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My Composting Experiment

“We stand, in most places on earth, only six inches from desolation, for that is the thickness of the topsoil layer upon which the entire life of the planet depends.” R. Neil Sampson in Farmland or Wasteland: A Time to Choose

One of my interests, dating back 25 years to when I was a member of my local FFA land judging team, is soil conservation. I have long been interested in things like terra preta and composting because of their ability to build topsoil. But I never thought much about how difficult it can be to build up topsoil until I read Kim Stanley Robinson’s Mars Trilogy – Red Mars, Green Mars and Blue Mars(great books, by the way). The books trace a future hypothetical terraforming of Mars, and one of the major difficulties the characters face is producing topsoil on the planet. It was then that my interest in the mechanisms for topsoil erosion and topsoil production greatly increased.

While I would eventually like to get some experience with producing terra preta, earlier this year I got a flyer from Waste Aware Scotland for discounted composters. So, I bought one, and started to experiment. I wish I had done so years ago, because it has really been a fascinating exercise.

My 330 Liter ecoMax

I got the larger 330 L (87 gallon) model shown above and started dumping all things cellulosic into it. There is quite a little tropical ecosystem inside the composter. Even when it is cold outside, the waste is always steaming. And not only has it attracted numerous earthworms, but there are beetles, slugs, and lots of insects I haven’t been able to identify. Besides being an interesting science experiment, there are major environmental benefits from composting. According to the most recent newsletter from Waste Aware Scotland:

• It reduces waste sent to landfill

Scotland produces 900,000 tonnes of organic waste a year. That’s enough to fill Hampden Stadium more than 18 times. We could divert a large amount of organic waste from landfill by using it for home composting.

• Reduce global warming

Organic waste sent to landfill cannot decompose properly because it doesn’t have access to air. As a result, it produces methane, which is a powerful greenhouse gas that contributes to global warming.

• Your garden benefits

Compost improves soil, so plants in your garden become healthier and more pest and disease resistant. They will produce better fruit and vegetables and more beautiful blooms.

As I explained to my daughter, who recently told me she wants to become more environmentally responsible, there are two ways in which composting combats global warming. The first is the reduction of anaerobic digestion, which results in methane production as explained above. Because methane is such a potent greenhouse gas, this is not something you want occurring in an open landfill. But the second benefit is that home composting reduces the mass of material that would be transported (via fossil fuels) to the landfill. So home composting is much more environmentally responsible than throwing your waste in the trash.

So, what can you compost? Again, referring back to the newsletter:

Kitchen waste:

✔ Fruit scraps and vegetable peelings
✔ Tea leaves/bags and coffee grounds
✔ Egg shells
✔ Paper items which can include scrunched up cardboard, egg boxes, toilet roll tubes, vacuum cleaner bags, cereal boxes and paper towels

Garden waste:

✔ Cut flowers
✔ Garden and house plants
✔ Grass cuttings
✔ Young annual weeds
✔ Shredded twigs
✔ Hedge trimmings
✔ Straw and hay
✔ Wood chippings and sawdust
✔ Hamster or other pet bedding

If you start to segregate your garbage, you will find that these items make up a substantial portion of what would normally go to the landfill.

Inside My Composter – Yuck

In the picture above, the composter contains about 30 gallons of composting material. But I have filled it to the top at least 10 times and haven’t taken anything out of it. In other words, that 30 gallons of material was originally around 1,000 gallons. It is amazing how much the volume is reduced as it decomposes. But that also goes to show how much material it takes to produce an inch of topsoil.

So get yourself a composter(or make one) and do a bit more for the environment. You may even find that you enjoy it.

