Pensamientos: Fermenting Cow Poo: Lessons in Homebrew Biol, an Organic Liquid Fertilizer

Reading: A Farewell to Arms by Ernest Hemingway

La Casa de Abonos

Seeing as I have been in Paccha for nearly six months now, I suppose that a few of my faithful readers are scratching their heads and asking, “what would ya say you do here?” A fair question, given that this blog leaves one to assume that I travel, go to rodeos, rant about women’s station in the world, provide a running social commentary on all things unimportant, listen to music, and photograph flowers – none of which resemble a Peace Corps project… sure I have left hints here and there of said project, but it has been pretty on the DL until now.

I will forewarn you, it’s going to get a little dirty…. it struck me yesterday while I was ankle deep in cow poop that the most satisfying jobs I have had in life have always involved me shoveling large amounts of poop. Not only could this be some sick metaphor for my life, but it reminded me of a recent Radiolab episode that described the afterlife as reliving “all your experience but this time with the events reshuffled into a new order… all the moments that share a quality are grouped together… for instance two years of boredom staring out a bus window, sitting in an airport.” In such a world, I wonder what my time count would be for shoveling poop or even just moving poop... but I digress.

My inflated LinkenIn profile states, “currently, I oversee an organic fertilizer project with a small group of sugar cane farmers. The goals of the project include improving individual annual harvests, as well as providing a secondary source of income. The project is heavily focused in agriculture sustainability.” Yes, I would really, really like a job or to go to grad school when I finish Peace Corps and am hawking myself on online résumé sites.

What I really do is act as the nagging presence to a group of nine socios who, along with the previous Peace Corps volunteer in Paccha, Jack, started this organic fertilizer project where they produce a liquid fertilizer and a solid compost. This all goes to say that it is really the brainchild of Jack and I was simply handed a beautifully managed project to see to completion or in Peace Corps/development lingo, sustainability. My actual work is pretty easy, I help shovel some poop, I check to make sure tanks are fermenting correctly, and every so often I bat my pretty, blue, gringa eyes when we need some machines or money from the municipal government.

What can you do with a dump truck of manure?

Really, I could not ask for a more ideal project. Jack fashioned the whole thing after spending his first year working with a struggling association of sugar cane farmers. Aside from the normal anxieties that small farmers face, Jack found that few of the socios used any sort of fertilizer on their crops, in part because the association wanted to maintain their organic certification from Italy, the major consumer of their sugar, but also because they lacked the resources, both monetary and information, to do so. Jack, being the pragmatic guy that he is, realized that Paccha had all the essential resources available to the socios to make some pretty legit compost. They started with a few small batched, were impressed with the results, and thus moved onto bigger things like… fermented cow poop!

Peace Corps had provided all the sustainable agriculture volunteers with a recipe for an organic liquid fertilizer called biol while in training. There are several variations on this recipe, yet it seems to only exist in the agricultural world of Ecuador – the Ministry of Ag is a huge promoter of it, as are many of the organic banana plantations. Yet there is next to no actual research on why this stuff works as great as it does. Being in Ecuador does not really help that matter… we have a pretty crude assay that we run down here. It involves two plants, one receiving the fertilizer and one that does not. You cross your fingers that the plant receiving fares better throughout the growing season. Luckily Nature and science usually rule in our favor.

Mixing the "dry" ingredients for biol

The actual biol recipe looks something like this:

50 lbs of cow manure
3 liters of sugar cane syrup
250 grams of fresh yeast or 1 liter of microorganism solution
1 liter of fresh milk
3 pounds of ash
2.5 pounds of fresh chopped leguminous material (green leaves from nitrogen-fixing plants)
3.5 pounds of rock phosphate
60 liters of water

You also need:

100 liter plastic tank with a top (you must be able to realize a hermetically sealed environment inside the tank)
1 meter of gas hosing
1 water tank adaptor that will allow the hose to connect to a hole in the top of the tank without leaks
1 top-tank fastener
1 empty 2 liter bottle

With my project, the recipe has been tweaked a little to accommodate resources that we have readily available here in Paccha, but the idea is still the same. We also scaled it up quite a bit. As in, we make our biol in batches of 1200L across five 600L tanks. There are a few things that are worth nothing, for those of you who might have the ganas to try this at home. I would high recommend it.

