By Taylor Walker
There is a lot of talk these days regarding global climate change, soil loss, and desertification. We as farmers, gardeners, and stewards of the earth can play a major role in slowing and even reversing these catastrophic trends. Thankfully there are many solutions at hand if we use thoughtful techniques and look to the natural environment for ideas and answers.
In nature plants do not grow only in one plane but grow in all dimensions. Most natural terrestrial ecosystems consist of many different species of plants and plant types. Groundcovers, vines, herbs, shrubs, understory trees, canopy trees, and emergent canopy trees are all present in a tropical forest. As anyone who has farmed or gardened in Belize surely has witnessed any cleared land left to its devices quickly begins to reforest itself in a tangle of herbs, vines, and hard tree species. These pioneer species are the first plants to colonize an area after the land is cleared either by farming, overgrazing, or fire. These species are often called weeds. A weed is just a name for a plant in a place that we don’t want it or that we have failed to discover its purpose and function.
Each pioneer species has a specific purpose and function. Many stabilize the open topsoil with dense roots; other species can loosen compacted soils with tough penetrating roots. Some species can accumulate minerals from deeper soil levels and make them accessible to shallow rooted species through their growth and decomposition of leaves and branches. One of the most significant categories of pioneer plants is the nitrogen-fixing plants. These plants have natural symbiotic relationships with certain soil-borne bacteria that can absorb atmospheric nitrogen and convert it to a form of nitrogen useful to all plants. The air that we breathe is approximately 70% nitrogen, but this is of little use to plants that rely on this vital nutrient for growth; it must be sequestered by nitrogen fixing species and converted to the plant soluble form of nitrogen. By planting 30% of your canopy or 70% of ground cover/herbaceous plants in nitrogen fixing species most or all nitrogen requirement will be fulfilled. These levels of nitrogen produced are very real and can amount to over 150 pounds of nitrogen per acre per year. This amount is equivalent to over 5000 pounds of chicken manure added per acre per year.
Farmers can take the path of least resistance and plan their farms to replicate this natural succession of species. I always say that you can plant useful herbaceous “weed like” species or spend much of your labor input controlling or removing unwanted wild weeds. Why not spend your time harvesting instead of weeding? By modeling our gardens or farms after natural young forests we are taking proper advantage of the natural cycles and synergies present in a healthy ecosystem. These synergies include nutrient cycling, soil building, erosion control, groundwater recharge, carbon sequestration, evaporative cooling, mineral accumulation, nitrogen fixation, beneficial microbial activity, predatory (pest consuming) organisms, and other diverse symbiotic relationships. By diversifying our gardens and farms we will provide more consistent year round harvests and avoid the boom or bust dilemma of many single crop systems. Many studies have shown a greater per acre cash return for these diverse systems in the long term than conventional systems.
These natural systems often referred to as agro-ecology, agro-forestry, food forests, or regenerative farming are not a new modern idea but have been practiced by cultures throughout the world since the beginning of time. Many of these traditional systems have been abandoned for the quick cash returns provided by conventional commodity farming. But there is still great hope for a bright future. Many damaged landscapes have been healed by these regenerative practices. A great example exists in the Loess Plateau in China where millions of acres of desertified land were turned back to beautiful productive farms, waterways, and forests through the dedicated application of these regenerative practices. You can see the results for yourself in the documentary Green Gold by John D. Liu. Another amazing example is the work of Ernst Gotsch in Brazil. Ernst helped to recover over 2,000 acres of dry deforested land in the Atlantic rainforests through agro-forestry practices. After 30 years of work experts have called Ernst’s land the most healthy and biologically diverse section of the Atlantic rainforest; it is producing some the world’s most valuable cacao and coffee beans. You can learn more about his work in the free documentary called Life in Syntropy. Both of these documentaries are available on Youtube or Vimeo.
Editor’s Note: Pictured above is the author Taylor Walker in home scale, multi-layered garden containing over 250 varieties of fruits and vegetables on a 0.5 acres.
Taylor Walker is an ecological designer, and educator, who is in Belize to research and write a book on traditional and modern agro-ecological systems.
Canopy Species or Climax Layer
Gliricidia, Madre de Cacao
Mid Level or Smaller Trees
Jujube (Chinese Plum)
Pitaya, Dragon Fruit