When soil is disturbed, carbon is released. Farmers use no-till methods to keep carbon in the soil. You can use no-till methods, too! If much of your garden is devoted to permanent plantings of native trees, shrubs, and perennials, you’re already practicing a form of no-till horticulture.
Cultivated soils have lost 50-70 percent of their original carbon stock, much of it oxidized upon exposure to air to become C02.