Q 1 – What are exogenetic forces?
Ans.The external forces are known as exogenetic forces.
Q 2 – What are endogenetic forces?
Ans. The internal forces operating from within the earth are known as endogenetic forces.
Q 3 – What is the degradation?
Ans. The wearing down of relief is known as degradation.
Q 4 – What is the function of endogenetic forces?
Ans. These forces continuously elevate or build up parts of the earth’s surface.
Q 5 – Name the various exogenetic elements.
Ans. Water, air wind, ice, etc. are exogenetic elements.
Q 6 – How is energy generated within the earth?
Ans. The energy within the earth is generated by radioactivity, rotational and tidal friction.
Q 7 – What is the effect of gravitational stresses?
Ans. They activate wave and tide induced currents and winds.
Q 8 – What is orogeny?
Ans. Orogeny is a mountain building process.
Q 9 – What causes earthquakes?
Ans. Orogeny, epeirogeny, plate tectonics cause earthquakes.
Q 10 – Name the denudation processes.
Ans. Weathering, mass wasting/movements, erosion and transportation are the denudation processes.
Q 11 – Name the different types of weathering.
Ans. Weathering is of three types:-
- Chemical,
- Physical,
- Biological weathering.
Q 12 – What are the important agents of weathering?
Ans. Frost, wind, heat, glacier and running water.
Q 13 – Name the two active factors of soil formation.
Ans. Climate and living organisms.
Q 14 – What do you mean by exfoliation?
Ans. It is the process of peeling off the outer layers from the main rock.
Q 15 – What is bad land?
Ans. An area dissected with gullies and ravines.
Q 16 – What is humus?
Ans. Humus is the organic matter of vegetable or animal organs in the soil.
Q 17 – How do organic soils develop?
Ans. Organic soils develop from the accumulation of plant residues that are preserved by the low oxygen environment of shallow and stagnant waters.
Q 18 – Name the primary factors responsible for the development of soils.
Ans. The primary factors responsible for the development of soils are parent material, climate, biota, topography and time.
Q 19 – What is eutrophication?
Ans. Enrichment of water with nutrients, primarily phosphorous, causing abundant aquatic plant growth is called eutrophication.
Q 20 – Define soil profile.
Ans. A vertical section of the soil through all its horizons and extending into the parent material is called a soil profile.
Q 21 – What is pedology?
Ans. The branch of science that deals with the study of soil are called pedology.
Q 22 – What is added to the saline soil to reduce its salinity?
Ans. Gypsum is added to the saline soil to reduce its salinity and make it useful for crops.
Q 23 – What are the mineral contents of laterites?
Ans. The mineral contents of laterites include aluminium and iron oxide,
Q 24 – What makes the soil alkaline?
Ans. Alkaline soils are formed in areas of low rainfall due to the accumulation or retention of lime.
Q 25 – Name the four soil-forming processes.
Ans. The four soil-forming processes are eluviation, illuviation, Teaching and chelation.
Q 26 – What does ICAR stand for?
Ans. ICAR stands for Indian Council of Agricultural Research.
Q 27 – Name eight soil groups as classified by ICAR.
Ans. They are alluvial soils, black soils, red and yellow soils, laterite, arid, saline, peaty, organic and forest soil
Q 28 – What are geomorphic processes? Describe briefly.
Ans. The endogenetic and exogenetic forces causing physical; stresses and chemical actions on earth materials and bringing about changes in the configuration of the earth’s surface are known as geomorphic processes. Diastrophism and volcanism are endogenetic geomorphic processes.
Q 29 – Distinguish between exogenetic and endogenetic forces.
Ans. Exogenetic forces: The earth’s surface is being continuously subjected to external forces induced basically by the energy (sun). These external forces are known as exogenetic forces.
Endogenetic forces: The forces originating within the earth from its interior are known as endogenic forces. They are responsible for building up and wearing down of the earth’s surface.
Q 30 – What is directional force and what is its role?
