Posted: February 1st, 2023

Economic minerals and clay minerals in the soil

The mineral portion of the soil consists of various types of minerals. The mineral that directly comes from the rock is called a primary mineral such as pyrite. The primary mineral contains many different types of minerals. They have a differential ability to hold and react with other chemicals and minerals in the soil. Clay minerals that derived from the primary mineral. There are different types of clay minerals as well. Clay minerals that are weathered more and are older contain fewer minerals and nutrients. However, some young soil is very active and can hold a huge amount of nutrients. Young soil can also swell and shrink based on the minerals in it. This is because, in the young soil, the clay minerals are new and not old. In completely weathered soil, some of the minerals like the anatase, hematite, and gibbsite lead to the formation of oxides. These oxides are derived by intense weathering from the leftover metals. These have very little cation ex changeability and so does not contain many nutrients and minerals.

The crystalline structure of the soil:
The clay mineral possesses various building blocks. A few of them are pyramid-shaped or polyhedron which is called tetrahedral consisting of four triangular faces. Out of these four, three of them meet at the vertex of each other. They contain silicon in the center and four oxygen in each corner. They are octahedron with layers formed as sheets and contains eight faces. A combination of cations in the octahedron contributes to the uniqueness of the clay and it is covered by six different hydroxide or oxygen molecules. The structure of it is quite complicated but these layers organize together as a cake and help in determining the soil properties.

Minerals and nutrients in the soil:
There are around 17 nutrients and minerals that are essential for the plant to grow and reproduce. There are oxygen, carbon, hydrogen, potassium, phosphorus, nitrogen, magnesium, calcium, sulfur, potassium, iron, boron, manganese, zinc, copper, nickel, chlorine, and molybdenum. The category of nutrients that are essential for the complete life cycle of the plant is known as essential nutrients. The other category of nutrients that are not necessary for completing the life cycle but can enhance the growth of the plants are known as non-essential nutrients.

Macroelements are those needed in larger quantities. Phosphorus, potassium, nitrogen, magnesium, calcium. Microelements are needed in less amount. Copper, zinc, sodium, molybdenum are micronutrients.

The nutrients present in the soil should be available in a form that can be taken up by the plant roots. In the majority of the condition, the nutrients are absorbed in an ionic form from the water present in the soil. However, the minerals serve as the origin for the formation of many nutrients. Most nutrients of the soil are found in the crystalline form of secondary and primary minerals. To support the rapid growth of the plants, the weathering should happen slowly. For instance- apatite and feldspar are the finely ground minerals in the soil that rarely provides a sufficient amount of phosphorus and potassium at a rate good enough for good plant growth. This is because most of the nutrients remain attached to the crystals of the minerals.

The nutrients are accessible to the plants because the nutrients get adsorbed to the surface of soil organic matter and the clay colloids and this generates a more accessible reservoir for numerous plant nutrients. The soluble pool of the soil is replenished as the plant start taking up water and nutrients from the soil. The microbes in the soil decompose the soil organic matter and this mechanism is another way of the soil replenishing its soluble pool. This is very essential to supply the plants with sulfur, nitrogen, boron, and phosphorus.