining enough to exist.It is sobering to note that phosphorus is often a limiting nutrient in natural ecosystems. That is, the supply of available phosphorus limits the size of the population possible in those ecosystems.
More information:
- Understanding Phosphorus and its Use in Agriculture from the European Fertilizer Manufacturers Association.
- Phosphate Primer by Florida Institute of Phosphate Research.
Prospect of a Phosphorus Peak
In his frightening book Eating Fossil Fuels [3], Dale Allen Pfeiffer shows that conventional agriculture is as oil-addicted as the rest of society. A decline in oil production raises questions about how we will feed ourselves.
In the same way, agriculture is addicted to mined phosphates and would be threatened by a peak in phosphate production. As the U.S. Geological Survey (USGS) wrote in summary on phosphates (PDF):
There are no substitutes for phosphorus in agriculture.Fortunately, phosphorus - unlike oil - can be recycled. Responses to a phosphorus peak include re-creating a cycle of nutrients, for example, returning animal (including human) manure to cultivated soil as Asian people have done in the not-so-distant past [4].
Hubbert Linearization
Tools that have been used for analyzing peak oil can be applied to phosphate production. As we will see, phosphorus production follows a more-or-less bell-shaped (parabolic) curve, just as oil production does.
Hubbert's parabolic curve is based on a differential equation explained by Stuart Staniford:
The idea behind the equation is that early on, the oil industry grows exponentially - the annual increase in production is proportional to the total amount of knowledge of resources, oil field equipment, and skilled personnel, all of which are proportional to the size of the industry. ...To estimate future production and total production, some analysists have turned to the technique of Hubbert Linearization (H-L).
Later, however, the system begins to run into the finiteness of the resource - it gets harder and harder to get the last oil from the bottom of the depressurized fields, two miles down in the ocean, etc, etc.
Hubbert Linearization was first developed by geologist Kenneth Deffeyes, an associate of M. King Hubbert. The technique has been discussed by analysts such as Stuart Staniford, Jeffrey J. Brown and Robert Rapier at The Oil Drum. The term Hubbert Linearization was coined by Stuart Staniford.
In Hubert Linearization, the production data from the bell-shaped Hubbert curve is plotted as a line. On the graph:
the y-axis (vertical) is P/Q whereBy extending the line in the graph, one can estimate Ultimate Recoverable Reserves (URR) for the region (Qt).
P = annual production and
Q = total production to date
the x-axis (horizontal) is Q (total production to date).
This paper purposely minimizes the math so as to reach a wide audience; however, much more detail on H-L is available online. For example:
Hubbert Linearization (Wikipedia)
In Defense of the Hubbert Linearization Method
Another Way of Looking at CERA by Stuart Staniford
When Does Hubbert Linearization Work? by Stuart Staniford
Predicting the Past: The Hubbert Linearization by Robert Rapier (H-L skeptic)
Applying Hubbert Linearization to Phosphates
For the purposes of this paper, Déry looked at data for commercial phosphate (26-34% of P2O5). Other reserves of rock phosphate with lower concentrations of P2O5 do exist, but, just as with tar sand for oil production, they are more costly to exploit - economically, energetically and environmentally.
Using data from United States Geological Survey (rock phosphate production historical data series), Déry did a Hubbert Linearization for United States and for world rock phosphate production.
Results were stunning. The theoretical logistic curve fits almost perfectly with the real data curve. Déry found that we have already passed the phosphate peak for the United States (1988) and for the world (1989).
Nauru
However those results seemed too perfect, so Déry tested the method on an almost depleted region of rock phosphate production, a case similar to that of United Stated for oil. A small island in the South Pacific called Nauru appeared to be an ideal case. The Nauru Island is 21 km² with only one economic resource (besides being a fiscal paradise!): rock phosphate. This resource has been almost entirely depleted since 2005.
According to the CIA World Factbook:
...intensive phosphate mining during the past 90 years - mainly by a UK, Australia, and NZ consortium - has left the central 90% of Nauru a wasteland and threatens limited remaining land resources
Plotting the rise and fall of rock phosphate production on Nauru yields this graph:
To begin with, Déry made a Hubbert Linearization with the stabilised data (linear trends since 1959) and found an Ultimate Recovery Reserves (URR) equivalent of 77 000 kT and a peak of rock phosphate production in 1973.
