soils

• soil - purpose of providing the basic needs of organism and

  support life on earth.
• soil - important in food production , base of infrastructures , and habitat of living organisms.
• igneous rocks - originated from solidified lava or molten rocks
• intrusive rocks - solidify before reaching surface; can also be formed inside the volcano ; solidified inside the Volcano
• extrusive rocks - solidified at the surface/ground
• Sedimentary - rocks formed from sediments (existing rocks, living organism , mineral particle
• Constituents of Soils

  45% - minerals

  25% - water

  25% - air

  5% - organic matter
• clastic rocks - made from clasts/fragments of previously existing rocks.
• BIOGENIC - formed when a previously living organism organic matter was combined to inorganic compound (mineral/s) the cemented or petrified through time.
• chemical rocks - build up of minerals Minerals (precipitation) which dissolved (soluble) in H2O
• Metamorphic rocks - formed due high temperature and pressure , particularly in the mantle.

  subjected to "metamorphism"
• minerals - building blocks of rocks
• mineral - inorganic substance w/ more/less definite chem. composition
• Primary mineral - persist from original rocks
• Secondary mineral - originated from chemical weathering of least resistant primary mineral;
• soil texture- permanent property of the soil; can be changes through time via chemical weathering
• soil profile - vertical section of the soil consisting of unique horizons.
• soil horizon - horizontal layer in the profile
• texture - refers to the relative amounts of the different particle size fractions or separates in the soil
• The Munsell color system is means to visually identify and match color using a scientific approach.
• hue - is the color such as red, green, blue, etc.
• Value - how light or dark a color is. In the Munsell system, value is indicated with a number, i.e. 2, 4, 6 and so on.
• chroma - how weak or strong a color. In the Munsell system, chroma is indicated with a number, typically in the range of 2-14 (upwards of 30 for colors in the fluorescent family).
• sand - is loose and single grained.
• sandy loam - is a soil containing much sand but which has enough silt and clay to make it somewhat coherent.
• loam - a soil having a relatively even mixture of different grades of sand and of silt and clay. It is mellow with a somewhat gritty feel yet fairly smooth and slightly plastic.
• silt loam - a soil having a moderate amount of the fine grades of sand and only a small amount of clay, over half the particles being of the size called “silt.”
• clay loam - loam is a fine-textured soil that usually breaks into clods or lumps that are hard when dry.
• soil structure - overall architecture of a soil defined by the assemblage of structural units, which it contains.
• aggregates - Single particles when assembled appear as larger particles.
• structureless - has no observable aggregation or no definite orderly arrangement of natural lines of weakness
• Massive structure (coherent) where the entire soil horizon appears

  cemented in one great mass
• Single-grain structure (non-coherent) where the individual soil particles

  show no tendency to cling together, such as pure sand;
• weak structure - is poorly formed from indistinct aggregates that can barely be observed in place.
• moderate structure - well formed from distinct aggregates that are moderately durable and evident but not distinct in undisturbed soil.
• strong structure - well formed from distinct aggregates that are durable and quite evident in undisturbed soil.
• granular and crumb structures - individual particles of sand, silt and clay grouped together in small, nearly spherical grains.
• Blocky and subangular blocky structures - are soil particles that

  cling together in nearly square or angular blocks having more or

  less sharp edges.
• Prismatic and columnar structures - are soil particles which have

  formed into vertical columns or pillars separated by miniature, but

  definite, vertical cracks.
• Platy structure - is made up of soil particles aggregated in thin

  plates or sheets piled horizontally on one another.