What’s the difference between dirt and soil? The simple answer, dirt is dead and soil is alive! Soil is comprised of air, water, decayed plant residue, organic matter (living and dead organisms), and mineral matter (sand, silt, clay). Healthy functioning soil needs to be able to sustain and nourish plants, soil microbes, and beneficial insects. Healthy soils are porous, allowing air and water to move freely through them, and are often home to earthworms. A balance between the chemical and physical components of a soil community is important.
Chemically; monitoring the pH, not over applying nutrients, and paying close attention to the nutrients you apply is important. Physically; compaction and drainage problems can also be issues. A lack of pore space is often a result of compaction, which slows the proper movement of air and water. Mechanical influences, such as wheel traffic, usually have a greater influence on compaction than natural causes would, and sometimes the use of deep tillage on an annual basis can be more detrimental than beneficial.
Proper drainage prevents soil from becoming anaerobic or waterlogged, prevents microorganisms from going to sleep, and helps eliminate disease and nutrient deficiencies from showing up in crops. We can improve soil health by disturbing the soil as little as possible, growing different species of plants through rotations and a diverse mixture of cover crops, planting cover crops around our harvest to keep living roots growing in the soil for as much of the year as possible, and keeping the soil surface covered with residue year round.
Well managed, multi-species cover crops improve soil biology, increase soil life, increase organic matter, improve soil structure and fertility, increase water infiltration and water holding capacity, increase production, decrease cost, and increase profits. Growing more plants in a rotation increases biodiversity, and diversity above ground improves diversity below ground. Are we just growing crops or are we focusing on growing a soil biological community around the plant?
By Byron Currin, Vance County Soil and Water Conservation District