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Fertilisers (24/02/22 20:12:52) Reply
    Macronutrients for plants are nitrogen (N), phosphorus(P) and potassium (K).Nitrogen is in unlimited supply as it is sourced from the air, containing IIRC 78.1 percent nitrogen as N2. Together with hydrogen from natural gas it is used for synthesis of ammonia by the Haber-Bosch process. Ammonia is burnt in air to nitrogen oxides and reacted with water into nitric acid, which then is neutralised with ammonia to form ammonium nitrate, or with calcium carbonate to form calcium nitrate. For other products, calcium phosphate is reacted with nitric acid, and potassium sulfate is added.

    The phosphate is sourced from various sources, at least one of which is politically contentious (Western Sahara).

    Potassium is sourced from Belarus,which is an increasing problem.

    https://www.yara.com/crop-nutrition/why-fertilizer/production-of-fertillizer/

    --

    Well. Phosphate and potassium, in the form that are used, are limited resources. Much of it endsin sewage and goes into the ocean, with minimal attempts at recovery.

    I'll see if I can research the topic more thoroughly.
e
Re: Fertilisers (25/02/22 10:25:39) Reply
    What I was just reading is that two thirds of ammonium nitrate globally is exported by Russia, which already started cutting the export a few months ago...
rf
Re: Re: Fertilisers (25/02/22 10:27:36) Reply
    https://www.spglobal.com/platts/en/market-insights/latest-news/agriculture/020222-russia-bans-ammonium-nitrate-exports-until-april-to-support-domestic-farmers

    "Support domestic farmers"...
rf
Re: Re: Re: Fertilisers (25/02/22 16:15:38) Reply
    Let'slook at the chemistry

    1 ammonium nitrate requires 6 hydrogens for synthesis (three for each nitrogen atom), so, ideally, each ammonium nitrate requires 1.5 methane (CH4).
    Ammonium nitrate: 2xN=28; 3xO=48, 4xH=4 makes 80.
    Methane: 4xH + C = 16. 1.5 methane makes 24.
    So 1 million tons ammonium nitrate translates into 300 000 tons natural gas. At least.
e
Re: Re: Re: Re: Fertilisers (25/02/22 21:12:35) Reply
    So now Yara has to pay top dollar for gas to make the ammonium nitrate.
e
Phosphorus (25/02/22 18:14:22) Reply
    Technologies exist

    "More than 70 full-scale P recovery plants are currently operating in Europe, North America, and East Asia. Basically, the P recovery technologies are (i) chemical Pi leaching from incinerated sludge ash, (ii) Pi salts precipitation, and (iii) struvite crystallization after anaerobic sludge digestion. Incinerated sludge ash having the high content of P is also used as a raw material for the manufacture of phosphoric acid in a wet acid process.

    P recovery practices are now expanding not only to the wastewater treatment sector but also to the manufacturing sector. In the manufacturing sector, Pi must be removed from wastewater to meet stringent effluent regulation in areas vulnerable to eutrophication. The recycling of recovered P products as a fertilizing material can save the costs of sludge disposal and leads to the significant reduction of plant operating expenses. P recovery is also practiced from solid waste streams such as animal manure and steelmaking slag. In East Asian countries, including China, Korea and Japan, steelmaking slag is one of the most important secondary P resources. Recovering P from steelmaking slag allows the rest to be reused as raw materials in blast furnaces. This has the enormous potential to improve the resource efficiency of steelmaking process.

    "

    https://iwa-network.org/phosphorus-recovery-and-reuse-from-wastewater/
e
Phospho Rus (25/02/22 21:15:26) Reply
    Apatite from Kola Peninsula, Murmansk Oblast, Russia

    https://www.mindat.org/locentries.php?m=29229&p=2666
e
Phosphorous fertilisers and cadmium (16/05/22 20:14:47) Reply
    This is a 2014 article. Before that there was a fertiliser scare about cadmium.


    "The main effect of Cd on human health is kidney disease, and although other adverse effects have been reported (e.g. pulmonary, cardiovascular, and musculoskeletal systems), controversy exists regarding their effects. The only known case of Cd toxicity (i.e. itai-itai disease) occurred with subsistence farmers in Japan growing rice on soils contaminated with industrial wastes. Cadmium behaviour in soil and its accumulation by crops is complicated. Numerous factors (e.g. soil pH, organic matter content, salinity, macro and micronutrient fertilizers, crops species and cultivar, and tillage) influence the bioavailability and uptake of Cd by crops. Because fertilization increases the risk of Cd transfer to the food chain, some governments have imposed limits restricting the Cd content of P fertilizers. However, scientific risk assessments have shown that P fertilizer containing Cd is safe and does not pose risk to human health."

    https://www.sciencedirect.com/science/article/pii/S1877705814011059

    In 2018

    "Fertilizers made from phosphate rock naturally contain cadmium that can accumulate in the soil; they are to blame for more than half of the heavy metal present in some agricultural soils. On average across Europe today, fertilizer contains about 32 milligrams of cadmium per kilogram (mg Cd/kg) of phosphorus, but the level can be as high as 200 mg Cd/kg, depending on where the phosphate rock is mined. Sedimentary phosphate rock found in northern Africa has naturally high cadmium levels, whereas so-called igneous rock found in Russian phosphate mines has much lower levels.