First, the hermetic seal is clutch. Since we are not making this stuff in an actual lab, I cannot provide a really great explanation as to why fermenting this stuff is important. Surely, if I spent the next week pouring over some bioprocesses textbooks, I could do so… but I’m saving that for a master’s thesis. Either way, it needs to be an anaerobic process. Otherwise your biol comes out smelling horrible and does nothing bueno for your plants. Now, I know you are probably thinking, “you are brewing poop beer, how could it not smell awful?” Fair. But I assure you, properly made biol has a sweet, earthy poop smell to it, as opposed to the rancid, sour poop smell of biol gone bad. There is a big difference, I promise you, and you are better off just taking my word on this one.

Hermetically sealed tanks with bubblers

To get a good hermetic seal, we use silicone to seal to top of our tanks. However, since this is a fermentation reaction (like pyruvate to ethanol in plants) carbon dioxide is produced and consequently needs a way to exit the tank. (Unless you are looking to make a glorified liquid poop bomb.) This can be done by adding a hose to the top of the tank, obviously sealed to prevent any seeping of air into the system. The end of the hose not connected to the tank should be submerged in a bottle of water to prevent any air from entering. It also serves as a rudimentary means of determining when the batch is completed. Normally, it takes about two months for the entire fermentation process to go to completion, which can be noted by the lack of CO2 bubbles coming from the hose.

Following that, it is important to keep in mind that this is a live culture, so do not leave out the yeast, milk, and sugar/molasses. There is tons of evidence of the importance of microorganisms in improving soil quality and one of the presumed (remember, there is no laboratory research on all of this) benefits to biol is that it is full of microorganisms. Personally, I have a lot of questions pertaining to the shelf life of said microorganisms, how significant they are, etc. But hey, even when shooting from the hip, it never hurts to aim a little.

As for the actual brewing process, we found that it works best to premix the manure, ash, rock phosphate, and leaves. Once thoroughly mixed, we bag the mixture into permeable grain bags. I like to think of it as a large tea bag, allowing for steeping of the biol ingredients but making the removal processes a lot less painful and dirty. The milk, yeast, and sugar/molasses can be added directly too the tank. There is also the possibility of adding magnesium sulfate if so desired. It is also important to remember to leave a few inches at the top when finally filling the tank with water to allow for expansion.

Bagazo for the compost

The forth thing that I think is imperative to this is feasibility and availability. When Jack initially started this project, he was very and justifiably concerned with costs. He had to make sure that this homebrew fertilizer was a more economical option for the socios than just going out and buying a conventional fertilizer. (It is hard to always argue environmental benefits against the bottom line no matter how much of an idealist you are.) Luckily, in Paccha, that was very reasonably to do. First, when processing sugar cane into sugar, there is a lot of waste that comes in two primary forms. The first being bagazo or the dried husks of the cane after it has been pressed, which we use as the carbon browns in our compost. Ash is the second, and thus every socio has an abundant supply at no cost. The same can be said for the leguminous material, as there are plenty leguminous trees endemic to the area.

Nine square meters of cow poo

With regards to the manure, there just so happens to be a slaughterhouse in Paccha complete with a very large vat where all of the poop and stray innards from the week are disposed. It only involved a little convincing on the part of Jack to have the municipality civil works sector help us help them get rid of all of that every few months. So with nine square meters of fresh manure at our fingertips, it makes it quite simple to produce 2 tones of compost and 1000L of biol every three months.

At this point, you are probably saying, “wow this sounds really amazing but what are you doing with the rest of the time of have in Peace Corps?” Well, in short, I am nagging. Nagging to make sure that the socios are actually using the fertilizer. Primarily, because we made this to benefit their crop yields, but those results will not happen if the biol is not actually applied. Application is also important because it serves as the equivalent to our “lab-tested and proved” results. The project is currently producing more that the socios use on their own farms even under ideal circumstances. Thus the hope is that people will be impressed with the results and want to start buying this stuff. Making a batch of this fertilizer requires very few hours of labor and minimal monetary input. So there is opportunity for a pretty high profit margin, it just involves some clever marketing. Old habits die hard, right? Well, we are looking to prove that wrong.

Tank of finished biol

So far, that has been rather challenging. In a part of the country where people are not use to paying to fertilize their plants, it is hard to convince them at even something that is as cheep as $0.50/L is worth their money. Slowly, though, it is catching on. If nothing else, my school garden has become a loyal customer. By the end of the school year, all of my forth graders will be fully convinced that you cannot grow great tomatoes unless you feed them smelly, liquid poo every week. But more on that later…

For now, happy fermenting, whether it be beer, apple cider, or some fragrant cow poop.