Once Again, Fertilizer is Not “Petroleum Based”

January 18th, 2009
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Green Gardens: What are ‘petroleum-based fertilizers’?

I keep hearing the term “petroleum based fertilizer” in the context of peak oil doom or other claims that we, as humans, are so dependent on oil that we can’t even eat without it because we grow our food with “petroleum based fertilizer.” I guess “We’re just too reliant on petroleum based fertilizer.” right?

No, not exactly. In general, fertilizer is not made from petroleum, period. The only exception to this might be the occasions where some very heavily contaminated oil comes out of the ground, and after a lot of purification, there’s a little bit of phosphorus left over as a byproduct. Occasionally such chemicals are derived from the stuff that’s extracted from crude, but this is not a major source. Other than that, oil is just plain not used to make fertilizer. It might be used to mine some of the minerals or transport the fertilizer, but this is pretty minor in the grand scheme of things.

For some further explanation, lets look at the primary types of fertilizer used in agriculture.

Fertilizer Types:

Potassium - Potassium comes from a variety of natural sources. One of the most common is potash, which can be found in large deposits in Canada, Russia, Europe and elsewhere. It can also be produced from seaweed or wood ash. Potassium can also be extracted from potassium salts which are commonly found in ancient lakebeds as well as in salt lakes such as the Dead Sea. Several other minerals also contain easily extractable potassium Significant amounts of potassium also can be found in seawater.

Phosphorus – Phosphorus is commonly produced from a number of phosphate minerals. phosphorus may also be extracted from processed biomass or from other sources including sea water, but the concentrations are too low to make it competitive with mineral-based phosphorus.

Nitrogen – Nitrogen fertalizers are created from the atmosphere through nitrogen fixation. This requires the use of hydrogen which is used in the Haber-Bosch process. Natural gas (methane) is by far the most common source of the hydrogen used in modern nitrogen fertalizer production, but it can be made from hydrogen derived from water and historically this has been done in a few instances when natural gas was not avalibale or because it was not feisable to purify the natural gas to remove sulfur, which can damage the catalyst used in the process.

Trace Mineral – A much less common fertalizer type, but in some cases areas may lack trace minerals such as iron or calcium, making this the limiting factor in the growth of plants. In such cases, mixtures of minerals may be added to suppliment the soil.

Now… where did you see oil in that list???


This entry was posted on Sunday, January 18th, 2009 at 11:37 pm and is filed under Agriculture, Bad Science, Culture, Good Science, Misc, Obfuscation. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.
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57 Responses to “Once Again, Fertilizer is Not “Petroleum Based””

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  1. 51
    Shafe Says:

            Jason Mckee said:

    That oil based fertilizer kills off all the healthy micro organisms in the soil, and depleats all the natural nutrients in the soil, so that you need to more of the fertilizer applied. It also destroys the ground water.

            Anon said:

    … not to mention actually understanding that fertiliser doesn’t deplete nutrients (it is after all used to add ones the soil is deficient in).

    The argument against synthetic fertilizers (at least in the context of lawn care) that seems to make the most sense is that such fertilizers supply nitrogen, phosphorus, and potassium as salts that cause the soil chemistry to become very distasteful to the critters that normally would be breaking down dead plant matter and aerating the soil. Add compost, mulch, grain meals, etc. to the exclusion of synthetic fertilizers, and you will promote such critter activity. Over time, they will improve your soil structure allowing for better moisture and nutrient retention. Now I can’t vouch for the accuracy of all that but there’s nothing on the face of it that strikes me as bunk, at least as far as lawns go. And if it can be said that farmers misuse or abuse fertilizers, how much more so do homeowners?

    I think the nutrient depleting argument is that the adding large amounts of N:P:K promotes growth, which creates demand for other nutrients that goes unmet if not also supplemented.


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  2. 52
    DV82XL Says:

            Shafe said:

    Now I can’t vouch for the accuracy of all that but there’s nothing on the face of it that strikes me as bunk, at least as far as lawns go. And if it can be said that farmers misuse or abuse fertilizers, how much more so do homeowners?

    Bottom line is that if you mono-crop any cultivar year over year, lawn grass included, you are begging for trouble.


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  3. 53
    Anon Says:

            Shafe said:

    The argument against synthetic fertilizers (at least in the context of lawn care) that seems to make the most sense is that such fertilizers supply nitrogen, phosphorus, and potassium as salts that cause the soil chemistry to become very distasteful to the critters that normally would be breaking down dead plant matter and aerating the soil.

    Natural fertilisers often use the same salts so that isn’t really an argument against synthetic fertilisers.

            Shafe said:

    I think the nutrient depleting argument is that the adding large amounts of N:P:K promotes growth, which creates demand for other nutrients that goes unmet if not also supplemented.

    It’s not like it’d be a problem for the synthetic fertilisers to add the other nutrients (though might be if you’re using natural fertilisers).

    Of course farmers should be regularly testing their soil to find out what they need to add, homeowners shouldn’t need to but the fertiliser sold to them should have all they need for normal soil type where they are.


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  4. 54
    Shafe Says:

            Anon said:

    Natural fertilisers often use the same salts so that isn’t really an argument against synthetic fertilisers.

    I’m not an expert on the topic, but one instance where that would not be the case is the use of soybean meal as a top treatment for lawn grass. The nitrogen in this fertilizer comes from the soy protein, not an ammonia salt. I don’t know what analogous methods might exist to provide P & K in a non-salt form if those salts are indeed problematic.

    I wouldn’t claim that just anything that says “organic” is automagically superior to synthetic fertilizers, but I do recognize that soil structure and soil biota are very important and that there’s more to assuring the long-term health of plants than simply supplying N, P, and K. If using leaf mold and grain meal instead of Scott’s Turfbuilder supports better soil health, then it’s worth considering.


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  5. 55
    kevin Says:

    Fixing nitrogen is from air is is high pressure process which requires a lot of energy. We now commonly use natural gas for the process because its cheaper although petroleum used to be the go to. It would be wrong to say fertilizer is BASED on any type of fuel. However the production process certainly REQUIRES a lot of fuel.


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  6. 56
    rb Says:

    Now… where did you see oil in that list???

    wrong question. Did not see oil .. but saw fossil fuels, primarily natural gas and sometimes coal where gas is less. They drive the haber-bosch process. Millions of years of stored solar energy used up in a flash to provide food for a few paltry generations.


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  7. 57
    Anon Says:

            rb said:

    wrong question. Did not see oil .. but saw fossil fuels, primarily natural gas and sometimes coal where gas is less. They drive the haber-bosch process. Millions of years of stored solar energy used up in a flash to provide food for a few paltry generations.

    But we’ve got enough Uranium and Thorium for a lot more generations.

    Seems to me you didn’t bother reading the post or any of the comments.


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