4 ms·

Another problem with hydroponics is its reliance on industrially-produced fertilizers, chiefly those containing nitrogen, phosphate, and potassium. The phosphat

Another problem with hydroponics is its reliance on industrially-produced fertilizers, chiefly those containing nitrogen, phosphate, and potassium. The phosphate and potassium parts of this equation are today mined from finite mineral deposits. Sooner or later these mines will close, and we'll have to close to the loop on phosphate and potassium (and molybdenum, calcium, etc.) production and consumption. How will hydroponic farmers adapt? Where will they economically obtain the necessary nutrient solution additives? Are there practical techniques to extract these nutrients from traditional sources, like urine or manure? The aspiring Mars colonist or hydroponic homesteader will need to figure this out, or return to traditional "regenerative" farming practices which compost biological waste and return all used-up nutrients and their constituent elements to the soil. And for someone like a Moon or Mars colonist, even regenerative farming isn't simple. Composting relies on bacteria to convert waste products like nitrogen-containing urea, whose nitrogen isn't bioavailable to plants, back into useful and bioavailable forms like ammonium. Keeping cultures of bacteria alive and healthy indefinitely will be essential to a colony's continued survival. Are there practical chemical processes to replace the function of these microbes, e.g. to convert urea to ammonia without urease enzymes? I don't know. Maybe someone with more knowledge can comment on this. I hope this problem can be solved. Hydroponics has many benefits, from dramatically lowered water consumption vs. soil-based agriculture, to higher yields driven by precisely-managed nutrient ratios. Spacefaring farmers will appreciate the weight saved by leaving all that excess water and soil on Earth. It'd be a shame to abandon this technology simply because we couldn't pivot away from fossil fertilizers.