Ans. Gravity is a directional force. It activates the movements of matter and also causes stresses on the earth materials. Indirect gravitational stresses activate wave and tide induced currents and winds. Without gravity and gradients, there would be no mobility and hence no erosion.
Q 31 – What do you understand by oxidation?
Ans. When atmospheric oxygen combines with minerals of rocks (especially with iron) to form oxides, the process is known as oxidation, v Rocks get rusted due to the presence of air and water. The rocks begin to decay and crumble to a powder mass of brown dust.
Q 32 – What is carbonation?
Ans. Carbonation is the process in which rainwater gets mixed with carbon dioxide. It dissolves limestone, chalk and marble rock to form carbonates or bicarbonates with minerals. Calcium carbonates and magnesium carbonates are dissolved in carbonic acid.
Q 33 – What is weathering?
Ans., Weathering means the weakening or wearing down, breaking up, rotting and disintegration of rocks at or over the earth’s surface.
Q 34 – What is chemical weathering?
Ans. Chemical weathering is the decomposition of rocks by chemical methods. It results from the action of weak acids and gases like oxygen, carbon dioxide and hydrogen. Chemical weathering produces a chemical change in the minerals of rocks. High temperatures and humidity cause the rocks to decompose.
Q 35 – How does mass wasting take place?
Ans. The force of gravity acts constantly upon the soil and bedrock. At various places, the internal strength of these materials is sufficient to keep them in place. But when the ground surface is sloping, the force of gravity is directed down the slope parallel with the surface. Every particle has least same tendency to roll or slide downhill and will do so whenever the downslope force exceeds the resisting forces of friction and cohesion that tend to bind the particles to the rest of the mass.
Q 36 – How does biota help in soil development?
Ans. Biota is the collective term for the animal and plant life of a specific area as per the period of time. The decomposition of organic wastes and residues and the activities of living plants and animals have marked influence on soil development. Burrowing animals such as moles, prairie dogs, earthworms, ants and termites help soil development slowly by decomposing organic matter and forming weak acids that dissolve minerals faster. The roots of living plants and decomposed plant material release weak organic acids that help in weathering and soil development.
Q 37 – What is the pH value of soils?
Ans. ‘pH’ value means ‘potential hydrogen’, the standard measure of activity or Alkalimists in the soils. It is based on the activity of hydrogen ions in a litre of a solution, expressed in gram per litre. The pH value range from 0 to 14.0. Neutrality is at 3.0. Numbers lower than neutrality signify increasing acidity and higher numbers increasing salinity. Knowledge of the pH value of the soil under cultivation is most important in agriculture and horticulture.
Q 38 – What is saline soil?
Ans. Because of the dry climate and poor drainage conditions, this soil acquires more salt. It is widespread in western Gujarat (Rann of Kutch), deltas of the east coast and Sunderban areas of West Bengal. Gypsum diminishes the salinity of soil and makes it useful for drops.
Q 39 – Distinguish between chelation and leaching.
Ans. Leaching is the downward movement of material from a soil horizon in solution.
Chelation is also the downward movement of material, similar to leaching, but under the influence of organic complex compounds.
Q 40 – Discuss the role of topography in soil formation.
Ans. The topography influences the soil formation through its relationship with relief, water and temperature. Steep hillsides have thin soil cover because of surface runoff that results in the erosion of the surface. On the other hand, gentle hillside preserves appreciable soil overdue to the luxuriant vegetation and sufficient water passing in vertically to deeper levels. The land-locked depressions receive a high amount of runoff water that favours appreciable vegetation cover but slower decomposition because of oxidation deficiency. This results in the formation of soil that is rich in organic matter.
Q 41 – How many essential elements are required by plants?
Ans. Plants need at least 16 essential elements. They are carbon, hydrogen, oxygen, phosphorus, potassium, nitrogen, sulphur, calcium, iron, magnesium, boron, manganese, copper, zinc, molybdenum and chlorine.
Q 42 – How are the exogenetic earth processes driven?
Ans. Exogenetic earth processes are the external processes that are driven by solar energy. They act through the atmosphere and oceans where air and water come in contact with the lithosphere.