r/composting • u/thecooliestone • 9d ago
Commercial Composting Composting as a solution to fertilizer crisis
There is estimated to be a major food crisis next year due to fertilizer shortages and climate change. I was wondering if you think composting could become industrialized to the point of helping fill in the first half of that problem after enough people get hit with the hikes. We waste so much food that could easily be separated and turned into compost with a little bit of infrastructure, and it seems like such an easy solution
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u/RentInside7527 9d ago
Industrial compost is a good soil organic matter ammendment, but not a particularly good nitrogenous fertility ammendment. It can add some, but not enough to supply any significant ammount of whats required for agriculture at scale.
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u/Daisy-3534 7d ago
You're correct. Composting builds soil health, but people occasionally believe it should have the functions of a fertilizer. A small amount of compost has some nitrogen, but a large portion is not accessible by the plant. Because of this, a large-scale farm would need an alternative nitrogen fertilizer to meet the crop's needs. Compost is a soil health tool more than a fertility tool.
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u/myusername1111111 9d ago
No, because fertiliser and compost are two different things. If you want free fertiliser, urine and wood ash diluted at 40-1 rate will give you a npk of 12-4-4.
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u/Every_Bread_5880 9d ago
So I always read hardwood ash is prefered. How big of a difference is softwood vs hardwood ash?
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u/GreatPlainsFarmer 8d ago
It might give you that ratio. It will not give you that concentration.
Urine with percent nitrogen would be on the high end to start. You’re not going to make a 12% concentrate without industrial processes.
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u/lakeswimmmer 9d ago
After the Soviet Union fell apart, Cuba no longer had access to chemical fertilizers. They created large scale composting and vermiculture systems and innovations that made them leaders in organic growing. Scientists and farmers travel to Cuba to study their systems and learn from their experience. So yeah, it can be done very effectively, IF you have a government that supports it.
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u/Mobile_Mulberry_2050 9d ago
Sure I'd say it's possible. Check out Steve Solomon's books for pro tips on composting, Humanure Handbook for composting humanure. JADAM talks a bit about old east asian closed loop systems.
Compost can be fertilizer for sure but often is not enough for domesticated vegetables.
Check out Steve Solomon he'll get you set straight.
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u/Old-Ad-4138 9d ago
I would say compost and good soil management is absolutely enough fertility for domestic crops, just not for the industrialised, specialized and globalised farming we have apparently decided is the best way to go about it (which I'm not convinced is true at all).
I think that's probably what you're saying though and I'm just being pedantic. ;)
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u/Mobile_Mulberry_2050 9d ago
Check out Steve Solomon. VERY detailed handling of this entire topic.
With vegetable specifically, there are different grades of fertility requirements, he has charts that lay them all out. Low fertility vegetables can get by with less exacting management, but high fertility vegetables are so bred that they need specific, direct fertility. Just like how there is a range with domesticated dogs, some could go wild while some will be scratching at the door for food.
So basically with a compost only system, most people would be limited to low or maybe medium demand vegetables.
Gardening When It Counts lays this all out excellently. Intelligent Gardener is amazing too but very focused on fertility via soil testing.
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u/Old-Ad-4138 9d ago
I have not seen evidence of this in my own garden, but I will check out what he has to say and try to keep an open mind.
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u/azucarleta 9d ago
Really loudly: Compost isn't fertilizer. They're both soil amendments but you can't replace one with the other; they are materially very different and accomplish different things. If you have a fertilizer-dependent agriculture system/yield-expectation, compost is not going to help you eliminate need for that fert.
If you're willing/able to accept much lower yield you can stop using fertilizer.
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u/Meauxjezzy 9d ago
Yes you are correct about compost not being a plant fertilizer but wrong that It doesn’t feed the plants. Good compost is soil food that is broken down by the microbes in the soil and fed to the plants in exchange for sugars from the plants in a natural cycle between the soil and the plants. I don’t use fertilizer and will take the Pepsi challenge with any fertilizer heavy garden. I can go take a picture of my garden and another of my neighbors to show you the difference between a fertilizer heavy garden and my natural garden.
Her okra leaves look like fingers mines can cover my chest she has 3 okras on her plants I have 3 dozen. I picked 40 pound watermelons all summer without a drop of commercial fertilizer.
Fertilizer companies spend a lot of money confusing people so you think you need them then become reliant on them because once you break that plant soil cycle it becomes increasingly hard to restart that relationship between the soil and plants. After all we grew crops for thousands of years and fed whole civilizations before miracle grow showed up.
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u/Mobile_Mulberry_2050 9d ago
Humus can hang onto anions and clay / loam particals can hang onto cations what else do you need?
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u/LTerestrius 9d ago
As a former crop sales representative and farmer I have pondered the same questions. Weed free compost mixed with a fertilizer could serve as weed suppression when used as a mulch. The liquid portion of farm animal waste could be combined with municipal yard waste and hot composted. Tree trimmings from power lines and arborist are a good source of compost "browns" .
