Soil fertility is the amount of macro- and micronutrients present in the soil.
Soil fertility refers to the amount of nutrients in the soil, which is sufficient to support plant life. To be fertile, soil needs macronutrients, which include nitrogen, potassium and phosphorous; micronutrients, which include sulfur, chlorine, copper, manganese, molybdenum, boron, iron, cobalt, magnesium, zinc and chlorine. It must contain organic matter and a relatively lowpH value. The soil must also contain micro- and macro-organisms and it must be well drained.
In desert gardens, particularly those in arid regions, chances are that most native soils do not contain all (or in some cases any) of the above characteristics. Arid soils are characteristically low in organic matter and have high pH values, making them highly alkaline and unsuitable for growing many plants. There are few micro- or macro-organisms living in the soil, helping to break down substances, and the soil is generally too well drained and incapable of retaining much moisture.
While these conditions are fine for xeric plants, and those that are adapted to such conditions, they are harsh for more temperate climate plants.
Desert soils can be amended by adding organic or synthetic fertilizers, organic material, compost, and topsoil to the mixture. Water-soluble fertilizers tend to pollute over time by adding unwanted salts to the soil and through runoff. Slow release fertilizers or organic fertilizers are much less harmful to the soil and to the environment.
