In 2016, I came to Costa Rica in search of a land destroyed by the methods of human activity. The goal was to restore it and turn it into as many habitats for animals as possible while producing enough food for ourselves to become largely self-sufficient. I found this land in the South-West of the country, an unproductive swamp, toxic from decades of industrial rice cultivation, and when rice would not grow anymore, it was compacted by cattle herds. Local experts were convinced that the restoration of the soil would take a minimum of seven years if not more. Among other challenges, phosphorus levels were concerningly low and erosion was rampant. However, for me a perfect starting point.
We dedicated the first year exclusively to observation and analysis. We observed the sun, the wind, rainfall, micro climates throughout the year, we analysed the soil and water on many different spots, and drew maps with geodesic lines. In the dry season, when the groundwater was low, we walked the swamp and put bamboo sticks wherever we would sink in half a meter or more, to let nature guide us where to dig the wildlife ponds.
We then went on to develop a comprehensive plan, keeping in mind that nature’s strategy is working in cycles and consists of a network of many interconnected elements simultaneously. In permaculture we have a rule of thumb that every element must have at least two functions and every function must have at least one backup, a good start in creating a system whose interrelated elements ultimately become a system which, as a whole, is more than it’s parts.
We started with digging a series of wildlife ponds. The excavated earth we piled up inbetween those ponds resulting in areas that became just high and dry enough for a variety of swamp-trees to flourish, contributing to the reforestation of the biological corridor AMISTOSA. In addition, these ponds now provide habitats for a large variety of animals that had not been able to live here before, such as the boat-billed heron, green ibis and many other birds, turtles, a variety of fish and many others.
The next step was the restoration of the soil for which we applied several interconnected strategies: microorganisms, the Mexican sunflower (Tithonia diversifolia), nitrogen-fixing ‘pioneers’ and weeds.
The microorganisms are the ‘cooks’ for the plants. They transform organic material into plant-available foods. Thus, the more microorganisms a soil contains, the richer it is. First, we breed them through hot compost, which is a method where the heat it produces kills most pathogens and all weed seeds. We then multiply them with compost tea and finally protect them with biochar.
Apart from microorganisms, we planted thousands of Mexican sunflowers, a fast-growing bush that not only fixes nitrogen from the air but also draws phosphorus from rocks in the depth of the soil. Regularly pruned and left on the soil as mulch, it protects the soil and, disintegrating slowly, it replenishes the soil with much needed nutrients and minerals. In addition, we intersperse the reforestation with a large variety and number of short-lived nitrogen-fixing ‘pioneers’, that prepare the soil for the slower growing and more delicate trees.
And finally, we do not uproot so called ‘weeds’. Weeds grow where other plants can’t and draw exactly those nutrients into their stems and leaves that the other plants can’t access. By regularly ‘chopping and dropping’ them they restore the soil and eventually prepare it for any future plant we want to grow. Once the canopy closes the ‘weeds’ have done their job and are shaded out.
The combination of all these strategies led to a failure rate (i.e., the fraction of young trees which do not make it until they can be left alone) of less than 3% on our land, whereas a failure rate of 10% to 15% are not rare in this area. After less than 4 years, soil samples were deemed by the laboratory as the ‘healthiest soil in the whole area’. The University of Costa Rica installed camera traps to monitor wildlife and at their last check in June 2021, they detected, beside many other animals, an ozelot, a puma and a jaguarundi – clear signs that our restoration efforts are working!