    Humans can get exposed to cadmium by ingesting crops that have taken up the metal from the soil. That doesn't appear to be a major problem in Europe; an EU-wide study published in 2015, for instance, showed that only 0.6% of 1271 nonsmoking women had an exposure higher than the "no-effect threshold.""

    (https://www.science.org/content/article/european-union-debates-controversial-plans-limit-cadmium-fertilizer)
e
Potassium: Reversible binding of ions (07/03/22 18:46:09) Reply
    It seems that natural zeolites

    https://www.mdpi.com/2076-3417/11/18/8660

    "Zeolites have a porous structure that can accommodate a wide variety of cations, such as Na+, K+, Ca2+, Mg2+ and others. These positive ions are rather loosely held and can readily be exchanged for others in a contact solution. Some of the more common mineral zeolites are analcime, chabazite, clinoptilolite, heulandite, natrolite, phillipsite, and stilbite. An example of the mineral formula of a zeolite is: Na2Al2Si3O10·2H2O, the formula for natrolite. Cation exchanged zeolites possess different acidity and catalyse different reactions.[7][8][9][non-primary source needed]

    Natural zeolites form where volcanic rocks and ash layers react with alkaline groundwater. Zeolites also crystallize in post-depositional environments over periods ranging from thousands to millions of years in shallow marine basins. Naturally occurring zeolites are rarely pure and are contaminated to varying degrees by other minerals, metals, quartz, or other zeolites. For this reason, naturally occurring zeolites are excluded from many important commercial applications where uniformity and purity are essential."

    (https://en.wikipedia.org/wiki/Zeolite)

    So zeolites are candidates for potassium recovery from sewage and seawater. But from there wehave a long and thorny road in technology development: How is recovery of the salt to be done? How is the concentrated solution going to be made in an energy-responsible way? How is fouling of the absorbent by algae andbacteria to be avoided? What is to be done with end-of-useful-life-material? Landfill is not an option.
e
Sustainability of a private economy (09/03/22 19:32:00) Reply
    In my petty burgeois world sustainability is a possibility if the family expenses in the long term are lower than the family income. Loans, mortgages - for sure. For house. For cars? I keep my cars for so long that I can buy a new one with savings when the old one dies.

    So - with agriculture: Today's mineral fertiliser use is unsustainable because it relies on tapping fossil nonrenewable resources of phosphate and potassium. Nitrogen is another matter - but we now see that the Oslo fjord is dying, presumably because of too high availability of nitrogen.

    And what do we know of the environmental consequences of metformin
    https://en.wikipedia.org/wiki/Metformin
    for a world population steadily getting fatter?
e
If the economy is unbalanced, it is unsustainable. (09/03/22 21:20:32) Reply
    So - either demand must go down, or there must be a mix of recycled material andnew material from a renewable source -read seawater. Only seawater is big enough.

    But will recycling and seawater be able to sustain all those billion people?Or must we simply overrun the religious reactionaries who are banning contraceptives and killing to hinder abortions?
e
Population planning and family planning and food (12/03/22 09:13:30) Reply
    At one level of population Earth will be on a point of no return - from loss of biodiversity, sea level rise, food scarcity from lack of fertiliser and loss of arable land to deserts, roads and buildings, and reactionary undereducation which cripples the mind and sabotages constructive developments.

    So - how much recycled or sustainably acquired fertilizer minerals can we produce? So far it is only manure, which was insufficient even 150 years ago.

    So better get started - either with phosphate and potassium recovery - or with worldwide contraception efforts. Ideally both.
e
Cycling of crops as a method of nitrogen enrichment of soil: Yes. What more? (12/05/22 07:31:15) Reply
    We have known for ages that peas, clover, beans and related plants have have bacteria that can fetch nitrogen from the air and incorporate it into useful chemicals like amino acids and B vitamins - thiamine, folate, biotin and others. Now, suddenly, I stumbled upon information that insects too have nitrogen-fixating bacteria, either in the gut, or even inside of cells. It has been found for aphids, termites and cockroaches, which live on nitrogen-free nutrients.

    So we have protein foodstuffs that do not need nitrogen fertiliser. To me that is sensational.

    A teaser (2015):

    https://www.researchgate.net/publication/272815297_N_Fixation_in_Insects_Its_Potential_Contribution_to_N_Cycling_in_Ecosystems_and_Insect_Biomass
e
Food for the belly - and food for thought (16/05/22 19:33:48) Reply
    #I think it could be plausibly argued that changes of diet are more important than changes of dynasty or even of religion. The Great War, for instance, could never have happened if tinned food had not been invented. And the history of the past four hundred years in England would have been immensely different if it had not been for the introduction of root-crops and various other vegetables at the end of the Middle Ages, and a little later the introduction of non-alcoholic drinks (tea, coffee, cocoa) and also distilled liquors to which the beer-drinking English were not accustomed. Yet it is curious how seldom the all importance of food is recognized. You see statues everywhere of politicians, poets, bishops, but none to cooks or bacon-curers or market-gardeners’#


    (https://orwellsociety.com/food-for-thought-i/)

    Ah, food.
e
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