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September 2, 2007 - Posted by | composting, environment, global warming

25 Comments

  1. Yeah, composting is fun. And it’s super easy, if you’re not worried about making “high quality” (i.e. high nitrogen, mostly) compost.Making compost good enough to substantially replace fertilizer in otherwise low-nutrient soil is an art (and not one that I possess) and takes a fair amount of attention. But most soil will benefit from additional organic matter, and that’s easy to produce, as you’ve seen.And, yeah, you will start to wonder if there isn’t some kind of giant pit under your composter: you keep adding stuff, and more stuff, and more stuff, and it just never gets full.And, yes, it’s also a good way to ground (literally and figuratively) your understanding of waste, decay, and soil building processes. I wish that Dyson had tried his hand at it before he penned his “global warming heresy” essay (http://tinyurl.com/yozuja), in which he suggests that concern with carbon is overblown because our fossil fuel combustion “only” represents a 1/100″ layer of carbon over the land area of the planet. Building 1/100″ of soil takes time and work and a hell of alot of organic matter, but I doubt that Dyson has ever left his ivory tower long enough to learn this fact first-hand.

    Comment by GreenEngineer | September 2, 2007

  2. Your blog’s informative is very rich in contents. I like your way of presentation. At times I disagree with your views but thinking about it who presents views that are acceptable to everyone. Keep posting your good blogs.

    Comment by KIm | September 2, 2007

  3. As a bystander, it looks to me like soil scientists are really just beginning to learn how the soil system works (particularly the microbial aspect), what practices damage the system and what practices improve it (which, IMO is why biofuel production could be very dangerous if the wrong practices are used).Some blogs with material on soils: Soil Science Journal Clubhttp://myresearchspace.grs.uwa.edu.au/blogs/andrewrates_blog/Transect Points – Philip Small, Soil Scientist, Spokane, WA (inactive during his work season)http://transectpoints.blogspot.com/Muck And Mysteryhttp://www.garyjones.org/mt/Other materials:The Soil Biology Primer (on-line, USDA NRCS)Goggling “terra preta”: From the Terra Preta Homepage: “Terra Preta (do indio) is a black earth-like anthropogenic soil with enhanced fertility due to high levels of soil organic matter (SOM) and nutrients such as nitrogen, phosphorus, potassium, and calcium embedded in a landscape of infertile soils (see soil profiles below). Terra Preta soils occur in small patches averaging 20 ha, but 350 ha sites have also been reported. These partly over 2000 years old man made soils occur in the Brazilian Amazon basin and other regions of South America such as Ecuador and Peru but also in Western Africa (Benin, Liberia) and in the savannas of South Africa. Terra Preta soils are very popularby the local farmers and are used especially to produce cash crops such as papaya and mango, which grow about three times as rapid as on surrounding infertile soils.”Clapperton, M. Jill (Rhizosphere Ecology, Lethbridge Research Centre) – “Worm World”Building Soils for Better Crops, 2nd ed., Fred Magdoff, Harold van Es, 2000 (online pdf)Glomalin: Hiding Place for a Third of the World’s Stored Soil Carbon (2002)Glomalin: Materials and methods for analysis (S. Wright, K Nichols, 2005)JMG3Y

    Comment by Anonymous | September 2, 2007

  4. In the 70’s there was a great paperback book, in semi-hippie style, called “let it rot.” It was a practical guide to composting and I loved it … but it also held the caution that if you started to show your compost pile to your friends you might be taking things too far ;-).I caught myself showing my compost pile to my high school friends …Anyway, years lahttp://www.bbc.co.uk/radio4/science/costingtheearth_20050414.shtmlter I got a great kick out of < HREF="" REL="nofollow">this BBC production (on-line)<>, and their talk to the man running “the rocket.” Enjoy.Though, I really think landfills are underrated for carbon incarceration. Those “digs” that have found readable 1950’s newspapers aren’t finding bad (methane producing) breakdown. They were finding preservation.So sure, some methane might be produced from a badly designed landfill … but what fraction of carbon is still there in a century in a well designed one?

