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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1SOIL PROPERTIESThe various properties of soil include1. Color2. Texture3. Humus4. Soil structures2Color 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.3DIFFERENT 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.4FACTORS DETERMINING SOILCOLOUR Four main factors influence the colour of a soil:1. Mineral matter derived from the constituents of the parent material2. Organic matter3. The nature and abundance of iron4. Moisture content5INTERPRETATION 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.6DETERMINING 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.7Munsell Color ChartsHue = dominant spectral or rainbow color Red, Yellow, Blue, Green Number increases and the color is more brilliant as grayness decreases8Color Determination in the field ALWAYS USE MOIST SOIL Munsells color charts values:-1. Absolute black = 02. Absolute white = 103. Light soils hue value = 7 or more4. Medium soils hue value = 5 65. Dark soils hue value = 4 or less9MOTTLES 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.10Hums 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 water11 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 colour1213TEXTURERefers to the size of particles.Three types are:Sand (Large)Silt (Medium)Clay (Small)14SOIL STRUCTUREThe soil structures commonly seen are-1. Blocky2. Platy3. Massive4. Prismatic5. Granular151. 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.162. PLATY Large, thin beds.Plate-like & arranged in overlapping horizontal layers.173. MASSIVE Soil has no visible structure. Hard to break apart & appears in very large clods.184. 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.195. 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.2021


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