Tiêu đề SSAC 111 Definitions_compressed.pdf ✅

33.Soil Biology : Soil Biology is the study of microbial and faunal activity and ecology in soil. 34.Soil Erosion : Soil Erosion may be defined as the detachment, transportation and deposition of soil particles from one place to another under the influence of wind, water or gravity forces. 35.Land Capability Classification : Land capability classification is a system of grouping soils primarily on the basis of their capability to produce common cultivated crops and pasture plants without deteriorating over a long period of time. 36.Humus : Humus is complex and rather resistant mixture of brown or dark brown amorphous and colloidal substance modified from the original tissues or synthesized by the various soil organisms. 37.Humification : The process of decomposition of organic matter material in soil is called humification. Or Humification is a process of transformation of raw organic matter into humus. 38.Elluviations : Elluviations (wash out) is a process of removal of constituents by percolating water from upper layer to lower layer, this layer of loss called as elluviations. 39.CEC (Cation Exchange Capacity) : CEC is defined as the sum of positive (+) charges of the adsorbed cations that a soil can adsorb at a specific pH. Or The capacity of solid (clay) to adsorb and exchange cations is called cation exchange capacity. 40.Drainage : It is defined as removal of excess gravitational water from the soil surface or below the surface to create favourable condition for plant growth by providing surface and subsurface drainage. 41.Field Capacity : The percentage of moisture retains by soil in micro or capillary pores at tension of 1/3 atmospheres or 2.51 PF or 33 kpa is called field capacity. 42.Flocculation : The phenomenon of coalesce and formation of flocs is known as Flocculation. 43.Particle Density : The mass per unit volume of soil particles is called as particle density. Or The weight per unit volume of the solid portion of soil is called particle density. 44.Bulk Density : The oven dry weight of a unit volume of soil inclusive pore spaces is called bulk density. 45.Soil Classification : Soil specification is the systematic arrangement of cells into groups or categories on the basis of their characteristics. 46.Soil Survey : it is systematic examination, description, classification and mapping of soil of an area. Or It is a study and mapping of soil in their natural environment. 47.Soil Taxonomy : Soil taxonomy is a classification of soils according to natural relationships among the soil characteristics. 48.C:N Ratio : The ratio of the weight of organic carbon (C) to the weight of total nitrogen (N) in soil (or organic material), is known as C:N ratio.
49.Soil Aeration : The constant movement or circulation of air in the soil mass resulting in the renewal of its components gases is known as soil aeration. 50.pF : pF may be defined as the logarithm of the height in centrimetre of a water column that is necessary to produce desired suction. 51.Adhesion : 52.Cohesion : 53.Ion Exchange : Ion exchange is defined as a reversible process by which cations and anions are exchanged between solid and liquid phases between solid phase it in close contact with each other. For the exchange of cations and anions the term is used as cation and anion exchange respectively. 54.Adsorption : Adsorption is defined as facts by which an increased in concentration or accumulation of an ion species on a solid occurs due to ion exchange or other reaction. 55.Desorption : Desorption is fact by which the replacement or release of an absorbed ion species occurs. 56.Hydration : Chemical combination of water molecule with mineral is known as hydration. 57.Hydrolysis : It is a decomposition reaction as H+ ion of water tends to change place with the cations of mineral. 58.Luster : The reflection of light from the surface of mineral. 59.Strokes Law : The velocity of falling particle is proportional to the radius square and not to its surface. 60.Streak : It is the colour of the powder of mineral. Answer in One Sentence : 1. What is soil consistence? – Soil consistence is defined as “the resistance of a soil at various moisture contents to mechanical stresses or manipulations “. 2. What is Hue? – It is the dominant spectral colour. 3. Name the scientist who is known as the Father of Soil Science – V. V. Dokuchaev. 4. Name two reference books along with author’s used for SSAC 111 – ➢ ISSS. 2009. Fundamentals of Soil Science. 2nd Ed. Indian Society of Soil Science, New Delhi- 110 012. pp. 728. ➢ Das D. K. 2011. Introductory Soil Science, 3rd revised and Enlarged Ed, Kalyani Publisher, Ludhiana. pp. 645. 5. Give the mineral composition of marble – Limestone. 6. What is streak of mineral? – It is the colour powder of a mineral. 7. Name the cementing agent in soil structure – Silica, Lime and Iron oxide.