No-till agriculture, also known as no-till gardening, no-till farming or zero tillage, refers to techniques inspired by nature's own method of reproducing its species in the wild.
Seeds or pieces of a plant fall to the ground and, naturally — whether through rain, wind, water and/or animals — are protected by leaves, stubble and soil, waiting for the right moment to give rise to a new plant.
In a natural state of self-seeding, over the years the soil gains organic matter, life and fertility. However, from a human perspective, this natural method has some drawbacks: it isn't very productive (it isn't designed to feed the high number of humans the earth carries) and species reproduce where and when they want, not where and when we want. In response to this, humans decided to create the practice of agriculture in order to increase production and grow crops at the time and place deemed convenient.
This movement also reduced the need to live as hunter-gatherers and led to the creation of human settlements. However, while these goals have been achieved, and there are still places where a balance and harmony between nature and food production has been reached, for the most part a major mistake was made: things were done without observing and imitating nature, and we began to destroy it. Deforestation, erosion, desertification, pollution, loss of life, rising disease rates — the list of what conventional agriculture has caused goes on.
Soil fertility and ground cover
To propose solutions to this destruction, let's first reflect on a few things: soil fertility and ground cover. In a natural state, soils are fertilized by herds of animals passing through, in what's known as the "herd effect," where animals move together across a patch of land, feeding as they go, leaving manure and urine, and working these natural fertilizers into the soil through their movement and trampling.
At the same time, in this process, stubble, branches, leaves, seeds, fruit and other plant debris fall and become incorporated into the soil, whether through the animals' own activity, the wind, or rainfall. This becomes a layer of ground cover that later turns into food for the soil and nutrition for the species living in it. It's a perfect way to prepare soil. However, in our eagerness to do things without observing and learning from nature's wisdom, we decided to move in with burning, and then take a "great leap" with industrial agriculture based on chemical fertilizers, heavy machinery, pesticides and industrialized seeds.
A step that is definitely destroying the soil: heavy machinery causes compaction, creating a hostile environment for the microorganisms and organisms living in it; monoculture farming wipes out biodiversity; animals are kept penned up, preventing the herd effect; chemical fertilizers and pesticides kill all life in the soil; and significant biodiversity and seed adaptation has been lost due to planting purely commercial species. Finally, the worst of all actions has been exposing bare soil to make it look "clean," and deep tillage as a desperate measure to decompact what we ourselves have compacted. On top of that, this act releases the carbon the soil had worked so hard to capture.
No-till farming means planting over the previous crop's stubble without breaking the soil's structure.
This practice can be applied anywhere from a flowerpot to a large field with specialized machinery, but it's clear we'll need to make some initial effort before enjoying a beautiful layer of spongy, fertile soil. Here, from my own experience, are the methods that have worked well for me.
Planting pioneer species
This system involves starting to work a soil by planting pioneer species with adaptation mechanisms such as deep roots, nitrogen-fixing nodules and/or leaves that make the most of transpiration. It's a way of imitating what nature does in what's known as primary succession, when mosses and lichens arrive to begin forming soil on rock.
Our job here is to focus on discovering which species might do well given the site's conditions. In northeastern Brazil, I started working my soils with sugar cane and cassava, both well adapted to growing in sand and resistant to lack of water during the dry months. Once these species grow and activate soil life, I've been incorporating that organic matter to start with somewhat more demanding crops such as sweet potato, moving on later to beans and vegetables. It's like a planned succession. Another example for colder climates would be alfalfa, which penetrates the soil with its roots and also enriches it with nitrogen.
Planting green manures
Green manure means planting species that literally serve as "fertilizer" for the soil. The most recommended are legumes, though we can use whatever seems appropriate. These green manures can be cut once they've grown a little, before flowering and setting seed; they can be lightly worked into the soil or simply left as cover. Over that plant cover we can then plant some deep-rooted crops until we achieve well-loosened, fertile soil. This method works really well and is economical, but its drawback is the time it takes.
Adding a layer of compost or substrate
This option involves adding a good layer of compost or a well-prepared substrate, at least about 20 centimeters deep, over degraded soil, so that we can plant into an environment that's perfect for our crops. It's the easiest and fastest way to get started, but its drawback is the high demand for this input, which we'll need to produce at home or buy on the market.
Personally, I often take a shortcut known as minimal tillage, where I prepare the soil intervening as little as possible (no more than 20 cm) with a digging fork, a double-handled fork, or a hoe if it's extremely hard. Then I add plenty of organic matter such as bokashi, compost, worm castings, herbivore manure and charcoal. Finally I plant, and in the next cycle I only remove the crops I need, leave plenty of roots and stubble in place, and add fertilizer and mulch. This can be a good option for anyone still using conventional agriculture, as a transition path toward full no-till farming.
Whatever technique is used, it's important to apply a mulch-type soil cover that protects against compaction while also adding organic matter and nutrition. This cover helps nourish the soil, retain moisture, reduce the need for watering, and prevent the appearance of volunteer plants. You can use the previous crop's stubble, straw, sawdust, wood shavings, dry grass, leaves, and so on. Just be careful not to include seeds or plant material that could sprout.
Benefits
Adopting these practices, whether in small home gardens or large-scale farming, brings major benefits:
- Prevents soil erosion by avoiding unnecessary machinery use.
- Increases organic matter.
- Preserves and improves soil structure.
- Improves water infiltration and aeration.
- Increases moisture retention capacity.
- Reduces the appearance of weeds or volunteer plants.