moloch-hai 4y ago
Fortunately, there will not be Moon or Mars colonists, or colonies. Electric power to run the LEDs, if obtained from renewables, is protected from cost shocks, but such power might be more profitably sold at such times than used to drive LEDs and sell the produce.
- Grimburger 4y ago
  > there will not be Moon or Mars colonists, or colonies Bold statement, I'd be impressed if it holds up by mid-century.
  - imtringued 4y ago
    I hope you mean in 2072 and not in 2050 because Elon Musk promised to be on Mars by 2018.
  - moloch-hai 4y ago
    Try colonizing Antarctica first, on the dirt underneath the ice. If that turns out fantastically popular, do the sea floor. If that succeeds beyond reasonable expectation, you can try out life in an orbiting donut. If that takes off, a Mars colony might have a chance. SpaceX cans are woefully inadequate even to maintain a Mars outpost.
    - Grimburger 4y ago
      Ignoring the fact that multiple colonies already exist on Antarctica and living there is legally restricted to anyone without an army behind them, or that many people live under the ocean for large periods of time?
      - moloch-hai 4y ago
        There are exactly zero colonies on Antarctica. Literally all sites are 100% dependent on regular deliveries of all supplies, excepting air and maybe water, from overseas, with no plan for that ever to change, and no permanent residents. The usual term is "outpost", or for a larger operation, "base". There are no undersea outposts, even. Construction crews sometimes encamp for a few weeks for big hazard pay. There are two (count 'em!) low-orbital outposts that get literally all supplies except sunshine from the ground.
        Grimburger 4y ago
        The ISS is completely self-sufficient for water and air. No country on Earth is fully self-sufficient in what it uses and is dependent on supplies shipped to it from elsewhere. The word colony in the sense of space exploration and other extreme habitats means permanent occupation and exploitation of the resources there.
- farmaway 4y ago
  >Fortunately, there will not be Moon or Mars colonists, or colonies. Even if this pessimistic prediction comes true, the same nutrient-recycling solution could support human life in resource-poor regions on Earth, such as Antarctica or Detroit!
- linuxftw 4y ago
  People actually think we might colonize these places. Like, how are we going to send a bulldozer to the moon? How are we going to fuel it?
  - moloch-hai 4y ago
    They were told "we" would colonize, and believe it without thinking. The bigger question is how the liar benefits from the lie. Pumping stock value is the usual guess: (Tesla stock is only now starting to correct, and that largely because of the Twitter debacle.) The fusion-energy startup business runs this way.
  - LargoLasskhyfv 4y ago
    With big fucking rockets!
neuronexmachina 4y ago
> The phosphate and potassium parts of this equation are today mined from finite mineral deposits. Sooner or later these mines will close, and we'll have to close to the loop on phosphate and potassium (and molybdenum, calcium, etc.) production and consumption. This was honestly the first I've heard about concerns regarding phosphate and potassium supplies. After some quick googling, possible projections are 2030 for peak phosphate, 2057 for peak potassium: * https://en.wikipedia.org/wiki/Peak_phosphorus https://en.wikipedia.org/wiki/Peak_phosphorus (TIL a large majority of the world's phosphorus reserves are in Morocco) * Peak Potash study: https://www.sciencedirect.com/science/article/abs/pii/S0301420720308667 https://www.sciencedirect.com/science/article/abs/pii/S03014...
- farmaway 4y ago
  Didn't know peak phosphate was nearly upon us! On the bright side, technologies to recover phosphate via industrial-scale composting are already mature. My home state of Wisconsin leads the way on this, at least in the United States: https://en.wikipedia.org/wiki/Milorganite https://en.wikipedia.org/wiki/Milorganite >Milorganite is a brand of biosolids fertilizer produced by treating sewage sludge by the Milwaukee Metropolitan Sewerage District. The term is a portmanteau of the term Milwaukee Organic Nitrogen. The sewer system of the District collects municipal wastewater from the Milwaukee metropolitan area. After settling, wastewater is treated with microbes to break down organic matter at the Jones Island sewage treatment plant (also called "Water Reclamation Facility") in Milwaukee, Wisconsin. >The byproduct sewage sludge is produced. This is heat-dried with hot air in the range of 900–1,200 °F (482–649 °C), which heats the sewage sludge to at least 176 °F (80 °C) to kill pathogens. The material is then pelletized and marketed throughout the United States under the name Milorganite. The result is recycling of the nitrogen and phosphorus from the waste-stream as fertilizer. >The Milwaukee Metropolitan Sewerage District's Jones Island Plant had the largest wastewater treatment capacity of any in the world when constructed in 1925. It was the first plant in the United States to succeed in using the activated sludge treatment process to produce fertilizer. Potassium is excreted by humans mainly in urine, which is easy to recover. But NPK fertilizer is just one piece of the puzzle. AFAIK, plants require 17 essential micro- and macro-nutrients to grow [0]. I'm just a lay gardener, not a chemist nor research scientist, so I'm not sure how to approach recovering calcium, magnesium, sulfur, or metals like zinc and molybdenum for nutrient solution manufacture. That's the nice thing about composting for soil-based gardening; so long as the right microbes are there to make it bioavailable, all the elements you need are in the used-up biomatter. If it was eaten and not exhaled, sweated out, nor incorporated into the body, it'll be there in the waste stream. [0] https://www.researchgate.net/figure/There-are-17-essential-plant-nutrients-required-for-plant-growth_fig25_272818140 https://www.researchgate.net/figure/There-are-17-essential-p...