Looking at the results, he asked himself a question: would it be possible to predict the URR and the profile of future production just before the peak or just after? To get an answer, he used the data from 1959 to 1970 (just before peak) and 1959 to 1980 (just after peak). The results were :
- Just before peak : URR = 97 000 kT; peak date: 1978
- Just after the peak : URR = 72 000 kT; peak date 1971
If we calculate to obtain production curves for all these scenarios and put them on the same graph with real data, we obtain:
We see that the Hubbert Linearization just before peak, with this data set, exaggerated the URR (+26%) but the peak date (1978) was not so different from the real peak date (1973). It’s the contrary for a H-L just after peak: the URR is slightly smaller (-6,5%) and the peak date is earlier (1971).
United States
The case of the United States is worth investigating since it is the "world’s leading consumer, producer, and supplier of phosphate fertilizers," according to the USGS.
Plotting phosphate production for the United States, we obtain:
Using data from 1982 to 2004, we find an URR of 2850 MT.
Calculating the production curve and plotting them with the real data gives us an estimated peak of 1988.
World production
Plotting phosphate production for the world as a whole we obtain:
Using data from 1968 to 2005 reveals an URR of 8000 MT for the world as whole.
Calculating the production curve and plotting them with the real data:
We can see from the preceding graph that we are probably on a world decline of rock phosphate production.
Population and Phosphorus
Conventional agriculture uses vast amounts of oil and gas to produce food. We have just to plot data of world population versus world oil production to see the strong correlation between them.
But oil production is not the whole story. Nutrients like nitrogen and phosphorus were also required for the “Green Revolution”.
Nitrogen is present in large quantity in the atmosphere (78% of its composition). The Haber-Bosch process for obtaining nitrogen uses one percent of all energy consumed by humans [5]. Nitrogen can also be fixed in the soil using micro-organisms such as rhizobium and azotobacters. If there is sufficient energy, nitrogen will be available.
Phosphorus may be the real bottleneck of agriculture. [6]
Population growth was only possible because we found phosphorus deposits and cheap energy to extract, transform and transport it to farms. When we plot data of world population versus world phosphate production, we find a significant correlation.
What does this correlation mean? Even if we find a real substitute for fossil fuels, it will be impossible to maintain population growth because phosphate deposits are probably in decline. It will be impossible to maintain an agriculture without recycling nutrients.
Responses to Peak Phosphorus
In some ways, the problem of peak phosphorus is more difficult than peak oil. Energy sources other than oil are available, though they all have their own shortcomings. In addition, the sun provides a steady input of energy.
Unlike fossil fuels, phosphorus can be recycled. However if we waste phosphorus, we cannot replace it by any other source. Currently we are running through the limited supplies of concentrated phosphates. Phosphate fertilizer is often applied carelessly, leading to waste and pollution. Food from agriculture goes to consumers and animals, who excrete most of the phosphorus. The phosphorus in sewage mainly goes to sea or is otherwise dispersed.
The key response to a phosphorus peak is to re-create a cycle of nutrients. F.H. King in his classic Farmers of Forty Centuries: Organic Farming in China, Korea and Japan [4] describes how returning human and animal manure to the soil enabled Asian agriculture to continue to be productive for millenia.
Sewage sludge is one method now used for returning nutrients to agriculture, although there are safety concerns about the process. Other possibilities include:
- Composting toilets and composting of waste [7, 8, 9]
- Urine diversion [10, 11]
- More efficient application of fertilizer
- Technological innovations [2].
References:
(1) United States Geological Survey (USGS). Phosphate Rock Statistics and Information. Last updated 2007. Multiple documents.
(2) Abelson, Philip H. "A Potential Phosphate Crisis." Science. 26 March 1999: Vol. 283. no. 5410, p. 2015.
(3) Pfeiffer, D.A. Eating fossil fuels, oil, food and the coming crisis in agriculture, New Society Publisher, 2006.