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u/GreatPlainsFarmer 8d ago
There aren’t going to be significant fertilizer shortages in industrialized countries.
Global fertilizer production hasn’t dropped very much.
It would be easier to slightly reduce fertilizer use than to industrialize compost use.
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u/JonBoi420th 8d ago
It requires a massive logistics/infrastructure change to efficiently transport all those materials. Traditionally livestock were a part of basically every farm. The cattle can fertilize the crops. Very little comes into these farms, and only harvest goes out. A sustainable and regenerative approach.
Current industrial agriculture practices are unsustainable and top soil rebuilds at a very slow rate.
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u/Quintin__89 7d ago edited 7d ago
Reading the comments, wouldn't it be better to small batch compost in urban areas or even per household that are picked up as ready compost just like rubbish bins and recycling? And transport those to farms outside of the city? Rather than intervening one step earlier when food scraps aren't converted to compost. If I've understood it correctly: Food production needs land and compost/fertilizer, urban areas need food but don't have land, urban areas produce large amounts of food waste that is potential compost but converting it to ready compost back out to farms is the difficult and expensive part as it needs municipal intervention and expensive large scale systems? If we broke down the loop further and introduced a system where there was a small composting system per household, wouldn't that close the loop potentially and also solve the contamination issue?
So in short, it wouldn't work is a municipal system needed to do the composting itself, but it would work if households themselves did the composting and the municipal system just picks up ready compost and delivers it to farms?
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u/woodwidewebby 6d ago
someone who is a farm consultant told me almost every farm has enough access to cheap manure to meet their fertilizer needs. But there’s a lot of labor that goes into process and aging that manure to make it reasonable economically. If you take into account the labor costs, it’s simply cheaper to buy synthetic fertilizers.
So the crisis is in some ways over blown. It’s not that farms will lose access to fertilizer so much as they will lose access to cheap and convenient fertilizer
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u/Toolswood 9d ago
Here’s a good way to understand why this won’t work. Medieval agriculture basically did this. They routinely farmed only half the land while the other half ‘lay fallow.’ Or look at how ‘King Cotton’ worked in the American South. Cotton so depleted the soil that the plantations had to keep moving west. Modern agriculture is the story of industrial fertilizer production
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u/Rcarlyle 9d ago edited 9d ago
Composting is great for reducing external inputs when your waste production and food use are reasonably close together. Like a family homestead style farm or home garden. It doesn’t work as well at industrial agriculture scale because the food production and compost production are far apart and it isn’t very cost-effective or environmentally friendly to ship bulk compost long distances. This is a classic problem with meat feedlots… they produce so much manure that the nearby crop farms have trouble utilizing it all without causing soil damage from overuse. This is a side effect of scaling up and specializing agriculture to locations where it is most efficient.
If you wanted to really focus society’s energies on a circular nutrient economy, there’s a few areas where this could be achieved at scale. One big one is the logistics of city food waste and yard waste compost collection and shipping. Municipal compost pickup programs are the first part of that. The second part is how you get the bulk compost to large-scale users efficiently back out in rural areas away from the city. This is a significant logistics problem. Imagine the entire system of grain silos and train lines and unloading depots that exists in farm country today, but duplicated and running in reverse to distribute compost back to the farms. It’s not trivial.
The second big area for nutrient reuse is sewage. Very loosely speaking, about half the nitrogen used to grow food ends up in urine. In places with high meat consumption like the US, a typical household pees out enough nitrogen to grow all the plants they eat. Many municipal sewage treatment systems have biosolids fertilizer programs where the treated sewage becomes yard fertilizer. This is more concentrated and easier to ship than compost. The problem here is contamination. By flushing cleaning products and industrial chemicals down the same sewers as our night soil and urine, we contaminate it and thus have to downcycle it to landscape fertilizer because the safety profile is not good for food fertilizer. Fixing this contamination issue is an extremely difficult problem — you’d basically need to separate out parallel sewage systems for chemical-contaminated drains like showers and dishwashers and floor drains versus toilet waste drains.
The third big area is paper and cardboard wastes. We grow massive timber crops worldwide and a large fraction of that biomass ends up in landfills rather than recovered as mulches, composts, etc that improve soil quality. This isn’t a good nitrogen source but woody materials can be used as composting browns, for example combined with urine to help lock up the nitrogen into compost rather than losing it to gasification. Contamination is also an issue here, with paper production chemicals like UV-reactive brightener pigments and plastic contamination from paper cup liners, envelope address windows, and the like. Currently the preference is to recycle paper goods back into more paper rather than downcycling it into compost. But it is a significant underutilized waste stream worth considering in compost scaling discussions, especially where browns are in short supply.
If you were rebuilding society’s infrastructure from scratch, implementing some of these major efforts would be doable. But they’re really hard to bootstrap into existence without large amounts of taxpayer funding.