    Comment by odograph | September 2, 2007

  5. bah, i messed up my link. trying again:< HREF="http://www.bbc.co.uk/radio4/science/costingtheearth_20050414.shtml" REL="nofollow">COSTING THE EARTH: The best meal you’ll never have!<>

    Comment by odograph | September 2, 2007

  6. Oops. Back on the ground, I’ll put the links in HTML:< HREF="http://myresearchspace.grs.uwa.edu.au/blogs/andrewrates_blog/" REL="nofollow">Soil Science Journal Club<>: a resource for people interested in recent advances in Soil Science in all its guises< HREF="http://transectpoints.blogspot.com/" REL="nofollow">Transect Points<> Philip Small, soil scientist< HREF="http://www.garyjones.org/mt/" REL="nofollow">Muck & Mystery<> Gary Jones, CA soil scientist / grazier

    Comment by Anonymous | September 3, 2007

  7. As a long-time composter, organic gardener, and rice-grower (who would have guessed?), I applaud your effort at composting. People interested in composting but who don’t want to buy a composter should note that you don’t need anything to compost except organic material. Just pile your material on the ground, and when it reaches critical mass, it will spontaneously start to decompose. If the weather is hot and dry, dump water on the pile (bacteria need water, just like you and me). The advantage to a composter or other enclosure, of course, is that it holds in heat and allows the bacteria to work in colder weather. It also keeps small animals out of your garbage.

    Comment by Rice Farmer | September 3, 2007

  8. <>“We stand, in most places on earth, only six inches from desolation, for that is the thickness of the topsoil layer upon which the entire life of the planet depends.”<> R. Neil SampsonWhich reminds me that in the original Sauk language, the word “Iowa” means “world’s largest, shallowest strip mine.”<>Odograph said:<><>“In the 70’s there was a great paperback book, in semi-hippie style, called “let it rot.” It was a practical guide to composting and I loved it…”<>Speaking of the 70’s, I still have my original copy of <>The Last Whole Earth Catalog<> — printed in 1971 and for which I paid $5.The book on composting it mentions is <>Composting<> by Harold Gotaas, published in 1956 and available for $5.00 from <>The American Public Health Association<>, 1740 Brodway, NY, NY 10019.(What are the chances there is still an American Public Health Association on Broadway selling books on composting?)

    Comment by Gary Dikkers | September 4, 2007

  9. I have a blog containing good < HREF="http://xieng.notlong.com" REL="nofollow">information on global warming<>. Ozone has doubled since the mid-19th century due to chemical emissions from vehicles, industrial processes and the burning of forests, the British climate researchers wrote. Carbon dioxide has also risen over that period. < HREF="http://xieng.notlong.com" REL="nofollow">History of global warming<> is very deep since 1850.

    Comment by Michelle Hudson | September 4, 2007

  10. From a chemist’s point of view, what exactly are the key ingredients in “top soil”?I’m also a fan of composting but I confess I’ve been leery of trying it for fear of creating something stinky and something that would attract vermin and bugs.A middle ground might be for the refuse collection to dump organic waste into a big composter. In some areas I believe this is already done with yard waste.

    Comment by Doug | September 4, 2007

  11. Healthy top soil is mineral dirt, organic matter in various states and structures, and lots of living and dying organisms. I don’t have the reference offhand, but I’ve read that living bacteria can make up a significant fraction (20+%?) of a healthy soil by mass.The actual chemical and mineral components will depend on local soil, climate, and amendments that have been added. For example, a sandy soil in a place with alot of rain will tend to be low in water soluble nutrients (like Nitrogen) and may have a superabundance of non-soluble nutrients. Apparently this is a problem for gardeners in places like the pacific northwest.As for home composting: If you avoid adding meat or dairy, and you keep the pile well-aerated, you won’t have stinkiness or scavenger problems. Mice will nest in a compost pile, but if you keep it moist and turn it every couple of months, you’ll disrupt their habitat and they shouldn’t be a problem. The key is the right balance of air and water (damp like a wrung sponge) and the right balance of high-nitrogen materials (e.g. food scraps, green grass) and high-carbon materials (e.g. dry grass, straw). If it gets slimy or stinky, that’s a result of anaerobic decomposition, which means you need to aerate the pile and/or add dry brown materials.

