Mmmmmmm Soil

1
Mmmmmmm Soil
I turn poo into soil. Im important
2
Ashes to ashes, dust to dust
Rock erodes into soil adding minerals.
3
Soil and Decomposers
4
The Soil System

• Soil is a complex mixture of eroded rock, mineral
  nutrients, decaying organic matter, water, air
  and billions of living organisms (microscopic
  decomposers).

5
Soil formation is a slow process

1. Weathering of rock (mechanical).
2. Deposition of sediments by erosion (mechanical).
3. Decomposition of organic matter in dead organisms
   (chemical).
4. Especially slow in dry areas like Wyoming.

6
A Soil Profile
7
Fungus decomposes dead organic matter into
smaller parts (and eventually soil).
8
Mature soils are arranged in a series of zones
called SOIL HORIZONS

• O HORIZON freshly fallen and partially
  decomposed leaves, twigs, animal waste. You can
  find fungi and other organic materials.
• A HORIZON porous mixture of partially
  decomposed organic matter (humus) and some
  inorganic mineral particles.

9

• B (subsoil) and C (parent material) HORIZON
  contain most of the soils inorganic matter,
  broken-down rock.

10
Rainforest Soil Profile
11
Giant crack in Wyoming
12

• These top two layers are most fertile, have the
  highest concentration of organic matter, and
  contain large amounts of living organisms.

13
Soil Content

• Clay (very fine particles)
• Silt (fine particles)
• Sand (medium-size particles)
• Gravel (coarse to very coarse particles)
• SOIL TEXTURE is determined by the relative
  amounts of the different types and sizes of
  mineral particles.

14
(No Transcript)
15

• Soil texture helps determine SOIL POROSITY, a
  measure of the volume of spores or spaces per
  volume of soil and the average space between
  those spaces.
• INFILTRATION is the downward movement of water
  through soils.
• As the water seeps down, it dissolves various
  soil components in upper layers and carries them
  down to lower layers in a process called
  LEACHING.

16
SOIL PERMEABILITY is the rate at which water and
air move from upper to lower soil layers.
17
Properties of Soils with Different Textures
Texture Nutrient Capacity Infiltration Water-Holding Capacity Aeration Workability
Clay Good Poor Good Poor Poor
Silt Medium Medium Medium Medium Medium
Sand Poor Good Poor Good Good
Loam Medium Medium Medium Medium medium
18
Pathway of plant nutrients in soil.
19
EROSION a huge soil problem
20

• Soil erosion is the movement of soil components,
  especially surface litter and topsoil.
• The two main agents of erosion are wind and
  flowing water.
• Loss of plant cover by farming, logging,
  construction, overgrazing by livestock, off-road
  vehicles, deliberate burning of vegetation and
  other activities leave soil vulnerable to erosion.

21

• Two major harmful effects of soil erosion
• Loss of soil fertility and its ability to hold
  water
• Runoff of sediment that pollutes water, kills
  fish and shellfish, and clog irrigation ditches,
  boat channels, reservoirs, and lakes.

http//www.wildmadagascar.org/kids/20-environment-
deforestation.html
22
(No Transcript)
23
(No Transcript)
24
The Threat of Soil Erosion

• "The threat of nuclear weapons and man's ability
  to destroy the environment are really alarming.
  And yet there are other almost imperceptible
  changes - I am thinking of the exhaustion of our
  natural resources, and especially of soil erosion
  - and these are perhaps more dangerous still,
  because once we begin to feel their repercussions
  it will be too late." (p144 of The Dalai Lama's
  Little Book of Inner Peace 2002, Element Books,
  London)

25
Desertification is the enlargement of deserts
through human activities.
Desertification in China is affecting 2.62
million square kilometers of land.
http//news.bbc.co.uk/2/shared/spl/hi/pop_ups/03/a
sia_pac_desertification_in_china/html/1.stm
26
What are the causes and consequences of
Desertification?
Desertification in the Mongolian Desert
(China) http//www.youtube.com/watch?vivcMMPzmKkY

27

• SALINATION
• Irrigation water contains small amounts of
  dissolved salts.
• Evaporation and transpiration leave salts behind.
• Salt builds up in soil.

28
Salinized Field in California
29

• WATERLOGGING
• Precipitation and irrigation water percolate
  downward.
• Water table rises.

Both result in stunted plant growth, lower crop
yields, dead plants and ruined land.
30
Soil Conservation involves reducing soil erosion
and restoring soil fertility.
31
Soil Conservation Measures

• Soil conditioners (use of lime and organic
  materials)
• Wind reduction techniques (wind breaks, shelter
  belts, strip cultivation)
• Cultivation techniques (terracing, contour
  plowing)
• Efforts to stop plowing of marginal lands

32
Soil Conditioning Why Does Soil Become Acidic?

• Soil can become acidic. Why?
• Acid Rain
• Bacteria decomposing organic material in soil
  release carbon dioxide when they breath..this
  reacts with water to produce carbonic acid making
  soil more acidic.
• Nitrification of ammonium ions to nitrates
  increases acidity
• Removal of basic ions through leaching increases
  acidity of top soil

33
(No Transcript)
34
How do Soil conditioners work?

• Soil conditioners include lime, limestone, ground
  chalk or organic materials such as straw or green
  manure.
• Conditioners are basic (pH 7-14) and help to
  NEUTRALIZE the acidity of the soil.
• Lime also helps clay particles to stick together
  making larger particles, increasing aeration, and
  drainage.

35
Why is maintaining a certain soil pH important?
36
Windbreaks or shelterbelts of trees reduce wind
erosion, help retain soil, supply wood for fuel,
and provide habitats for birds, pest-eating and
pollinating insects, and other animals.
37
Organic Vineyard (Cecchin) in Mendoza, Argentina
with a natural windbreak grown around the
perimeter of the field.
38
Contour planting and strip cropping each row
acts as a small dam to help hold soil and slow
water runoff.
39
Terracing retains water for crops at each level
and reduces soil erosion by controlling runoff.
40
The terraced Rice Fields of Northern Vietnam
41
Northern Vietnam Again an Example of Contour
Planting
42
Alley cropping or agroforestry several crops are
planted together in strips or alleys between
trees and shrubs that can provide fruit or
fuel-wood, shade, help retain and slowly release
soil moisture, and fodder for livestock.
43
Trees planted at the end of each row act as
natural wind breaks, slowing the wind down to
decrease erosion. -Mendoza, Argentina
44
At the organic vineyard olive tress are planted
to provide protection from wind and flowers are
planted at the end of each row to attract
pollinating insects. -Mendoza, Argentina
45
Advantages and disadvantages of using
Conservation Tillage.
46
Soil Restoration

• Organic fertilizer

• Animal manure

• Green manure

• Compost

• Crop rotation

• Commercial inorganic fertilizer

47
Definition of Green Manure

• Crop grown and plowed under for its beneficial
  effects to the soil and subsequent crops, though
  during its growth it may be grazed. These crops
  are usually annuals, either grasses or legumes.
  They add nitrogen to the soil, increase the
  general fertility level, reduce erosion, improve
  the physical condition of the soil, and reduce
  nutrient loss from leaching. They are usually
  planted in the fall and turned under in the
  spring before the summer crop is sown. See also
  cover crop.