Compost Demo at Paititi
posted by Faanito on October 28th, 2012
Contrary to what may would assume, the soil quality in the tropics is very low and at the Paititi Institute our ground is pure clay. Soil building has been a major focus since we established the center and in the last 6 months we have really been dialing in our process. The technique we are using is primarily based on the BioVital compost technique taught to us by the brilliant Paul Taylor from TrustNature as part of an one-week Soil Biology class we attended at Zaytuna Farm, the home of PRI in Australia. We have however slightly altered the technique, tailoring it to suite our specific environment and available resources.
The compost we demonstrated is what is known as an active heap, meaning it is periodically flipped to re-oxygenate it and consequently invigorate microbial activity. As opposed to the popular 18-day Berkley heap, which focuses primarily on creating a product high in available nutrients, our version of the BioVital heap takes about 40 days to complete and produces an output high in biological life.
Nearly all compost-making techniques are based on the premises of achieving a balanced C:N ratio (for more info see http://www.composting101.com/c-n-ratio.html). This technique we taught approximates this ratio by categorizing input materials into three groups: ‘Brown’ (high carbon materials such as dry leaves), ‘Green’ (balanced C:N materials such as freshly cut grass) and ‘Nitrogen’ (high nitrogen materials such as manure). These materials are then stacked in a volumetric ratio of 4(Brown):3(Green):3(Nitrogen), with at least 3 iterations B:G:N and always starting and ending with brown materials.
Our resident master Russian craftsman, Sergey Kuts, recently completed 4 new compost pens (in addition to the two existing pens) as part of the new Soil Building HQ at Paititi Institute. The bins are 3m x 1.5m x 1.2m each in dimension, giving a total volume of 5.4M^3 and a final product of ca. 3M^3. This means we can potentially produce about 18 tons of compost every 40 days!
Brown materials were sourced on-site as we utilized vegetation that was recently cut in our food forest. We also used some rice hulls, to increase silica content, and some sawdust we picked up at a local sawmill. Due to it’s relatively low volume:surface area ratio the sawdust breaks down quickly, and in my experience creates a beautiful spongy soil in very little time. For green materials we used some freshly-cut vegetation and ferns. For high-nitrogen materials we mainly used cow manure but also included some chicken manure (both gathered from neighboring farms) and our kitchen scraps.
After each B:G:N iteration is completed we added two amendments: forest spirit and crushed char (known locally as carbon). Forest spirit is simply any topsoil collected from a healthy functioning ecosystem – in this case our pristine jungle, a couple of meters from the heap. It serves to add a complete representative of the soil food web – thus as we inoculate our heap with it we drastically increase the probability that all the healthy soil biota we require is present once the final product is ready. The powdered char on the other hand is added not only to lock up any toxins and to serve as a housing complex for bacteria, but also to increase the recalcitrance of our compost and ensure a long-term release of nutrients into the rhizosphere. This is especially important in our tropical soils as the rate at which biomass is utilized by the soil life exceeds the rate of biomass deposition and thus effectively inhibits topsoil accumulation. This technique of adding carbon to the soil forms the basis for the legendary fertile soils known as Terra Pretta that were consciously created by the pre-Columbian Amazonian Indians (for more info on this and Biochar in general I highly recommend ‘The Biochar Solution’ by Albert Bates).
With so many eager Gaian-warrior hands abound our brand new jumbo compost pen was filled-up in no time – may it provide food and habitat for countless beings and ultimately produce soul-nourishment that shall fill our bellies and allow us to make some more compost! We look forward to seeing our newborn develop in the next couple of weeks, we’ll keep you guys updated with more blog entries and photos, until then if anyone has more inquires into the details of our creation please don’t hesitate – we LOVE sharing our LOVE!