    Comment by GreenEngineer | September 4, 2007

  12. <>We stand, in most places on earth, only six inches from desolation, for that is the thickness of the topsoil layer upon which the entire life of the planet depends.<>Allow me to be the contrarian, enabled as I am by < HREF="http://en.wikipedia.org/wiki/Hydroponics" REL="nofollow">Wikipedia<>: <>In natural conditions, soil acts as a mineral nutrient reservoir but <>the soil itself is not essential to plant growth<>. When the mineral nutrients in the soil dissolve in water, plant roots are able to absorb them. When the required mineral nutrients are introduced into a plant’s water supply artificially, <>soil is no longer required for the plant to thrive<>. Almost any terrestrial plant will grow with hydroponics, but some will do better than others. It is also very easy to do; the activity is often undertaken by very young children with such plants as watercress. Hydroponics is also a standard technique in biology research and teaching and a popular hobby.<>So if soil production is holding up the colonization of Mars, there is a simple solution: do it without soil. Much harder work, for sure, but possible.Now let me go the whole hog with this heresy: composting is nice old technology and it may bring you closer to the earth and all that – but in a resource constrained future there is no place for composting. Especially if you are concerned about energy. Composting does not allow for any of the energy in your feedstock to be recovered. In short: we need to do better than that.We should at least be looking to recover <>both<> the energy <>and<> the nutrients from our wastes. Gasification (and even cellulosic ethanol if it works) allows one to recover energy <>and<> nutrients. Can be done. And should.Let me be clear: I am not advocating strip mining of nutients. But composting is just too low efficiency to be much of a solution for the the future.

    Comment by Optimist | September 4, 2007

  13. <>But I have filled it to the top at least 10 times and haven’t taken anything out of it. In other words, that 30 gallons of material was originally around 1,000 gallons. It is amazing how much the volume is reduced as it decomposes.<>A lot of that is just compaction: Uncompacted household waste has a specific gravity of 0.4 to 0.6 (RR can test his and report the results here). Soils vary from 1.1 to 2.1. So a good part of that volume change is compaction.

    Comment by Optimist | September 4, 2007

  14. With regard to hydroponics and raising plants soil-free, researchers recently discovered a symbiotic relationship between soil fungi and plants that enhances plant growth efficiency. However, conventional tillage and fertilization practices often markedly reduce this fungal population.< HREF="http://en.wikipedia.org/wiki/Arbuscular_mycorrhiza" REL="nofollow">Arbuscular mycorrhiza<>< HREF="http://en.wikipedia.org/wiki/Glomalin" REL="nofollow">glomalin<>

    Comment by Anonymous | September 4, 2007

  15. optimist,You’re statement is correct, so far as it goes, but you’re badly underestimating the value of a good level of organic matter and the associated biological (microbial and fungal) soil activity. The science behind it is still just emerging, but as a grower I can tell you that it’s real: plants grow better, take less care, produce more food, and are much healthier if the soil itself is healthy.Composting is only secondarily about nutrient cycling. Mostly its about biomass cycling, and that’s every bit as important as nutrients. (Sir Albert Howard talks about how modern ag is overly fixated on NPK, and he’s right.)As we all know, biomass isn’t very energy dense. Much of it is not even worth the effort/energy to transport it, even assuming an ideal biomass-to-energy scheme. So composting has its place in small-scale operations. And it will have to continue on large scales as well: One of the most worrisome things about BTL and BTE schemes as a class is that they tend to presume that any biomass that humans are not actively using is up for grabs. That’s not the case, though, because the local plant community is using that biomass, and will suffer if it is systematically removed over a long period of time.

    Comment by GreenEngineer | September 5, 2007

  16. “As we all know, biomass isn’t very energy dense. Much of it is not even worth the effort/energy to transport it, even assuming an ideal biomass-to-energy scheme.”Except for firewood,…and a bunch of other stuff:According to the EIA, biomass is the largest renewable energy source.http://www.eia.doe.gov/cneaf/solar.renewables/page/trends/table1.htmlThere must be a lot of money being lost, since it’s not worth it.What <>is<> the “ideal” biomass-to-enrgy scheme?