(4) F.H. King. Farmers of Forty Centuries: Organic Farming in China, Korea and Japan , Dover Publications, NY, 1911 (ed. 2004)
(5) Smith, Barry E. “Nitrogenase Reveals Its Inner Secrets”, Science, 6 September 2002: Vol. 297. no. 5587, pp. 1654 – 1655, www.sciencemag.org/cgi/content/full/297/5587/1654
(6) Conrad, Jim. “A bottleneck in nature”, Backyard Nature, www.backyardnature.net/phosphor.htm
(7) Jenkins, J.C. The Humanure Handbook, Jenkins Publishing, 1994
(8) Anderson, Joe. "Toilets vs. Life as We Know It." Energy Bulletin. September 2004.
(9) EcoSanRes (Stockholm Envrionment Institute). Closing the Loop on Phosphorus (PDF). April 2005.
(10) McInerney, Su. "A blooming waste," University of Technology Sydney (Marketing and Communication Unit). November/December 2006. [Short article about phosphate researcher Dana Cordell; see following entry].
(11) Cordell, Dana. Urine Diversion and Reuse in Australia: A homeless paradigm or sustainable solution for the future? (Master's Thesis). Department of Water & Environmental Studies, Linköping University. (PDF version.) February 2006.
Déry, Patrick, « Pérenniser l’agriculture » Mémoire pour la Commission sur l’avenir de l’agriculture du Québec, avril 2007, www.caaaq.gouv.qc.ca/userfiles/File/MEMOIRE(1)/02-07-Saguenay-Dery,Patrick.pdf (in french only)
Brown, A. Duncan. Feed or Feedback: Agriculture, Population Dynamics and the State of the Planet, International Books, 2003.
Gunther, Folke. Vulnerability in Agriculture: Energy Use, Structure and Energy Futures, presented at the INES conference, THK, Stockholm, 2000.
B.Gumbo, H.H.G. Savenije and P.Kelderman. 2002. Ecologising Societal Metabolism: the Case of Phosphorus. In: Proc 3rd Int Conf Environmental Management. 27-30 August 2002.
Steen, P. 1998, Phosphorus Availability in the 21st Century: Management of a Non Renewable Resource. Phosphorus and Potassium.
~~~~~~~~~~~~~~~ Editorial Notes ~~~~~~~~~~~~~~~~~~~
Patrick Déry is a "physicist, energy, agriculture and environment analyst and consultant in Quebec, Canada."
Bart Anderson is a former reporter, teacher and technical writer. He currently is co-editor of Energy Bulletin.
Patrick sent the original article to Energy Bulletin in April. I had never seen anyone apply the concepts of peak and Hubbert Linearization to phosphorus. Even though I had known intellectually that phosphorus supplies were limited, it wasn't until I read Patrick's paper that I realized how urgent the situation is.
To make Patrick's ideas more widely accessible, I added background information and did some wordsmithing, but all the original ideas are his.
For more background, see Peak phosphorus: readings (Energy Bulletin).
-BA
I guess I am uneasy with this analysis - unless you can show that mankind has searched most of the planet for more phosphorous and come up empty, then it seems entirely possible that current reserves are only limited because nobody has bothered to go out and look for more.
The curves show a plateau in total production, but is that because it gets harder and harder to find more phosphorous, or is it because improved agricultural techniques to minimize topsoil losses and to reduce nutrient runoff have reduced the demand for more phosphorous?
I share the same concerns. Do we have discovery data for phosphorous deposits? I was wondering if a discovery peak exists. The use of phosphorus has also been limited in certain country (ex: France) because of problems of eutrophication of water.
It seems intuitive that the phosphorus deposits have to be very easy to access for it to be profitable. Phosphate rock goes for around $30 per ton, while a barrel of oil is about $70 for 0.136 tons (or $500/ton). That must have some impact on how far and deep we will go to recover it ... at the present time.
I think you can rule that out, because the phosphorous is used by the plants to build themselves. It's a cycling element, not a catalyst, so it needs to be renewed after every harvest. A typical ecology keeps it local via dropping leaves, faeces and animal corpses. However, if you harvest and export it, it is necessary to supply new P from either a finite source (mineral deposits or the soil), or import it from elsewhere, preferably from those that consumed it in the first place, to close the cycle.
