Soil Resources Flashcards

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1
Q

define soil

A

soil is the thin layer of loose mixture of small rock particles and rotting organic matter that covers the surface of the earth

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2
Q

process of soil formation

A

pedogenesis

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3
Q

study of soil and its associated factors

A

pedology

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4
Q

characteristics of fertile soil

A
  1. adequate amount of moisture
  2. sufficient depth to enable plants to grow their roots
  3. rich in nutrients
  4. contains organic matter
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5
Q

categories of soil

A
  1. In-situ (residual/sedimentary)
  2. ex-situ (transported soil)
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6
Q

in-situ soils

A

red soil, black soil, laterite soil, desert soile

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7
Q

example of transported soils

A

alluvial soil

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8
Q

Alluvial Soil

A
  1. formed by sediments brought down by rivers
  2. fine particles called alluvium
  3. aka riverine soil
  4. mixture of clay, sand, silt (loam)
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9
Q

where is alluvial soil formed

A

indus, ganga, brahmaputra
coastal in coastal plains and deltas of mahanadi, krishnam godavari, kaveri

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10
Q

two types of alluvial soil

A

bhangar and khadar

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11
Q

bhangar soil

A

old, composed of lime nodules (kanker),clayey composition

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12
Q

khader soil

A

light colour,
newer deposits,
more fertile as new layers of soil are deposited after monsoons

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13
Q

distributions of alluvial soil

A
  1. inland: indus, ganga, brahmaputra
  2. deltaic: ganga-brahmaputra delta, mahanadi, godavari, kaveri, krishna
  3. coastal: peninsular india, gujarat
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14
Q

GR: why does alluvial soil differ in colour?

A
  1. depth of deposition\
  2. texture of materials
  3. time taken for maturity
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15
Q

texture of alluvial soil

A

upper reaches: dry, course, porous, sandy. has clay and organic matter, large and non uniform soil matter (piedmont plains)
lower: particles are uniform and small, moist, depth of 500 m

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16
Q

minerals in alluvial soil

A

LFMPA: lime, iron, magnesia, potash, alumina
deficient in nitrogen and hummus
more alkaline in drier areas

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17
Q

crops on alluvial soil

A

rice, wheat, sugarcane, cotton, tobacco, gram, !!jute!!

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18
Q

name of black soil

A

black cotton soil/ regur soil/ lava soil (formed by denudation of volcanic rocks)

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19
Q

distribution of black soil

A

deccan lava tract

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20
Q

texture of black soil

A

fine textured
caleyey
high water retentivity
difficult to plough

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21
Q

minerals in black soil

A

LIMCAP: lime, iron, magnesium, calcium, alumina, potash
deficient of phosphorous, nitrogen, organic matter

22
Q

crops on black soil

A

cotton!!
jowar, wheat, linseed, gram, citrus, tobacco (moisture stored in subsoil)

23
Q

red soil

A

develops on old crystalline rocks
crystalline and metamorphic rocks of peninsular region break down to form red soil

24
Q

distribution of red soil

A

plateau region of peninsular india (TN, AP, Ktaka)
encircles black soil region on all sides
extends northwards along konkan coast

25
Q

colour of red soil

A

red due to iron oxide
brown or grey
yellow in hydrated form

26
Q

texture of red soil

A

porous, loose, aerated, shallow

27
Q

minerals in red soil

A

soluble salts
deficient of nitrogen, phosphorous, potassium, organic matter

28
Q

crops on red soil

A

dry farming like black soil
not fertile; responds to fertilizers
rice, ragi, tobacco, vegetables, groundnut, potatoes

29
Q

formation of laterite soil

A

formed due to atmospheric weathering of rocks under high rainfall and temperature with alternate wet and dry periods

30
Q

define leaching

A

process by which nutrients get percolated below the soil due to heavy rainfall, thus leaving topsoil infertile. also called desilication (lime and silica)

31
Q

two types of laterite soil

A
  1. upland laterites (hills and uplands)
  2. lowland laterites
32
Q

distribution of laterite soil

A

highland areas of peninsular plateau

33
Q

colour of laterite soil

A

red due to iron oxide, formed on leaching

34
Q

texture of laterite soil

A

coarse, soft, friable, porous

35
Q

minerals in laterite soil

A

acidic, iron oxide, potash
deficient in silica, lime, magnesium, nitrogen

36
Q

crops on laterite soil

A

does not retain moisture
tapioca, cashewnuts, tea, coffee
(with manuring) ragi, rice, sugarcane

37
Q

why is laterite soil not fertile

A
  1. low moisture retentivity
  2. high acidity
38
Q

define soil erosion

A

removal of topsoil cover by water, wind, human activitiesm

39
Q

methods of soil erosion by water

A
  1. sheet erosion
  2. rill erosion
  3. gully erosion
  4. leaching
  5. sea erosion
  6. stream bank erosion
40
Q

define sheet erosion

A

on gentle slopes, slow removal of thin layer of topsoil in low rainfall

41
Q

define rill erosion

A

when sheet erosion continues for long, silt-laden runoff forms finger-shaped rills of grooves over a large area.

42
Q

define gully erosion

A

in heavy rainfall, deep gullies are made on bare soils on account of water runoff

43
Q

methods of soil erosion due to humans

A
  1. loss of vegetation lead to sheet erosion, and topsoil is washed away
  2. deforestation
  3. uncontrolled grazing of domestic animals in upper slopes
44
Q

define saltation

A

wind moves soil particles 0.1- 0.5 mm in size in bouncing/hopping fashion

45
Q

define soil creep

A

wind moves soil particles greater than 0.5 mm by rolling

46
Q

define suspension

A

soil particles less than 0.1 mm are detached by suspension

47
Q

causes of soil erosion

A
  1. heavy population pressure on land
  2. nature of rainfall
  3. overgrazing
  4. bad farming techniques
  5. topography (steep slopes and heavy rain)
  6. deforestation
48
Q

regions of soil erosion in India

A
  1. badlands of chambal and yamuna rivers
  2. piedmont zone of western himalayas
  3. chotanagpur plateau
  4. tapi-sabarmati valley
49
Q

prevention of soil erosion

A
  1. terrace farming
  2. shelter belts/ wind breaks
  3. contour ploughing
  4. strip cropping
  5. dams
  6. plugging gullies
  7. planting trees
50
Q

define soil conservation

A

prevention of reduced fertility of soil caused by overusage, acidification, salinisation, contamination

51
Q

effects of soil erosion

A
  1. loss of fertile topsoil
  2. decreasing soil moisture
  3. increase in droughts and floods
  4. silting of river and canal beds
  5. landslides