    Comment by Anonymous | September 5, 2007

  17. My comment was about marginal sources of biomass, e.g. leaf litter, garden waste, etc. The sort of thing that was applicable in the context of the comment to which I was responding (which said that we need to convert all our waste to energy, rather than composting it). <>Obviously<> I wasn’t talking about firewood or other dense sources. Duh.An “ideal” BTL/BTE scheme would be high efficiency, low pollution, fast, and use little water. All the existing schemes that I know of are deficient in one or more of these areas. But even if the conversion process were really good, moving megatons of leaf litter may not be worthwhile. Unless you can also make these plants cheap and effective at small sizes. Then you can build lots of them, or move them to where the resource is.I guess if you add “portable” to the list of ideal BTL/E system characteristics, then the feedstock transportation problems go away. Does it come with a puppy too?

    Comment by GreenEngineer | September 5, 2007

  18. <>Mostly its about biomass cycling, and that’s every bit as important as nutrients.<>I think you lost me there, champ. <>Biomass<> recycling? What on earth?<>The science behind it is still just emerging, but as a grower I can tell you that it’s real: plants grow better, take less care, produce more food, and are much healthier if the soil itself is healthy.<>I don’t dispute that. My question is: Can we afford this luxury?<>But even if the conversion process were really good, moving megatons of leaf litter may not be worthwhile.<>Current practise is to <>move megatons of leaf litter<> (and other garden waste) to landfills. Surely, diverting it to a BTL plant won’t involve much more transportation.My point remains: we need to recover as much of the energy <>and<> nutrients as we can. The ashes of BTL will contain the bulk of the P & K. To capture the N would require some innovation, but not too different from existing technology for scrubbing NOx from off-gas.

    Comment by Optimist | September 5, 2007

  19. I’ve been keeping a worm bin for years, in which I compost all my kitchen waste (only). When properly balanced with dead leaves for bedding, it never goes into anaerobic decomposition and so it never gets stinky. And boy, do those worms chow through the stuff I put in there. A separate cellulosic compost pile, where things can heat up under anaerobic decomposition, can be un-stinky without the kitchen waste in it.

    Comment by Chris Nelder | September 5, 2007

  20. <>Organic waste sent to landfill cannot decompose properly because it doesn’t have access to air. As a result, it produces methane, which is a powerful greenhouse gas that contributes to global warming.<>I found that comment interesting. I know that under certain conditions compost facilities can <>stink<>, which would suggest less than complete aeration. How complete is the aeration in a well designed system, like the one you purchased? I know they often recommend letting the product mature (outside the composter, i.e. anaerobically), how much methane would that produce?

    Comment by Optimist | September 5, 2007

  21. <>I think you lost me there, champ. Biomass recycling? What on earth?<>Cycling, not recycling, but whatever. That’s how soil gets made. I could have said “carbon cycling”, but that’s a broader term that could encompass many other phenomenon as well.Go to a well-established forest, and dig down into the duff. You’ll see biomass in all different stages of decomposition. That process is essential to the health of the trees. Strip that duff away and you will eventually kill the forest.Similar processes exist in other biomes, although they often look different. On a perennial prairie, for example, a lot of the cycling happens as root systems die back when the plants go dormant. In a system like that, you can probably harvest some amount (but certainly not all!) of the above-ground biomass without harming the long-term health of your soil.<>I don’t dispute that. My question is: Can we afford this luxury?<>What you’re asking is, can we afford the luxury of growing food without fossil fuel inputs? 🙂Seriously: You can grow with high chemical input, which is energy intensive. Or you can grow with healthy soil, which is not.In addition to supporting crucial soil microbial activity, organic matter is a key factor in nutrient availability and retention. So if you’re worried about plant nutrient shortages, you <>really<> want a high organic matter soil.<>Current practise is to move megatons of leaf litter (and other garden waste) to landfills. Surely, diverting it to a BTL plant won’t involve much more transportation.<>Yeah, and that’s a stupid practice, too. Bagging and removing fallen leaves and cut grass is a luxury of a cheap fossil fuel society. If we get as tight on energy as you are suggesting (and we may well), then that practice is going to stop. It’s already strongly discouraged in many places. Continuing the practice, but sending the leaves to a BTL plant rather than a landfill, is slightly less wasteful but almost certainly still a net energy loser.