The very fact that runoff and rivers have problems with eutrophication suggests that excess phosphorous has been over-applied, and is washing into various waterways. As humans become smarter about preventing this, then demand for phosphorous would go down.
Eventually you would reach a theoretical point where the only phosphorous that is applied is used by the plants that are shipped out, but even then some of it is recoverable from sewage.
I think you are correct that farmers are becoming better at managing fertilizer application. Have world sales of phosphate decreased because of greater use efficiency, or are sales still rising with previously mined phosphates stores being depleted to compensate for lower extraction rates?
Another reason for run off problems, in addition to over application, could be the type of phosphate applied. I believe those superphosphate products have been manipulated to increase solubility and rapid availability to plants, but since the soils are mostly dead and organic matter levels are so low, any excess phosphate runs off fast.
Organic farmers use products that are less immediately available, have slow release properties, and therefore don't have these run off problems.
In areas with low soil PH, runoff is more unlikely. In soil conditions with a PH of say... under 5.3, P tends to bond with soil particles, more so in fine/clay soils which have more surface area per gram.
Liquid calcium or Lime will raise the PH and make the "P" water soluble again.
N,P, K & Fe are not water soluble at low PH. So the mechanism of runoff should be of low concern in soils with PH below 5.3 or so.
See: cation exchange capacity
Conveniently, Fertilizers lower the pH. If the pH goes below 4.5, then the plants suck up potential heavy metals (and I don't mean Black Sabbath). Below 3.5 pH, Aluminum becomes soluble and everything dies.
Expanding further, the fungus and bacteria association with the plant diminishes with these fertilizers (and much soil life is killed). The plants become bloated with water, which the herbivore insects take note and feast. Then the insecticides kill these "pests", but also the insect life in the soil. Without the insects to burrow into the soil, bringing down fungi, bacteria, and protozoa to the roots, the soil goes anaerobic.
Anaerobic soil means low pH, so even applications of Lime or whatnot don't work for long, as the nutrient plugs are already gone, the bacteria fight to keep a low pH, and nutrients wash out. Even worst are the blights that can now infiltrate an unprotected ecosystem (note fungi above).
http://soils.tfrec.wsu.edu/mg/chemical.htm
Aluminum starts becoming water soluble at 6.0 and lower.
PH of 4.5 is a bit too late, the nitrogen ammonia cycle is basically stopped at 4.5. At a PH of 5.6 nitrogen fixation by plants starts to be problematic.
Water logged soil is anaerobic, re: lack of oxygen.
Off topic but still an energy post. Both heavy duty and alkaline batteries use carbon and zinc electrodes but heavy duty batteries use an acid electrolyte and alkaline batteries use (you guessed it) potassium hydroxide. Alkaline batteries are mucho superior in every respect except initial cost and I never knew why until I saw your post. You do NOT want your electrode, in this case zinc, dissolving in your electrolyte.
Nickel Iron batteries, touted by one of us, last essentially forever because the electrodes are essentially insoluble in potassium hydroxide. They have other issues, but they last forever.
I shoulda known quoting from my Permaculture class. However, the pH and Aluminum problem is still around 3.5 pH when no plant can survive. The issue relates to the interaction between Phosphorus and Aluminum across a spectrum of pH.
http://www.plantphysiol.org/cgi/reprint/18/4/708.pdf
I'm sure there are other references out there.
Yes, water logged soil is indeed anaerobic. I'm trying not to write a book inside a comment, so have compressed the whole process of tilling, fertilizing, biocides, etc that comprise our conception of food "production" as fundamentally flawed and always ends in depleted soil and desertification.
PH of 4.5 is a bit too late
Let's not split hairs to fill in the 0.5 pH to go. It's out there, if you want to find a plant that "survives" it. However, below 3.5 is certainly a dead zone.
Stream of consciousness. Nobody thinks without phospourus. Aluminum causes phospourus to precipitate. Aluminum is implicated in Alzheimers.
