Here is a handout I created for the
course I teach on
permaculture and regenerative agriculture. I wanted to create something simple and memorable: a 10 commandments sort of list. Feel free to use it if you find it useful.
Ten Principles of Healthy, Fertile, Resilient Soil
1.
Carbon is the basis for soil health.
Regenerative agriculture is driven by the primary goal of increasing carbon in the soil through naturally occurring processes (or mimicking natural processes). In natural ecosystems (forests, prairies, savannah systems), carbon is cycled down into the soil profile to
feed soil biology and create topsoil. We regenerate denuded soils by accelerating these carbon cycles and natural systems.
2. Soil carbon feeds microbes, captures nutrients and holds
water.
Without soil carbon, microbial life (bacteria and fungi) will not thrive in your soil. The more carbon in your soil, the greater the number of microbes you have working in concert with plant
roots. Soil carbon grabs ahold of nutrients rather than let them wash away, and serves as a giant sponge to holds water within the soil profile. Inversely, synthetic fertilizers and other chemical inputs kill soil biology (bacteria and fungi) which leads to a collapse in the carbon cycle.
3. Building topsoil is a biological process.
Natural ecosystems are constantly adding carbon to the soil. We seek to mimic these natural processes in our soil management.
I. Plant roots pump liquid carbon down into the soil in the form of
root exudate( sugars and starches) to feed the bacteria and fungi that surround the root zone. 50-70% of a plant’s
energy goes to this because plants depend on the microbes these sugars attract and feed.
II. When plants die, their roots remain in the ground. In a low oxygen environment, they decompose slowly, and add their biomass to the soil.
III. Worms and biota feed on plant material (both on the soil surface as well as below ground) and then distribute that carbon down throughout the soil profile.
IV.
Compost is king. Use as a soil amendment or a mulch on the soil surface. No carbon
should ever leave your system if possible. Garden and
yard waste, food scraps, animal bedding and manure, and even house wastes (like paper and
cardboard) should all be turned into compost. Compost is rich in nutrients like N, K & P, but more important, is teeming with microbial life. Compost is a living soil amendment, adding billions of bacteria and microbes in every handful.
4. Armor the soil surface with biomass.
Mulch, mulch, mulch, and then mulch some more. In nature, every leaf drops to the soil below to create a natural blanket on the soil surface. Every broken stick or plant that dies, every pile of manure that an animal leaves behind, every trampled branch or stem, and ultimately, even dead bugs, birds and animals fall to the soil to nourish it. Either naturally or by bringing in bio mass like
wood chips, we keep a layer of armor on the soil at all times.
5. Keep a living root in the ground always.
Whether we are growing veggies, tree crops, grains or a cover crop, we seek to have something growing in our soil for as many months as possible. Often this will mean planting 3 or even 4 different times a year to assure that something is always growing. If there is no living root, we waste the sun’s energy and are not pumping root exudates into the soil to feed the microbiology.
6. Minimize or eliminate tillage.
When soil is tilled, soil aggregation is destroyed (thereby significantly decreasing infiltration of water and nutrients). Fungal networks are shredded and destroyed. Massive amounts of oxygen is introduced into the soil profile which in turn artificially stimulates a microbial bloom that consumes soil carbon. While a cleanly plowed field or freshly tilled garden looks nice, and in the short term appears to create light fluffy soil, once the natural biotic “glues” that hold the aggregates are destroyed and once the soil carbon has been consumed, the soil will compress and become hard and lifeless.
7. Capture every ray of sunlight.
Nature is
solar powered. Sunlight is free, abundant, and the only energy source we need. If there are no plants to capture and photosynthesize the sunlight, we waste this precious resource. Conversely, sunlight falling on bare soil will kill soil life by irradiating the microbes, heating the soil and evaporating moisture. Planting a diverse mix of broadleaf plants, grasses, and
trees will capture and convert as much energy as possible while protecting the soil below.
8. Capture and hold every drop of water.
Soils that are carbon rich are a giant sponge to infiltrate and hold tremendous amounts of water. Rain events are nitrogen events: rain water is nutrient dense (whereas
city water has chlorine and other chemicals). By mulching, digging swales, hugelkulture and using other water harvesting techniques, we assure that water does not run off our soil, nor evaporate carelessly.
9. Plant diversity is critical.
Its not
enough to just have a living root in the soil, but because every plant has a different chemical signature in their root exudates, we intermix a wide variety of plants in our gardens and agricultural systems. Multi-species cover crops, plant guilds, intercropping, crop rotation and even letting weeds grow are all ways to assure that a wide diversity of plants are living and dying on our
land, each contributing their unique contribution to biodiversity and microbial soil health. Attracting and sustaining diverse insect and bird populations requires a bio diverse ecosystem.
10. Animal integration.
In natural ecosystems, grazers, predators, birds, bugs and even humans all make a contribution to soil health. Soil biology takes on complexity and increases fertility when animals are introduced into your growing systems. Animals add their
urine and
poop, disturb of the soil, trample biomass down onto the soil surface to produce mulch, stimulate plant growth through grazing, and contribute significantly through the complex processes that occur in their digestive tract. They turn garden waste, plants and weeds into fertilizer, eggs and meat.
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