wskinner 4y ago
Do conventional farming methods also rely on NPK fertilizers? How do the fertilizer requirements of hydroponics differ from the fertilizer requirements of conventional?
- farmaway 4y ago
  Yes, they do. Modern industrial farming relies on the exact same fossil fertilizer inputs. When it comes to recycling phosphate etc., the rival to hydroponics and conventional farming is regenerative soil-based agriculture. The latter relies on composting and manuring to turn organic waste back into nutrient-rich soil. Among other functions, microbes in the soil and compost heaps break waste products like urea down into bioavailable forms like ammonium. Hydroponics generally doesn't involve composting and is by definition soil-free, so the plant's rhizosphere is more or less sterile: https://en.wikipedia.org/wiki/Rhizosphere https://en.wikipedia.org/wiki/Rhizosphere To farm plants without soil, they must be supplied with a water-based nutrient solution. The solution contains a precise mixture of all chemical substances a particular plant needs to grow. Yield efficiencies can be realized by carefully tailoring this mixture to each plant. The problem is where to source the ingredients once extracting them from mineral deposits turns uneconomical. Compost- and manure-amended soil theoretically has everything plants need, but that's not very useful for soil-free farming. The precise ratio of nutrients in a given patch of soil is also outside of the farmer's control. Perhaps the individual nutrients can be leached, distilled, or otherwise chemically separated from compost and biological waste products to enable their reuse in finely-mixed solutions? I don't know. Maybe someone with more knowledge can answer.
WalterBright 4y ago
> The phosphate and potassium parts of this equation are today mined from finite mineral deposits. They don't disappear from the planet when consumed.
- farmaway 4y ago
  Yes, but if they're all dumped in the ocean, burned off as fuel, or buried in landfill then they aren't very useful to humans.
  - WalterBright 4y ago
    People are going to get around to mining landfills. They're surely rich in all sorts of minerals people want.
bjelkeman-again 4y ago
Hydroponic systems are dependent on industrial fertiliser. But you can lower the requirements by at least an order of magnitude by creating circular systems, incorporate food waste into the circularity, and more and create highly effective local and regional nutrient loops. This doesn’t need to stop at the hydroponics system. There are plenty of opportunities to create better nutrient loops in our food production system. We have been working on this for nearly five years. We currently participate in a project which has two dozen companies participating in closing this nutrient loops and create better and more efficient food production.
- farmaway 4y ago
  Thanks for sharing! Checking out the links from your profile, cool stuff. Relevant to where I live, far inland from fresh seafood and in a similar climate zone. With YouTube's auto-translation I can even understand much of what is said in Swedish in the Johannas farm videos. Impressive operation. One question about this video— at 1:46 the speaker says, "fish provide all the nutrients [for] our vegetables, which means we don't have to add anything artificial." Is this accurate? My impression was that aquaponics mitigates, but does not completely eliminate, the need for industrial fertilizers/nutrient solution additives: https://www.youtube.com/watch?v=oGmJETrqzN4&t=1m46s https://www.youtube.com/watch?v=oGmJETrqzN4&t=1m46s Another question— with aquaponics, how do you incorporate food waste into the circularity? Do you feed it to the fish, extract nutrients via an external physical/chemical process, or just dump it in the water and let it decompose? I've heard the latter approach described as "fermented plant juice", and its apparent simplicity is certainly appealing: https://www.ctahr.hawaii.edu/oc/freepubs/pdf/sa-7.pdf https://www.ctahr.hawaii.edu/oc/freepubs/pdf/sa-7.pdf
  - bjelkeman-again 4y ago
    With a nutrient recovery system, bioreactors, for the fish sludge, we think that we can get close to not having any supplemental nutrients for the plants. It depends on the content of the fish feed, the groundwater used etc. Exactly how close to zero time will tell, we are seeing great potential. The key is that the nutrients need to exist in the system in the first place and when you harvest something, you take things out. How do you put what is needed back? We see that a very large portion can be done with circular biological systems. We have been working to incorporate food waste via insects. We take allowed food waste and feed insect larvae. There are several teams in Sweden working on this together, with some government support. I haven't seen the "fermented plant juice" before, but the principle is the same, let bacteria work on it.

