Micronutrients. The nutrients contained in the soils are in various mineral and organic compounds

The content of trace elements in soils depends on their content in soil-forming rocks and from soil-forming processes.

Normal plant growth is due to the content of soil in available forms of ash elements and nitrogen. Usually plants are assimilated from soil N, P, K, S, Ca, Mg, Fe, Na, Si in sufficiently large quantities, and these elements are called macrocells, and B, Mn, Mo, Cu , Zn, Co, F are used in small amounts and are called trace elements. The most important of these are the elements without which the formation of proteins is impossible - N, P, S, Fe, Mg; Elements such as K, Cu, Mg, Na, affect the regulation of cells and the formation of various tissues of plants.

The nutrients contained in the soils are in various mineral and organic compounds, and their reserves usually significantly exceed the annual requirement. However, most of them are in a form that is not available to plants: nitrogen - in organic matter, phosphorus - in phosphates, iron, aluminum, calcium, potassium - in the absorbed state, calcium and magnesium - in the form of carbonates, ie E. In it soluble in water form. The process of assimilating plants by the elements of nutrition is due to exchange absorption. Forms of compounds and biological significance of chemical elements are different. Elements are part of the soil in the form of various chemical compounds that characterize the type of soil, and have different biological significance.

Humus, nitrogen, phosphorus and potassium are the most important for soil fertility. Determining the content in the soil of certain chemical elements and their forms of compounds is the task of chemical analysis of soils.

The content of humus in the upper horizons of soils of different types varies widely, but for each type and subtype of the soil it is quite stable and therefore a characteristic indicator. For other elements, along with their gross content (which indicates a degree of soil fertility), it is necessary to know the content of their forms by plants.