Topsoil is lost through erosion caused by natural processes and by industrial agricultural practices such as intensive plowing, monocropping and the overapplication of toxic synthetic products. “The rate of soil erosion now vastly exceeds soil formation,” according to the Center for Earth Leadership. Topsoil is the uppermost eight to 10 inches of earth. It takes 500 years of natural processes to create one inch of topsoil.
Topsoil sufficiency is vital because it is the layer of earth that produces the world’s food. When topsoil erodes, famine can follow. Topsoil is only as vital as the living organisms that it supports. One acre of living topsoil contains “approximately 900 earthworms, 2,400 pounds of fungi, 1,500 pounds of bacteria, 133 pounds of protozoa, 890 pounds of anthropods and algae, and even small mammals,” according to the National Sustainable Agricultural Information Service.
Topsoil is a living community that creates nutrients in food. The tiny living organisms in soil ingest decayed matter and exude nutrients that are taken up into vegetables and fruit crops. Fruit and vegetables need 17 nutrients for healthy growth. Tomatoes grown on nutrient-rich, organically managed topsoil have 79 percent higher levels of flavinoids, according to a 2007 study at the University of California at Davis.
Minerals are essential for good health. The mineral content of food is derived from the mineral content of the topsoil in which it is grown. Nutrients in food are created by the populations of living organisms in the soil. There has been an 82.70 percent decline in the magnesium content of an average apple in the last eight decades, according to analysis by the Nutrition Security Institute.
Topsoil Erosion Control
Topsoil can be conserved through the practice of sustainable agriculture and organic gardening. Industrial farms lose tons of topsoil from intensive tilling. Sustainable methods of topsoil conservation include no-till, low-till, mulching and planting cover crops. Crop residues are left on the land and less than 10 percent of the land is disturbed in planting. Home gardeners can use composting as a topsoil conservation method.
Synthetic nitrogen in fertilizer boosts plant growth while destroying the natural biological processes of soil. Insufficient, lifeless topsoil is created when the soil food web of biological processes is destroyed by nitrogen overload. Excessive nitrogen from synthetic fertilizers has been identified by the World Resources Institute as the primary cause of global pollution problems.