SOILS.
Soil is a material composed of five ingredients — minerals, soil organic matter, living organisms, gas, and water. Soil minerals are divided into three size classes — clay, silt, and sand ; the percentages of particles in these size classes is called soil texture. The mineralogy of soils is diverse. The most common mineral in soils is quartz; it makes beautiful crystals but it is not very reactive. Soil organic matter is plant, animal, and microbial residues in various states of decomposition; it is a critical ingredient — in fact the percentage of soil organic matter in a soil is among the best indicators .Soil colors range from the common browns, yellows, reds, grays, whites, and blacks to rare soil colors such as greens and blues.
The actual amount of each of these depend on the type of soil. some soils are deficient in one or more of these, while there are some other that have varied combinations.
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🔸️ types of soil:
The Six Types of Soil. There are six main soil groups: clay, sandy, silty, peaty, chalky and loamy. They each have different properties and it is important to know these to make the best choices and get the most from your garden.
2.SOIL PROFILE:
Sorry consists of three layers are called horizons.,namely,A,B and C horizons.
A soil horizon is a layer parallel to the soil surface whose physical, chemical and biological characteristics differ from the layers above and beneath. Horizons are defined in many cases by obvious physical features, mainly colour and texture. Apart from these three layers ,some other layers might be present at some locations. moving from the top to bottom, various soil Horizons are as follows:
▪︎Horizon O: the O origin is a surface horizone that consists of organic materials at various stages of decomposition it is most prominent and forested Areas where there is accumulation of debris is fallen from trees.
• Horizon A: the A horizon is a surface horizontal that largely consist of minerals like sand, silt and clay. and with appreciable amount of organic matter. the organic materials get incorporated with mineral matter,nutrients ,and water ,which are necessary for the growth of plants. this horizon is predominantly the surface layer of many soil and Grassland and Agriculture land.
• Horizon E: it is a substance horizon that has been heavily leached. leaching is the process in which soluble nutrients are lost from the soil duty precipitation or irrigation. the horizontal is typically light in colour .horizon E is not present in all the soils .
• Horizon B: the B Horizon is a subsurface horizen that has accumulated from the decomposition of certain mineral that have leached from the layers above. Horizon B is a transition zone between horizon Aand horizon C and contains matter derived from below as well as from above, it has some organic material in it, although the mineral matter is noticeably weathered.
• Horizon C: it is the least weathered horizon. it is unconsolidated, which loose parent material. this layer is the first stage in the soil formation process.
• Horizon R: underneath the aforementioned soil Horizons as the rock, which is also known as the parent rock or the Bedrock .this arrangement of layer is also known as soil profile.
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3.CLASSIFICATIONS OF SOIL.
Classification of soils consists of the division of soils into classes based on their genetic, textural, chemical, mineralogical, physical, or geotechnical characteristics. The nature of the parent rock influences the composition of the resulting soil. The weathering processes and type and amount of transport before deposition, as in the case of sedimentary soils, affect the structure of the soils and their engineering properties. E based on texture the main soil type identify and Sandy ,clayey,silty and loamy. on the basis of colours ,soil type are red ,yellow ,black,etc. on the basis of Genesis ,colour, and composition ,.Soil has several meanings according to the professional perspective of the person who defines it. the soil of India have been classified into the following types:
🔸️Alluvial soil:
Alluvial soil are depositional soils, transported and deposited by river and streams, thus,are widespread in the Northern Plains and deltas of the east coast ,making up about 40% of the total area of the country.
These soils are formed differently than many other soils, which are made through the long process of rock transformation that often takes millennia.
Punjab ,Haryana ,Eastern part of Rajasthan, Gujarat, Uttar Pradesh ,Bihar ,West Bengal, Odisha , value of Krishna, Godavari and Kaveri have the soils.
Alluvial soils provide many functions, the greatest is serving as the earth’s kidneys. Alluvial soils remove sediments and nutrients flowing in the adjacent water. They can also remove other contaminants from rivers and improve water quality for downstream communities.
These are very fertile rich in potash and lime, but poor in Phosphorus and nitrogen. Thus,these soils are intensively cultivated by using nitrogen -rich fertilizers.
the colour of alluvial soil varies from light Grey to Ash grey. the soils shade depends on the depth of the deposition, the texture of the material ,and the time taken of attaining maturity.
In many places around the world there are distinctly different soil colors, chemical properties, and human artifacts buried in floodplains. These allow scientists to reconstruct human occupation and land use history. In modern urban areas, alluvial soils contain discarded garbage that has been carried in with flood waters and buried. The most recent deposits at the surface typically contain abundant plastics. Deeper deposits contain older manufactured materials like glass, brick, and stone. Therefore, alluvial soils also represent critically important areas for archaeologists and soil scientists to date human occupation.
Black soil are also known as regur soil or black cotton soil .these are formed from Deccan Lava ,and cover most of the Deccan Plateau ,which includes part of Maharashtra, Madhya Pradesh, Gujarat, and Andhra Pradesh. in total ,the soil cover 16% of the total area of the country.
Because of their high clay content, black soils develop wide cracks during the dry season, but their iron-rich granular structure makes them resistant to wind and water erosion. They are poor in humus yet highly moisture-retentive, thus responding well to irrigation. Those soils are also found on many peripheral tracts where the underlying basalt has been shifted from its original location by fluvial processes.
The black soil are generally clayey , Deep, and impermeable .these soil swell and become sticky when wet and shrink when dried. So during the dry season the soil develops wide cracks. there,occurs a kind of” self- ploughing”.The sifting has only led to an increased concentration of clastic contents.
Chemically ,black soil are rich in lime, iron, magnesia ,and Alumina. they also contain potash. however ,they lack of phosphorus, nitrogen, and organic matter .the colour of the soil ranges from deep black grey. the black colour is due to the presence of iron and magnesium. the black soil absorb moisture ,which evaporate from the soil at a read it very low rate .because of this character of slow absorption and loss of moisture, the blacks soil retains moisture for every long time . The moisture helps crops ,specially the rain fed Once ,to sustain even during the dry season.
