which is the most important fertile soil of India ? explain the characteristics of this type of soil
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Answer:
alluvial soil
The most fertile alluvial soil is found in the Ganga valley, where it is deposited by river Ganges. These soils cover almost 35-40% of the region of India. These soils are rich in minerals especially potash.
Composition and Characteristics of soil.
The scientific study of soil is called pedology. Soil is composed of both organic and inorganic matter, and it is essential for life on earth to exist. The soil type that i have studied is brown earths. Brown earths are the most common soil type in Ireland and are very fertile. Soils are a composition of mineral particles 45% , organic matter 5% , air 25% , and water 25% .
Mineral Particles:
Mineral particles are the largest ingredient and make up approx 45% of soils . They are the original rock that got broken down by weathering and erosion to form the basis of soil. The type of rock that was broken down to form it is called the parent rock. The broken down rock produces minerals such as calcium, phosphorus, and potassium in the soil on which the plants feed. The parent material influences the soil colour, depth, texture and ph value
Organic Matter:
Organic matter is decayed vegetation that is broken down by micro organisms in the soil to form humus . Humus is a dark jelly like substance that binds the soil together and improves its texture. It increases the soils ability to retain moisture. Brown earths develop in area of deciduous woodland where there is an abundance of plant litter available to decay. Brown earth soils are also found where temperatures average zero for less than 3 months of the year and rarely exceed 21 degrees. These conditions allow for microorganisms to thrive. The colour of the soil is an indication of the amount of organic material it contains with darker soils having more organic content. Humus is plentiful in brown earths
Air and Water:
Air is vital for the survival of micro-organisms and without theses, there would be a shortage of humus. Brown earths have a granular structure which allow for good aeration. Plants cannot survive without water present in the soil .Mineral particles are soluble in water and the roots of plants can only absorb the nutrients of them after they have been dissolved
Characteristics of brown earths :
Brown earths are usually 2 metres deep and have 4 horizons . The A horizon has a thick layer of dark humus. There is a plentiful supply of micro organisms which mix the soil well and leave no distinct boundary between the A and B horizons. The B horizon is similar but with a lighter brown colour. The C horizon has a n accumulation of clay and broken down rock. The bottom layer is the bedrock
Brown earths are fertile and very suitable for agriculture. Their suitability for agriculture are due to their characteristics of good texture, dark colour, and ph value .
Texture:
Texture is how a sol feels when you touch it. The proportions of sand silt and clay determines the soils texture. The texture determines how well moisture and roots can penetrate the soil and how well excess moisture can drain away. The ideal combination for soil texture is roughly 40% sand, 40% silt, and 20% clay creating what is known as a loam soil. Brown earths fall into this category. They have a well-developed crumb structure which allows water air and organisms pass through it easily, and roots can spread out in it easily. Water retention is good as it is soaked up by the crumbs of the soil and nutrient retention is good also. They also have good drainage and aeration properties. Loam soils such as brown earths are ideal for cultivation
Colour:
Lighter coloured soils deflect sunlight while dark soils absorb more light. This allows the soil to heat up much more quickly and encourages seed germination and crop growth, Heat is also important in the humification process. Brown earths have a high humus content which makes it a darker soil and thus supports good crop growth
PH Value:
PH scale measure the acidity of a substance. The ideal PH value for agriculture is 6.5 which is slightly acidic. A soil which is too acidic lacks calcium and potassium which are essential for growth and has low levels of organisms which are vital for humification. Soils which are quite acidic are peaty soils which have a ph value of less than 4and are found mainly in the mountainous areas of the west. They have suffered from leaching and tend to be waterlogged also. Brown earths have a ph value of between 5 and 7, ideal values that are known to be very fertile supporting a wide variety of plant life