Introduction to soil science in the International Year of Soils of FAO - 2015

1. SOIL
Fundamental Concepts
Professor & Head,
Department of Soil Science and Agricultural Chemistry
College of Agriculture, Vellayani
Dr. N. Saifudeen

2. What is soil?
Dirt
Filth
Land
Earth

3. o Dirt is what you find under your fingernails.
o Soil is what you find under your feet.
What is soil?
What’s the
difference between
soil and dirt?

4. Think of soil as a
thin living skin
that covers the land on earth’s crust
Soil is an amazing substance!!

5. Air 25%
Mineral Matter
45%
Water 25%
Organic Matter 5%
SOIL
Component definition:
A complex mixture of mineral matter, organic matter,
water, and air.
and countless organisms.

6. Without life, there is no soil.
Living things haven't just made a home in the
soil on our planet.
Life actually made the soil as we know it.

7. o Those planets have plenty of rocks.
o Mars has windstorms that erode rocks into dust.
o Venus has an acid atmosphere that cooks rocks into
new chemicals.
o But there's still something missing…
oLife…….
There is no soil on Mars or Venus or Moon
How come?

8. Soil
o Soft
o Natural body
o Sustaining life (including plant growth)
o Dynamically changing
o At the earth surface

9. SOIL PROFILES
Dig down deep into any
soil, and you’ll see that
it is made of layers, or
horizons.
Put the horizons
together, and they
form a soil profile.
Like a biography, each
profile tells a story
about the life of a soil.

10. Soilis the Basisof theEcosystem
The living systems
occurring above and
below the ground
surface are determined
by the properties of the
soil. We often ignore the
soil because it is hard to
observe.

11. Soils PerformVital Functions
Sustaining plant and animal life
below and above the surface
Regulating and partitioning
water and solute flow
Filtering, degrading,
immobilizing, and detoxifying
Storing and cycling
nutrients
Providing support
to structures
Rain
RunoffSoil
Infiltration

12. SoilsSupportLife
Organism Types
bacteria
fungi
protozoa
nematodes
arthropods
earthworms
Roles & Benefits
decomposition
release nutrients
create pores
stabilize soils

13. Definitions, Byers, et al., Formation of Soil, 1938*
o Soils are natural media for the growth of plants.
They are mixtures of fragmented and partly or
wholly weathered rocks and minerals, organic
matter, water, and air, in greatly varying
proportions, and have more or less distinct layers or
horizons developed under the influence of climate
and living organisms…Soils are dynamic in
character …the product of the action of climate and
living organisms upon the parent material, as
conditioned by the local relief.
o *Yearbook of Agriculture

14. Definitions, Hillel, Introduction to Soil Physics, 1982
o The soil is a heterogeneous, polyphasic,
particulate, disperse, and porous system, in
which the interfacial area per unit volume can be
very large. The disperse nature of the soil and its
consequent interfacial activity give rise to such
phenomena as adsorption of water and
chemicals, ion exchange, adhesion, swelling and
shrinking, dispersion and flocculation, and
capillarity.

15. Definitions, Spangler & Handy, 1982, Soil Engineering
o Soils are natural materials which occur in infinite
variety over the earth and whose engineering
properties may vary widely from place to place
within the relatively small confines of a single
engineering project …
o The properties of soils are continuously changing as
the amount of moisture fluctuates and other
environmental influences vary… and may change
dramatically under load
o Soil is used as construction material …

16. Definition, Soil Science Glossary, SSSA
(ii) The unconsolidated mineral or organic matter on
the surface of the earth that has been subjected to
and shows effects of genetic and environmental
factors of: climate (including water and
temperature effects), and macro- and
microorganisms, conditioned by relief, acting on
parent material over a period of time. A product-
soil differs from the material from which it is
derived in many physical, chemical, biological,
and morphological properties and characteristics.

17. Soil Formation
Five factors that affect soil formation
Parent Material
Climate
Living Organisms
Relief (Topography)
Time

18. Parent Material
Igneous sedimentarymetamorphic
ROCKS

19. Weathering
Breaks down rocks to create Parent Material
It can be caused by Climate, water, or living things
Movement
of sediment and rock to new places.

20. 1. Physical weathering
The effects of climatic factors such as temperature,water,
and wind. Freezing and thawing are a major contributor.
Weathering is continuous

21. 2. Chemical weathering
a. changes the chemical makeup of rock and
breaks it down. Rainwater can dissolve
minerals.
b. Some minerals react with oxygen. Oxidation
further decomposes rock.

22. Weathering (cont.)
B. Weathering causes soil to:
1. Develop
2. Mature
3. Age

23. Soil Forming Processes
o Translocations
o Transformations
o Additions
o Losses

24. SOIL
o As a portion of the landscape: Collection of
natural bodies occupying portions of the earth’s
surface that support plants and that have properties
due to the integrated effect of climate and living
matter, acting upon parent material, as conditioned
by relief, over periods of time.