Blood is a mild base. Unless you suffer from acidosis. CO2 makes carbonic acid. Therefore exercise is bad for you. Couch potatoes have the best brains on the planet.
Okay this all makes perfect sense, but then again I keep hearing about the enormous swine manure problem and how it poses such an extreme biohazard.
Is this due to a lack of proper resource management on the part of the pig farmers? Is swine manure a good source of phosphates?
There's a lot of phosphorous in pig manure. It limits the amount of manure you can apply to an acre which means you may not be able to apply enough to meet nitrogen requirements.
You can either top off the nitrogen with Haber-Bosch fertilizer or you can go to old-fashioned crop rotation using legumes like soybeans, clover or alfalfa.
I just wonder where all the sediment and animal wastes are disposed of ultimately. Certainly we're not supposed to dump them into lakes and rivers. How much phosphorus is in landfills of any type? Anyone know?
Manure is a good source of methane if digested anaerobically, and there has been noise about growing algae on sewage effluents for tertiary treatment (which includes phosphorus removal). Then you've got the people touting biofuel production from the algae. This looks like the better part of a cycle.
I'd like to know if the ash from gasified algae cake contains enough phosphorus and the like to be worth shipping. Does anyone have a chemical analysis of dried algae?
Actually shortages of key resources may crop up in unexpected places. One that I track informally is Tantalum. This is a rare-earth metal that is used in many electronic devices.
It's properties are what allows the high degree of miniaturization in items like cell phones. There are substitutes, but they all have drawbacks.
The supply of Tantalum is limited to begin with and their are continuing battles in the areas in Africa where it is mined over control of the resources. It is impractical to recycle it since the amount in each cell phone is insignificant, but the total over the billions of phones made and discarded adds up.
Personally I think the first choke point will be fresh water and arable land. To produce fresh water from non-potable sources (such as the sea) is very energy intensive and that gets us right back to the same place: energy use vs climate change vs "peak".
The whole idea of growth and unlimited consumption needs to be addressed, present trends are unsustainable.
The whole idea of growth and unlimited consumption needs to be addressed, present trends are unsustainable.
Potable water, Fossil Fuels, and Phosphorus are leading my list on 'society limiters' that there are no simple 'technoswaps' for. With the economic effects of the end of under priced energy being the 1st hit of many.
But hey, we've got plenty of hope, right you technofixers?
(listens to the sounds of crickets here on the high ground)
It is impractical to recycle it since the amount in each cell phone is insignificant, but the total over the billions of phones made and discarded adds up.
All depends on the price. Eventually you'd have people scrapping the capacitors off the boards for the Tantalum.
Tantalum capacitors have drawbacks too. In addition to being a blood metal. Large ceramic caps have superior electronic properties but will make your cellphone slightly bigger.
Actually minaturisation isnt all its cracked up to be. It's basically a marketing tool - except for missiles and satellites. If we didnt have small cell phones how bad would that be? [Hint: you wont catch me with one any size..]
People who HAVE to communicate could carry a backpack or whatever.
We can live without tantalum capacitors and resistors. Ceramics can be even smaller.
tantalum capacitors and resistors
Sure enough - tantalum is now to be found in (some) resistors.
I used to work for an air force contractor and I designed in big f--king ceramic capacitors everywhere because of reliability issues with tantalum. It might weigh an extra microgram but that's someone else's problem. When your cellphone goes dead, you just buy a new one. And you'll probably buy a new cellphone in three years even if you already own a perfectly good one.
Tantalums are polar which means off the bat the guys who took a three week course to be certified as the only people on base qualified to pick up a soldering iron will install it backwards. In a best case scenerio, I still have to spend a day writing a test plan explaining how some airforce schmuck can demonstrate that it is installed correctly. The testplan has to be approved by four levels of management, the QA manager, the air force, the safety committee, and the trilateral commission, save my immediate supervisor none of whom know which end of a diode is up. It then gets an official document number record from the person who does nothing but keep track of paperwork so that all the other documents can cross reference it by number. Tantalums will easily cost the air force an extra ten grand. And that's before someone figures out it is a strategic metal that only comes from Congo and asteroids.