moloch-hai 4y ago

Fortunately, there will not be Moon or Mars colonists, or colonies. Electric power to run the LEDs, if obtained from renewables, is protected from cost shocks, but such power might be more profitably sold at such times than used to drive LEDs and sell the produce.

Grimburger 4y ago
> there will not be Moon or Mars colonists, or colonies Bold statement, I'd be impressed if it holds up by mid-century.
- imtringued 4y ago
  I hope you mean in 2072 and not in 2050 because Elon Musk promised to be on Mars by 2018.
- moloch-hai 4y ago
  Try colonizing Antarctica first, on the dirt underneath the ice. If that turns out fantastically popular, do the sea floor. If that succeeds beyond reasonable expectation, you can try out life in an orbiting donut. If that takes off, a Mars colony might have a chance. SpaceX cans are woefully inadequate even to maintain a Mars outpost.
  - Grimburger 4y ago
    Ignoring the fact that multiple colonies already exist on Antarctica and living there is legally restricted to anyone without an army behind them, or that many people live under the ocean for large periods of time?
    - moloch-hai 4y ago
      There are exactly zero colonies on Antarctica. Literally all sites are 100% dependent on regular deliveries of all supplies, excepting air and maybe water, from overseas, with no plan for that ever to change, and no permanent residents. The usual term is "outpost", or for a larger operation, "base". There are no undersea outposts, even. Construction crews sometimes encamp for a few weeks for big hazard pay. There are two (count 'em!) low-orbital outposts that get literally all supplies except sunshine from the ground.
      - Grimburger 4y ago
        The ISS is completely self-sufficient for water and air. No country on Earth is fully self-sufficient in what it uses and is dependent on supplies shipped to it from elsewhere. The word colony in the sense of space exploration and other extreme habitats means permanent occupation and exploitation of the resources there.
farmaway 4y ago
>Fortunately, there will not be Moon or Mars colonists, or colonies. Even if this pessimistic prediction comes true, the same nutrient-recycling solution could support human life in resource-poor regions on Earth, such as Antarctica or Detroit!
linuxftw 4y ago
People actually think we might colonize these places. Like, how are we going to send a bulldozer to the moon? How are we going to fuel it?
- moloch-hai 4y ago
  They were told "we" would colonize, and believe it without thinking. The bigger question is how the liar benefits from the lie. Pumping stock value is the usual guess: (Tesla stock is only now starting to correct, and that largely because of the Twitter debacle.) The fusion-energy startup business runs this way.
- LargoLasskhyfv 4y ago
  With big fucking rockets!

neuronexmachina 4y ago

> The phosphate and potassium parts of this equation are today mined from finite mineral deposits. Sooner or later these mines will close, and we'll have to close to the loop on phosphate and potassium (and molybdenum, calcium, etc.) production and consumption. This was honestly the first I've heard about concerns regarding phosphate and potassium supplies. After some quick googling, possible projections are 2030 for peak phosphate, 2057 for peak potassium: * https://en.wikipedia.org/wiki/Peak_phosphorus https://en.wikipedia.org/wiki/Peak_phosphorus (TIL a large majority of the world's phosphorus reserves are in Morocco) * Peak Potash study: https://www.sciencedirect.com/science/article/abs/pii/S0301420720308667 https://www.sciencedirect.com/science/article/abs/pii/S03014...

farmaway 4y ago
Didn't know peak phosphate was nearly upon us! On the bright side, technologies to recover phosphate via industrial-scale composting are already mature. My home state of Wisconsin leads the way on this, at least in the United States: https://en.wikipedia.org/wiki/Milorganite https://en.wikipedia.org/wiki/Milorganite >Milorganite is a brand of biosolids fertilizer produced by treating sewage sludge by the Milwaukee Metropolitan Sewerage District. The term is a portmanteau of the term Milwaukee Organic Nitrogen. The sewer system of the District collects municipal wastewater from the Milwaukee metropolitan area. After settling, wastewater is treated with microbes to break down organic matter at the Jones Island sewage treatment plant (also called "Water Reclamation Facility") in Milwaukee, Wisconsin. >The byproduct sewage sludge is produced. This is heat-dried with hot air in the range of 900–1,200 °F (482–649 °C), which heats the sewage sludge to at least 176 °F (80 °C) to kill pathogens. The material is then pelletized and marketed throughout the United States under the name Milorganite. The result is recycling of the nitrogen and phosphorus from the waste-stream as fertilizer. >The Milwaukee Metropolitan Sewerage District's Jones Island Plant had the largest wastewater treatment capacity of any in the world when constructed in 1925. It was the first plant in the United States to succeed in using the activated sludge treatment process to produce fertilizer. Potassium is excreted by humans mainly in urine, which is easy to recover. But NPK fertilizer is just one piece of the puzzle. AFAIK, plants require 17 essential micro- and macro-nutrients to grow [0]. I'm just a lay gardener, not a chemist nor research scientist, so I'm not sure how to approach recovering calcium, magnesium, sulfur, or metals like zinc and molybdenum for nutrient solution manufacture. That's the nice thing about composting for soil-based gardening; so long as the right microbes are there to make it bioavailable, all the elements you need are in the used-up biomatter. If it was eaten and not exhaled, sweated out, nor incorporated into the body, it'll be there in the waste stream. [0] https://www.researchgate.net/figure/There-are-17-essential-plant-nutrients-required-for-plant-growth_fig25_272818140 https://www.researchgate.net/figure/There-are-17-essential-p...