    Comment by GreenEngineer | September 5, 2007

  22. <>A separate cellulosic compost pile, where things can heat up under anaerobic decomposition, can be un-stinky without the kitchen waste in it.<>Most thermophilic bacteria are actually aerobes. A hot pile is nice for speed, and for killing weed seeds (and decomposing herbicides), but it’s not necessary. You can have a slow moldering pile that doesn’t heat up much; as long as it’s kept aerated and not too wet, it won’t smell much.

    Comment by GreenEngineer | September 5, 2007

  23. <>Continuing the practice, but sending the leaves to a BTL plant rather than a landfill, is slightly less wasteful but almost certainly still a net energy loser.<>Nope. In the current practise you simply send everything to waste. BTL affords you to recover both energy and nutrients. <>Slightly less wasteful?<> LOL! It’s like saying recycling is <>slightly less wasteful<> than tossing into the landfill.Net energy loser? How did you compute that? You are recovering all that energy stored in the biomass, which basically acts as a self-replicating solar collector.<>I could have said “carbon cycling”, but that’s a broader term that could encompass many other phenomenon as well.<>I have a different carbon cycle in mind. IMHO we cannot afford to leave the precious carbon to the microbes.<>Seriously: You can grow with high chemical input, which is energy intensive. Or you can grow with healthy soil, which is not.<>It does not have to be <>high chemical input<>, it can be ash from BTL and other waste products. Wastewater plants can recover a lot of nitrogen, unlike the current practise, which is to convert ammonia back to molecular nitrogen using electrical power to do so.There are many possibilities. Composting IMHO is like biodiesel: great for the DIYer, but not a good large scale solution.

    Comment by Optimist | September 6, 2007

  24. Googling “large scale urban composting”:1,000 cubic yard per day < HREF="http://www.californiagreensolutions.com/cgi-bin/gt/tpl.h,content=294" REL="nofollow"> commercial compost facility<>Market Status Report: < HREF="http://www.ciwmb.ca.gov/Markets/StatusRpts/compost.htm" REL="nofollow"> Urban Compost and Mulch <>Markets for Compost – a key factor for success of urban composting schemes in developing countries. < HREF="http://www.eawag.ch/organisation/abteilungen/sandec/publikationen/publications_swm/downloads_swm/city_matters-markets_for_compost.pdf" REL="nofollow"> pdf <>Decentralised composting of urban waste – an overview of community and private initiatives in Indian cities < HREF="http://www.eawag.ch/organisation/abteilungen/sandec/publikationen/publications_swm/downloads_swm/decentralised-Composting-in-India.pdf" REL="nofollow">pdf<>

    Comment by Anonymous | September 6, 2007

  25. <>I found that comment interesting. I know that under certain conditions compost facilities can stink, which would suggest less than complete aeration.<>That depends on what you mean by “stink”. A happy compost pile has a definite smell. It’s earthy, not foul, but it could still be overwhelming on an industrial scale.If the smell is foul, then that is an indication of a problem. It could be a temporary condition (recent rains compacting the pile) or a sign of ongoing bad management.<>How complete is the aeration in a well designed system, like the one you purchased? I know they often recommend letting the product mature (outside the composter, i.e. anaerobically), how much methane would that produce?<>The sort of composter Robert got is really just a bin. There’s no aeration system, except that the sides are perforated.Letting compost mature is a good idea if the compost is “hot” (i.e. very high in available nitrogen, which can burn plants). The only reason to do this outside of the composter, though, is to avoid adding new material to the product while it finishes composting. Anaerobic digestion is definitely NOT the goal there. The last thing you want to do is spread anerobic compost on your plants — it will likely kill them.If you want to maximize energy utility, you could do a two-stage process: anaerobic first, to harvest methane, followed by a aerobic decomposition of the resulting sludge (probably after mixing it with some dry brown matter to add loft and lost carbon). This level of effort would only make sense on the scale of a good-sized farm, though.

    Comment by GreenEngineer | September 6, 2007


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