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As Rock Phosphate Runs Out, What is More Important – Food Crops or Fuel Crops?

By Professor Chris Rhodes | Thu, 21 June 2012 21:41 | 3

World rock phosphate production is set to peak by 2030. Since the material provides fertilizer for agriculture, the consequences are likely to be severe, and worsened by the increased production of biofuels, including those from algae.


The depletion of world rock phosphate reserves will restrict the amount of food that can be grown across the world, a situation that can only be compounded by the production of biofuels, including the potential large-scale generation of biodiesel from algae. The world population has risen to its present number of 7 billion in consequence of cheap fertilizers, pesticides and energy sources, particularly oil. Almost all modern farming has been engineered to depend on phosphate fertilizers, and those made from natural gas, e.g. ammonium nitrate, and on oil to run farm machinery and to distribute the final produce. A peak in worldwide production of rock phosphate is expected by 2030, which lends fears over how much food the world will be able to grow in the future, against a rising number of mouths to feed. Consensus of opinion is that we are close to the peak in world oil production too. Phosphorus is an essential element in all living things, along with nitrogen and potassium. These are known collectively as, P, N, K, to describe micronutrients that drive growth in all plants and animal species, including humans. Global demand for phosphate rock is predicted to rise at 2.3% per year, but this is likely to increase in order to produce crops for biofuel production. As a rider to this, if the transition is made to cellulosic ethanol production, more phosphorus will be required still since there is less of the plant (the “chaff”) available to return as plant rubble after the harvest, which is a traditional and natural provider of K and P to the soil.

World rock phosphate production amounts to around 140 million tonnes. In comparison, we would need 352 million tonnes of the mineral to grow sufficient algae to replace all the oil-derived fuels used in the world. The US produces less than 40 million tonnes of rock phosphate annually, but to become self-sufficient in algal diesel would require around 88 million tonnes of the mineral. Hence, for the US, security of fuel supply could not be met by algae-to-diesel production using even all its indigenous rock phosphate output, and significant further imports would be needed. This is in addition to the amount of the mineral necessary to maintain existing agriculture. In principle, phosphate could be recycled from one batch of algae to the next, but how exactly this might be done remains a matter of some deliberation. e.g. The algae could be dried and burned, and the phosphate extracted from the resulting “ash”, or the algae could be converted to methane in a biodigester, releasing phosphate in the process. Clearly there are engineering and energy costs attendant to any and all such schemes and none has been adopted as yet.


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12 Comments on "As Rock Phosphate Runs Out, What is More Important – Food Crops or Fuel Crops?"

  1. BillT on Sat, 23rd Jun 2012 1:18 am 

    Only a fool would say that fuel is more important, but the world seems to be full of them at this time.

  2. Newfie on Sat, 23rd Jun 2012 2:00 am 

    BillT for President!

  3. MrEnergyCzar on Sat, 23rd Jun 2012 3:12 am 

    Buy Potash (POT) stock…takes oil to mine it..


  4. Harquebus on Sat, 23rd Jun 2012 4:27 am 

    Who’s worried about 2030. There won’t as many of us as there are today.

  5. Norm on Sat, 23rd Jun 2012 5:17 am 

    Well, there’s probably some solutions to the problem, just that society doesn’t want to pursue the solutions. In this case, more than likely, separate processing of urine vs other sewage would probably yield a huge amount of the crop fertilizers via urine. I think some of the ultra-liberals are advocating that already. But then you’d need a more complicated sewer system. Perhaps a good place to start would be larger public restrooms, truck stops etc where the stuff could be bottled & sent to factories separate from the other sewage.

    On the other hand, why solve the problem at all, if you can have societal breakdown & armageddon instead…. clearly thats preferable to solving the problem.

  6. BillT on Sat, 23rd Jun 2012 5:55 am 

    Actually, Norm, you are correct. China kept their fields fertile for centuries with the recycling of feces and urine even to the point of hauling it from the cities back to the farms. It was a profitable business.

    However, the stuff in those things today would make toxic buildup a problem. All of the metals and medicines we ingest and inhale would be passed into the excrement and then the plants would pick it up an send it back to us in the veggies. Maybe we would all be on a carrot high or glow in the dark? ^_^

    But you are correct. War is much more profitable than human manure.

  7. Stephen on Sat, 23rd Jun 2012 7:09 am 

    I think we will have to have societal forums and face some tough decisions, and if the human race wants to survive and thrive, they will have to choose a path that puts survival, sustainability, etc ahead of corporate profits and economic growth.

  8. Grover Lembeck on Sat, 23rd Jun 2012 7:35 am 

    I have read “farmers of 40 centuries”, and practice some of the ideas myself. I think that as far as the average American goes, BillT is unfortunately completely right. Even people I meet who are very health conscious are still ingesting massive amounts of really toxic crap. And crapping it right back out.

    It takes a lot of effort to make sure you are clean enough to be producing fertilizer. It is worth it, because you will feel better. And a system like imperial China’s is inevitable, if there is to be a human civilization long term.

  9. Rick on Sun, 24th Jun 2012 12:26 am 

    Most are correct here. But, I’ll make this real simple — “As Rock Phosphate Runs Out” Why too many fucking people. That’s the root cause to all world problems. BTW, I have NO kids.

    Small scale organic farming will be the future business. You can feed 100 people on 2.5 acres, managed by one person.

  10. BillT on Sun, 24th Jun 2012 1:07 am 

    Rick, I would be interested in seeing how you are going to do that. I seem to have read many places that a hectare will support about 10-15 max, depending on the climate.

    Keep in mind that it is not just food, but that land has to raise the fibers for clothes and wood for heat (winter) and cooking. Your clothes will be 100% cotton or wool or linen, not blends of oil and cotton. Your cooking fuel will grow on trees, not be pumped from the ground. Perhaps in perfect conditions, you could grow 3 crops of rice per year in a tropical climate…if you have the water.

  11. Terry Stuart on Sun, 24th Jun 2012 5:02 am 

    There is a urine separating plant in Vienna Austria already. It is part of the city sewage treament plant. None of this phsophorous that has been mined and will be mined has left the earth to my knowledge, rather it is simply a case of gathering it up and using it.

    Surprised you have not thought about using it for your home gardens—mix with H20—do not apply it directly to the plants. Reason I am surprised is with all of the rhetoric going on here, I would have to think you would all have home gardens and home grown urine you can begin applying today. As for the feces–not sure how much phosphorous it contains? Having spent time in rural China—boil everything if you are going to eat feces grown vegetables.

  12. BillT on Sun, 24th Jun 2012 11:30 am 

    Your urine contains all the metals, meds, chemicals, and, yes, even phosphorus, nitrogen, etc. The problem is the excess lead, mercury,and other remnants of what you breathe, eat or drink, what drugs you take or enjoy, and other variables. They would eventually build up in the soil until you were getting overloads or the plants would just not grow.

    As for boiling everything, maybe it would be a good idea with root vegetables, but if you scrub them well, raw is fine. Anything above ground would be safe, and probably the even more dangerous are the pesticides and herbicides used in commercial farming today in most of the world. If it kills plants and bugs, it is not doing you any good.

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