27. Soils Sustain Life
Soils Support Urban Life
Soils Support Agriculture
Soils Clean and Capture Water
Soils Support Buildings/Infrastructure
Soils Support Recreation
Soils are Living
Soils Support Health
Soils Protect the Natural Environment
Soils and the Products We Use
Soils and Climate
Soils, Culture, and People
Value of Soils
to our natural environment and society

28. Soils Support
Food Production….

29. We wanted
Green
Revolution

30. Food, Forest and Population….

31. Soil Management Affects Soil Quality
Soil Quality
Soil Test Kit

32. Why do we study soil?
What is the role of
Soil Science?

33. Decreasing capacity of natural resources

34. o Study of soil as a part of terrestrial ecosystem,
environment, and integrated Earth surface System;
o Study of soil by physical, chemical and biological
means and others;
o Study of soil in scales ranging from molecular to
pedosphere;
o Study of soil in interaction with water, air, biomes,
and humans, etc.
What is Soil Science?

35. Soil Science
o Soil - plant science: - ion uptake, soil fertility,
nutrient transport, bioavailability; food quality
o Soil-water science: water translocation, water
use efficiency; nutrient loading, drinking water quality
o Soil- air science: gas exchange, emissions,
GHG, Global change
o Soil – material science: soil mechanics or
dynamics, soil engineering;

36. Soil Science
o Soil – ecosystem science: soil ecosystems,
stability of ecosystem. Biodiversity and ecological safety
o Soil - landscape science: soil associations, land
use patterns, soil taxonomy, archeology ,etc
o Food Science and Nutrition
o Medicine & Health science:
o Archaeology

37. Role of Soil Science
o Basic discipline of natural sciences;
o Fundamental science of agricultural
sciences;
o Core science of environmental and
ecological sciences;

38. Role of Soil Science
Impacts in:
o Land use planning;
o Help solve food supply,
o Policy making - agriculture and
environment protection;
o Consultancy: standards, restrictions, etc.

39. What is soil?

40. Definition, Joffe, 1949, modified by Birkeland, 1999
o Soil is a natural body consisting of layers
(horizons) of mineral and/or organic
constituents of variable thicknesses,
which differ from the parent materials in
their morphological, physical, chemical,
and mineralogical properties and their
biological characteristics.

41. Definition, Soil Taxonomy, 2nd ed.
o Soil is a natural body comprised of solids
(minerals and organic matter), liquid, and gases
that occurs on the land surface, occupies space,
and is characterized by horizons, or layers, that
are distinguishable from the initial material as a
result of additions, losses, transfers, and
transformations of energy and matter or the ability
to support rooted plants in a natural environment.

42. A soil survey includes maps, descriptions, properties,
climate, and interpretations.
These are excellent sources of information
Soil Survey is a Scientifically-Based Inventory

43. Scientific Names for Soils Reduce Ambiguity
• Like plants and animals, soils are classified
• The system is called Soil Taxonomy
• The highest level is the soil order (12)
• The lowest level is the soil series, often a
place name
Soil Order Formative terms
Alfisols Alf from combination of al (aluminum) and f (ferrous) iron
Andisols Ando from Japanese term dark referring to dark volcanic ash
Aridisols Latin, aridies, dry arid
Entisols Ent meaningless, root recent
Gelisols Latin gelare, to freeze
Histosols Greek, histos, tissue
Inceptisols Latin, incepum, beginning, inception
Mollisols Latin, mollis, soft, mollify
Oxisols French oxide
Spodosols Greek spodos, wood ash
Ultisols Latin ultimus, last, ultimate
Vertisols Latin verto, vertical cracking

44. Gelisols: Frozen
Histosols: Organic, wet
Spodosols: Sandy, acidic
Andisols: Volcanic ash
Oxisols: Very weathered
Vertisols: Shrink and swell
Aridisols: Very dry
Ultisols: Weathered
Mollisols: Deep, fertile
Alfisols: Moderately weathered
Inceptisols: Slightly developed (young)
Entisols: Newly formed
The 12 soil orders in the
Soil Taxonomy system

45. The Unique Resource Base
Warm, humid, tropical region
High solar radiation, 365days
High rainfall (300 cm)
High biological activity and rich
biodiversity
Undulating topography
Altitude 3-5m bmsl to 2500 m amsl
Distinct climatic changes
5% water resources of India
Kerala State

47. COASTAL SANDY SOILS
Kadinamkulam series: Mixed, isohyperthermic Typic Ustipsamments

48. SOUTHERN LATERITE
Kalliyur, Thiruvananthapuram
Clayey, kaolinitic, isohyperthermic, Typic Kandiustult

49. NORTHERN LATERITES

50. HIGH HILLS

52. World Soil Day 2014: “Soils, foundation for family farming”
World Soil Day 2015: “Soils, a solid ground for life”
5 December

53. http://www.fao.org/globalsoilpartnership/iys-2015/en/
http://ec.europa.eu/environment/soil/scoping_en.htm

54. nsaifudeen@gmail.com