The foundations of a healthy system are built upon its soils. Soil is alive and if you want it to be healthy and productive you must provide it lots of organic matter and nutrients. Soil management at PrairieGreens Permaculture is a dynamic and ongoing process.
Unfortunately, previous management only applied fertilizers and harvested most organic matter from the system. Compounding the problems from fertilizer application were tillage and pesticide issues. These management blunders (known as the green revolution) had resulted not only in a dramatic reduction of carbon and fertility in our soils but also in the death of our soil fauna. Our soils no longer held water or nutrients as well as they should due to carbon loss. Nor could our soils feed the organisms that would normally compete with or predate soil pests. Our soils needed help.
To rehabilitate soils we planted a perennial polyculture of legumes, nitrogen fixing species, and forage grasses in target areas. Perennial polycultures have longer growing seasons, grow deeper roots, and are more productive than annuals; these factors result in more rapid and extensive soil rehabilitation. Our primary targets in soil rehabilitation are carbon (organic matter), nitrogen (from legumes), and soil fauna (recruited with biodiversity); once these elements are restored soil fertility and structure return as well. Time, sunlight, and biodiversity were our primary tools for soil rehabilitation.
After several years our soils no longer clump when wet or crack when dry. A shovel full of dirt no longer reveals a barren mineral dust but a vital conglomerate of soil particles and soil dwelling organisms. Several years of growth and decay have added tremendous amounts of carbon and nitrogen to our soils. The vast amounts of organic material that have entered the soil has improved its structure and water/nutrient holding and retention capacity. The same organic matter feeds a diverse soil fauna increasing system resilience to pests and disease.
The nitrogen in our fields are not the fossil fuel produced compounds that leach from the system; but instead part-of and bound-to organic molecules produced by legumes and other nitrogen fixing species. Since our system’s soils are high in carbon and the forms of nitrogen are complex they remain in the system longer. When nitrogen is fixed naturally in the system and retained there longer, efficiency is increased and pollution is decreased.
Perennial polyculture have restored our soil’s fertility but most of gains would be lost if we introduced pesticides, annual crops, and/or tillage to our management practices. Therefore we only minimally cultivate small fractions of our farm in strips. After a strip is cultivated we allow it to be recolonized by perennials and move on to a new area. What we save on fertilizers, pesticides, externalities, and fuel; far outweigh any “sacrifices” due to not cultivating all of our land.