Where would you imagine one of the most advanced sustainable agricultural practices could be found? Probably in some large urban centre with a university and access to the latest technology, right? Certainly not in a tiny rural village struggling to grow coffee on the volcanic slopes near Retalheuleu.
But advanced vermicomposting, or worm composting, is the foundation of organic coffee production at Loma Linda. Coffee bean wastes are fed to composting worms in three long cement bins. The resulting "castings" or worm compost makes a very rich and sweet smelling organic fertilizer that increases coffee production on the nutrient-poor mountain soils.
The village sits in a short stretch of almost-flat land surrounded by steep volcanic slopes. Here a thin layer of cultivable soil averaging about 30cm deep covers a thick layer of the white volcanic gravelly sand called "poma." So the drainage is excellent, but nutrients are easily washed away in the heavy seasonal rains. The finished castings, in a form resembling the finest topsoil, are applied around the roots of each young coffee plant. Worm compost not only adds nutrients like nitrogen, potassium and calcium, but adds body to the light sandy soils. The results are amazing in terms of higher production.
How did vermicomposting come to this remote finca? It came two and a half years ago when the Asociacion Nacional de Café de Guatemala decided to undertake an experiment in Loma Linda. If the experiment was a success, the simple technology of "lombricultura" could provide a much needed organic soil amendment for organic growers there and in other areas.
With support from the Association, organic coffee growers at Loma Linda built a permanent worm composting facility containing three long bins. Two bins constructed of cement block measuring 6metres by 1m by 60cm high and a smaller one 4metres by 1m by 45cm high, provide a total capacity of about 9 cubic metres of worm habitat.
Setbacks have occurred, but have been overcome. High winds in early 2008 blew part of the roof off, allowing sun to heat the bins to 35 degrees Celsius. 45% of the worms died. Another time, some growers fed the worms untreated coffee wastes, which also heated the bins to unbearable temperatures and created gases toxic to the worms. A third problem occurred when rain penetrated the bins, allowing the moisture level to rise beyond the worms' comfort level. Fortunately, these worms breed quickly, and their numbers were soon back to normal.
The composting worms, which resemble small earthworms, are called "coquetas rojas" in Spanish, "red wigglers" in English, or Eisenia foetida in scientific terms. Unlike ordinary earthworms, these are not native to the region, but to Europe. They have been central to composting facilities around the world where they feed voraciously on food waste, and seem to have a particular taste for coffee.
The technology is simple. Coffee pulp is composted for 30 days to get rid of the gases formed. Then approximately six successive layers of pulp about 10cm thick are fed to the worms, waiting ten to fifteen days until each layer is eaten before the next is applied. When the worms are hungry again, they are fed a final time to bring them to the surface. Approximately 80 percent can then be captured and moved to another bin to begin the process again. The castings are removed and stored in sacks.
At present, 43,000 pounds of worm compost are produced annually, enough to supply the needs of the 87 organic growers. But there are plans to increase the size of the facility and produce enough to sell in the future.
Visitors are always welcome at Loma Linda. Tours and accommodation are available in the village of Loma Linda for those with an interest in green technology. While the internet connection lies in the future, you can call Pascual or Rosa in Guatemala at (502) 4996-2110 (in Spanish)or email firstname.lastname@example.org to arrange for a tour, or to receive more information. If you prefer to communicate in English, you can email the writer and ecotourism volunteer Luisa Ditmars at email@example.com