Properties Of Soil | Chemistry | Environmental Chemistry | Presentation | By: Faizan Tanoli

Download Properties Of Soil | Chemistry | Environmental Chemistry | Presentation | By: Faizan Tanoli

Post on 13-Apr-2017

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  • SOIL PROPERTIES

    The various properties of soil include

    1. Color

    2. Texture

    3. Humus

    4. Soil structures

    2

  • Color is the foremost physical

    property that can be seen with

    naked eye and is useful in

    interpretation of valuable insight

    into the soil environment, thus it

    can be very important in

    assessment and classification of

    soil.

    3

  • DIFFERENT SOIL COLORS

    The most influential colours in a well drained soil are white, red, brown and black.

    White indicates the predominance of silica (quartz), or the presence of salts.

    Red indicates the accumulation of iron oxides.

    Brown and black indicate the level and type of organic matter. A colour triangle can be used to show the names and relationships between the influential colours.

    4

  • FACTORS DETERMINING SOIL

    COLOUR

    Four main factors influence the colour

    of a soil:

    1. Mineral matter derived from the

    constituents of the parent material

    2. Organic matter

    3. The nature and abundance of iron

    4. Moisture content

    5

  • INTERPRETATION USING

    SOIL COLOUR

    If we understand what determines soil colour,

    then we can use colour to make some

    inferences about, history, chemistry and

    hydrology.

    For example, an obvious change in colour

    between horizons is a real indication of

    changes in soil properties which are the result

    of biological activity, water movement and

    weathering.

    6

  • DETERMINING SOIL

    COLOUR

    Soil colour should be determined on moist surfaces of freshly broken (not sliced) soil samples.

    Like any other soil property, colour must always be observed throughout soil profile, paying special attention to the differences between soil horizons. Colour characteristics such as mottle size, percentage and contrast should be observed and recorded.

    A system that uses specially printed colour charts (Munsell Soil Colour Charts) gives an international standard. It divides colour into wavelength, lightness, and colour saturation.

    Where a Munsell Chart is not available, simple names as listed in the triangle can be used.

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  • Munsell Color ChartsHue = dominant spectral or rainbow color Red,

    Yellow, Blue, Green

    Number increases and the color is more brilliant as

    grayness decreases

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  • Color Determination in the

    field

    ALWAYS USE MOIST SOIL

    Munsells color charts values:-

    1. Absolute black = 0

    2. Absolute white = 10

    3. Light soils hue value = 7 or more

    4. Medium soils hue value = 5 6

    5. Dark soils hue value = 4 or less

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  • MOTTLES

    Spots of different colors in the soil

    Generally indicate that the soil has periods

    of inadequate aeration each year

    Usually rust colored

    Bluish, grayish, & greenish subsoils with or

    w/o mottles = indicate longer periods each

    year of waterlogged conditions &

    inadequate aeration.

    10

  • Hums

    The term was coined in17901800; (< Latin: earth, ground)

    Dark brown or black organic

    substance made up of decayed plant

    or animal organic matter, that

    provides nutrients for plants and

    increases ability of soil to retain water

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  • In soil science, humus refers to any organic matter that has reached a point of stability, where it will break down no further and might, if conditions do not change, remain as it is for centuries. Humus significantly improves the structure of soil and contributes to moisture and nutrient retention.

    In agriculture, humus is sometimes also used to describe mature compost, or natural compost extracted from a forest or other spontaneous source for use to amend soil. It is also used to describe a topsoil horizon that contains organic matter

    Humus also controls the colour of soil higher the humus

    content darker is the soil colour

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  • TEXTURE

    Refers to the size of

    particles.

    Three types are:

    Sand (Large)

    Silt (Medium)

    Clay (Small)

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  • SOIL STRUCTURE

    The soil structures commonly

    seen are-

    1. Blocky

    2. Platy

    3. Massive

    4. Prismatic

    5. Granular

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  • 1. BLOCKY

    Particles cling together in angular aggregates.

    Typical of soils with high clay content.

    Typical of B horizons.

    beds are large about 5 to 50 millimeters.

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  • 2. PLATY

    Large, thin

    beds.

    Plate-like &

    arranged in

    overlapping

    horizontal

    layers.

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  • 3. MASSIVE

    Soil has no visible

    structure.

    Hard to break

    apart & appears

    in very large

    clods.

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  • 4. PRISMATIC Prismatic structure are

    bounded by flat to

    rounded vertical faces.

    Units are longer vertically

    and top of the prisms are

    normally flat.

    It is commonly found in B

    horizons.

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  • 5. GRANULAR Is the best for most

    plants.

    Particles cling together

    to form rounded

    aggregates.

    It is commonly found in

    A horizons.

    Beds are small usually

    between 1 to 10

    millimeters.

    20

  • 21

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