Bart, Patrick, PG,
Thanks for an interesting post. Are reserve figures available? How do they compare with the Hubbert linearization?
So, all that phosphorous that goes into the seas stay on the water or go to the botton?
How easy would it be to recover it on any of those cases?
That is what really worries me. Any P that sinks into the deep sea is gone for an eternity. I hope the amount we dug up makes up for the amount we have been letting, and will be letting, to wash away.
Phosphorus in the ocean is available to sea life.
This is one reason why fish like salmon are so necessary. They go to the ocean as fry and return as adults, with a large body mass of phosphorus (and potash and calcium and nitrogen). Animals like bears take the nutrients out of the streams and return most of them to the land; if we tried, we could improve that process. We couldn't engineer a better aid to nutrient replenishment.
As long as it stays on the continental shelf, that's as good as on land. But the deep sea trenches are virtually bottomless, and much more prone to tectonic recycling, which puts it out of reach. Also, the amount of nutrients that run off are too much for ecosystems to absorb, except for a few short-lived algal blooms.
conncentrated phosphorus in the water run-offs ia also terrible for the ecosystem. The "dead zone' at the mouths of our major agricultural river systems is caused not only by nitrogen causing the algal blooms but by phosphorus. If you all will recall, thats why they took the phosphates out of detergent about 25 or 30 tears ago, and its also credited with changing the vegetation in the everglades downstream of the American Sugar fields.
There are some less concentrated forms of ruck phosphate though, and I'm thinking about green sand, which is called glauconite?(some real geologist, help!) and that's fairly common, but the phosphorus is much lower than phosphate rock.
The real problem is population overshoot. When I was born in 1951 the world had less than 1/3rd of its current population, about 2 billion people. If the populaion had stabalised at that level we would not have a detectable global warming problem yet, a peak in energy production yet, or farming practices killing the oceans and rivers.
Get a vasectomy or tubes tied after one child everybody. Bob Ebersole
This reminds me of a study done to determine how the northern plains rejuvenated after the ice age. It was assumed that buffalo poop was the main 'culprit' but it turns out that 85% of the poop on a given area comes from birds, those last of the 'extict' dinosaurs rather than land mammals. Bird poop and seed transport are all that is needed to restore or move a boundary on a rapid basis. I betcha ther's lots of phosphorus in birdshit. And if we stopped crapping in the rivers and ate local... maybe WE are at Hubbert's peak?
Salmon returning to rivers to spawn have grown in the ocean.
This returns nutrients to the land as the salmon die and are carried away from river banks by scavengers.
Migratory river eels in Europe do the same I suspect.
Some local officials around here are open to composting toilets, but laws haven't changed yet. Working on it.
I think it was Frederick Soddy who said "No phosphorus no thought."
Quote: Ohne Phosphor, Kein Gedanke
Without phosphorus, there would be no thoughts.
Originator: Attributed to Ludwig Buchner (1824-1899)
"The real problem is population overshoot. When I was born in 1951 the world had less than 1/3rd of its current population, about 2 billion people. If the populaion had stabalised at that level...."
So Oilmanbob, did you procreate more than the authorize 2.1 times? I did. Unfortunately, our natural compulsions drive us inexorably toward overshoot.
A seductive explanation, but not necissarily true; While the earth clearly can't support population explosion forever, its not obvious that 2 billion is supportable forever and seven billion is far to much.
if you are so inclined....
http://science.reddit.com/info/2g3n7/comments
http://slashdot.org/firehose
This is an incredibly interesting article not for its analyses of phosphorous but more for its analysis of Hubbert Linearization.
Dr. Déry did H-L on Phosphorous from a number of angles on the island of Nauru. The question that arises is whether the results tend to be similar with H-L analysis of various resources. Specifically, is it always true that an H-L analysis using data from before peak yields a higher URR and a later peak date.
I doubt that this is the true but if it was, it would certainly be relevant to our current H-L analysis of World Oil Production since we are very near the peak.
I would love to hear opinions from some of the contributors who are more familiar with the Hubbert Linearization methods.
Rick
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