wskinner 4y ago

Do conventional farming methods also rely on NPK fertilizers? How do the fertilizer requirements of hydroponics differ from the fertilizer requirements of conventional?

farmaway 4y ago
Yes, they do. Modern industrial farming relies on the exact same fossil fertilizer inputs. When it comes to recycling phosphate etc., the rival to hydroponics and conventional farming is regenerative soil-based agriculture. The latter relies on composting and manuring to turn organic waste back into nutrient-rich soil. Among other functions, microbes in the soil and compost heaps break waste products like urea down into bioavailable forms like ammonium. Hydroponics generally doesn't involve composting and is by definition soil-free, so the plant's rhizosphere is more or less sterile: https://en.wikipedia.org/wiki/Rhizosphere https://en.wikipedia.org/wiki/Rhizosphere To farm plants without soil, they must be supplied with a water-based nutrient solution. The solution contains a precise mixture of all chemical substances a particular plant needs to grow. Yield efficiencies can be realized by carefully tailoring this mixture to each plant. The problem is where to source the ingredients once extracting them from mineral deposits turns uneconomical. Compost- and manure-amended soil theoretically has everything plants need, but that's not very useful for soil-free farming. The precise ratio of nutrients in a given patch of soil is also outside of the farmer's control. Perhaps the individual nutrients can be leached, distilled, or otherwise chemically separated from compost and biological waste products to enable their reuse in finely-mixed solutions? I don't know. Maybe someone with more knowledge can answer.

WalterBright 4y ago

> The phosphate and potassium parts of this equation are today mined from finite mineral deposits. They don't disappear from the planet when consumed.

farmaway 4y ago
Yes, but if they're all dumped in the ocean, burned off as fuel, or buried in landfill then they aren't very useful to humans.
- WalterBright 4y ago
  People are going to get around to mining landfills. They're surely rich in all sorts of minerals people want.

bjelkeman-again 4y ago

Hydroponic systems are dependent on industrial fertiliser. But you can lower the requirements by at least an order of magnitude by creating circular systems, incorporate food waste into the circularity, and more and create highly effective local and regional nutrient loops. This doesn’t need to stop at the hydroponics system. There are plenty of opportunities to create better nutrient loops in our food production system. We have been working on this for nearly five years. We currently participate in a project which has two dozen companies participating in closing this nutrient loops and create better and more efficient food production.

farmaway 4y ago
Thanks for sharing! Checking out the links from your profile, cool stuff. Relevant to where I live, far inland from fresh seafood and in a similar climate zone. With YouTube's auto-translation I can even understand much of what is said in Swedish in the Johannas farm videos. Impressive operation. One question about this video— at 1:46 the speaker says, "fish provide all the nutrients [for] our vegetables, which means we don't have to add anything artificial." Is this accurate? My impression was that aquaponics mitigates, but does not completely eliminate, the need for industrial fertilizers/nutrient solution additives: https://www.youtube.com/watch?v=oGmJETrqzN4&t=1m46s https://www.youtube.com/watch?v=oGmJETrqzN4&t=1m46s Another question— with aquaponics, how do you incorporate food waste into the circularity? Do you feed it to the fish, extract nutrients via an external physical/chemical process, or just dump it in the water and let it decompose? I've heard the latter approach described as "fermented plant juice", and its apparent simplicity is certainly appealing: https://www.ctahr.hawaii.edu/oc/freepubs/pdf/sa-7.pdf https://www.ctahr.hawaii.edu/oc/freepubs/pdf/sa-7.pdf
- bjelkeman-again 4y ago
  With a nutrient recovery system, bioreactors, for the fish sludge, we think that we can get close to not having any supplemental nutrients for the plants. It depends on the content of the fish feed, the groundwater used etc. Exactly how close to zero time will tell, we are seeing great potential. The key is that the nutrients need to exist in the system in the first place and when you harvest something, you take things out. How do you put what is needed back? We see that a very large portion can be done with circular biological systems. We have been working to incorporate food waste via insects. We take allowed food waste and feed insect larvae. There are several teams in Sweden working on this together, with some government support. I haven't seen the "fermented plant juice" before, but the principle is the same, let bacteria work on it.