Soil Fertility and Nutrient Management
Fertile soil is the foundation for a healthy landscape, and, therefore, a main focus for Permaculture Artisans. Our nutrient management strategies are rooted in the latest soil science; through a combination of short-, medium-, and long-term tactics, they activate and sustain a healthy nutrient cycle on the land. (More on that here. Link to learn/soil) Furthermore, we take into account the changes in use across a landscape. Certain techniques are better suited to smaller, high-use areas, for example, than large-scale ranches.
Regardless of the size or state of a landscape, we often start with a set of soil tests to establish the soil fertility baseline. At the most basic level, we test your soil’s mineral content and cation-exchange capacity, two fundamental indicators of soil health. Tests for soil structure, composition, and biological activities may also be used to understand the best methods for improving your soil fertility. If there is any suspicion of contaminants such as lead or cadmium specific tests can be performed to determine their levels. Soil color and smell, land-use trends and activities on neighboring properties are some of the factors we take into account to determine the right soil tests for a site. Once soil tests have been done and observations made, a customized soil-building plan can be created. Usually this means a re-mineralization of your soil with the appropriate amendments, use of non-till cultivation techniques, and the building up of organic matter over time.
A first step in building soil fertility is to inoculate the soil with the organisms and nutrients we want to see flourish. The application of compost tea is one of our preferred techniques to activate and sustain soil fertility. Its use during planting and regular feedings throughout the growing season can dramatically increase crop yields, disease resistance, nutrient uptake, erosion control, and decomposition of organic matter. Depending on the plant communities and overall state of soil fertility, different compost teas may be used (e.g., more fungal, or more bacterial). Permaculture Artisans will continually assess your landscape’s needs and advise accordingly on compost tea application rates and varieties. We use recipes from The Compost Tea Manual by world-renowned Soil Biologist Dr. Elaine Ingham in our tea-making operations. Over her illustrious 35-year career (and still counting!), Dr. Ingham has revolutionized our understanding of the soil food web and the mutually beneficial relationships that link all life on earth to soil. Let’s put this groundbreaking science to work building healthy soil on your land!
The use of cover crops is an intermediate step in nutrient management, providing both a medium- and long-term boost to soil fertility. Cover crops have the added benefit of helping to mitigate erosion. We select cover crops to perform a variety of functions, depending on the soil’s needs. For example, they can provide habitat and food for soil organisms, accumulate nutrients that might otherwise leach out of the soil, add nitrogen, unlock nutrients present in the soil but unavailable to soil organisms and the roots of other plants; and/ or break up compacted soil. In addition to plant selection, the way cover crops are used can be adapted to support the specific deficits in your soil’s fertility. For instance, deep-rooting cover crops are generally left in the landscape long enough to mature so their root systems reach farther down in the soil layers. On the contrary, quick-growing grasses may be “chopped and dropped” in place after only a few weeks to provide an influx of organic matter.
Planting for healthy soils
Plant selection also plays a vital role in soil fertility, particularly over the long term. Specific planting techniques incorporating nitrogen-fixing and mineral-accumulating species will continue to nourish and build the soil over time. A well-designed permaculture garden requires few or no external nutrient inputs after the plantings are complete and have matured, typically a period of 3 – 7 years.