Elements are also called nutrients. "At least 16 elements, called plant nutrients, are considered necessary for optimum growth, development and food values in plants," according to a report by the Cook County (Illinois) Forest Preserve District. Soil analysis tests provide information about nutrient content of soil, which determines the nutrient content of food grown on it.
Elemental analysis of soil describes the content of a particular portion of soil in terms of macro-nutrients and micro-nutrients. These are the elements of soil. Macro-nutrients are nitrogen, phosphorus and potassium, needed in the largest amounts. Micro-nutrients are iron, manganese, copper, zinc, boron, chlorine and molybdenum, all essential for human nutritional health. Food grown on soil with inadequate organic matter does not have these important micro-nutrients.
The total biological activity of soil is known as the soil "foodweb." It consists of billions of small living beings that function together and create healthy soil, which creates healthy food. They include bacteria, fungi, protozoa, earthworms, nematodes and anthropods. They eat, grow and move through the soil, making it possible to have healthy food, clean water, clean air and moderated water flow.
The living soil foodweb is also responsible for detoxification of pollutants in the soil. The U.S. Environmental Protection Agency has determined that the living organisms in organic compost transform volatile and semi-volatile compounds that make soil unhealthy. Compost also binds poisonous heavy metal particles so they do not leach into water supplies.
Standard soil analysis tests give results in terms of nitrogen, phosphorus and potassium. Fertilizer recommendations for these elements are also given. Alternative soil tests concentrate on the total biological content of the soil. Test results are given in terms of the population levels of bacteria, fungi, nematodes, protozoa, earthworms and anthropods. The presence of these organisms determines the fertility of the soil. The National Sustainable Agricultural Information Service provides a list of both types of testing services (please see the Resource in this article).
Plants, animals and humans become diseased when they eat food inadequate in trace elements, also known as micro-nutrients. A 2007 study at the University of California at Davis reported that tomatoes grown on organic soil are higher in flavinoids, which create antioxidants. Antioxidants are a cancer preventative. Organic, sustainable growing practices focus on replenishing the soil with trace elements derived from natural sources.