1. Soils of India

As per ICAR, 8 types of soils

1. 1. Alluvial Soil – Flood plains, Very fertile, 2 types, Khadar <new alluvium, very fertile> and Bhangar <older, more kankery> <Hindi word khad is fertilizer so obviously khadar more fertile>
2. 2. Black cotton soil – also called Regur as they swell when wet and shrink on drying, high moisture retaining capacity, formed by solidification of lava of Deccan Trap, Black due to iron and Aluminum <titaniferous magnetite>, deficient in organic matters but rich in lime, potash, Mg, Al, Iron, Lime etc
3. 3. Red and Yellow soil – Red due to iron oxide, rich in iron, Mg, potash but poor in lime <contrast with black soil which is rich in lime>
4. 4. Laterite soil – In areas of alternate high rainfall and dry period, High rainfall washes away lime and silica <leaching>, iron and aluminium is left behind , Read in colour, excellent for tea, coffee, rubber, cashew
5. 5. Forest and Mountain soil – Forest i.e organic matter hence rich in humus which is less decomposed hence acidic soil, rich in organic matter but deficient in potash, phosphorous. Lime
6. 6. Arid and Desert soil – high soluble salts <capillary action> and phosphorus but deficient in organic matter
7. 7. Saline and Alkaline soil – Due to canal irrigation <salt left behind due to capillary action in dry areas> , unsuitable for agriculture, treated by irrigation with mixing lime and gypsum, Na and Mg cause salinity, Calcium alkalinity
8. 8. Peat and Marshy soil – accumulation of large amount of organic matter in waterlogged areas, highly saline and deficient in Phosphate and Potash, mainly in coastal areas

• Note 1- All Indian soils are deficient in nitrogen <any option that says rich in nitrogen would be wrong>
• Note 2 – All soils except very obvious forest and mountain soil poor in humus
• Note 3  – Forest soil is acidic, none other acidic
• Note 4– Black soil rich in lime while Red,laterite, forest soil poor in lime

• Discuss – Max area under which soil
• Discuss – Distribution of soils
• Discuss -Bhabhar, Tarai, Bangar and Khadar

2. Climate

1. Equatorial – In the ITCZ <what is ITCZ>, No seasons, Day and night 12 hrs everyday <simple naa seasons are due to tilt but no effect of tilt at 0 degree>, high temperature, high precipitation <>200 cm, convectional>, Soil is nutrient poor not rich <high rainfall leaching of nutrient, minerals>

2. Mediterranean -Only place with rainfall in winter and dry summers <in winters under rain bearing westerlies, summer trade winds due to shift of pressure belts>

3. British type climate -Cool temperate western margin <obviously Britain west>, westerlies throughout, frontal cyclones,

4. Desert – Hot deserts under subtropical high, horse latitude <sinking air, no rainfall>, Cold desert typically in temperate zones in the interiors of continent, rain shadow of high mountains, Cold current areas

• Discuss – upwelling v/s downwelling and effect on climate
• Discuss – Taiga Climate
• Discuss – Types of rains <convectional, orographic, cyclonic and frontal>

3. Theory of Plate Tectonics

1. Continental Drift theory of Alfred Wegener (1912) that continent ploughed through the oceans and once there was single landmass (pangea)
2. Then came convectional current and sea floor spreading theory by Hass to explain continental drift that seafloor itself moves as it expand through a central axis due to convection currents in the mantle
3. Plate Tectonics describe large scale motion of lithospheric plates <what is lithosphere?>
4. 7 or 8 major plates and large number of minor and micro plates 

3 types of plate boundaries,

1. 1.transform where plates slide past or grind past each other
2. 2 Divergent or constructive boundary – plates diverge from each other and new ocean floor is created
3. 3 Convergent or Destructive boundary – Plates collide, move towards each other

• Discuss – Driving forces for plate motion
• Discuss- Evidence in support of continental drift, seafloor spreading
• Discuss – Paleomagnetism, Lithosphere, Asthenosphere and various discontinuities

4. Plate Interactions

1. Plates can be Continental Plate <SiAL, FELsic, Granitic>, Oceanic <SiMA, Mafic, Basaltic> or mixed
2. Oceanic plates are denser hence subduct under continental plates <remember Wegener that Continet plough under oceans>
3. Transform Boundary – earthquakes , eg.- San Andreas Fault in California
4. Divergent or constructive – Mid Oceanic ridge, rift valley , Earthquakes, Volcanoes
5. Convergent or Destructive – when continental plates collide – mountain building and earthquake, no volcanoes as no subduction; when ocean – continental plates collide, oceanic plate subducts resulting in trenches, earthquakes and volcanoes, Ocean-ocean convergence, heavier plates subduct resulting in trenches, earthquakes and volcanoes and formation of mountain arc

• Note– Any movement at plates, earthquakes would occur
• Note- For volcanism, subduction is necessary hence at transform boundaries, continent-continent convergence no volcanism
• Discuss – Formation of island arcs in Indonesian Archipelago
• Discuss – No Volcanoes in Himalaya, alps but volcanoes in Andes and Rockies
• Discuss – Aleutian island and Ring of Fire