Soils NR 200. Unit 1. The Soils Around Us. What is soil?. Dictionary – The unconsolidated material that occupies the earth’s surface and supports plant life. Or perhaps: The link between the living and non-living. (The non-living supporting the living).
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Soils NR 200
A. Medium for plant growth
B. Important component of the hydrological system
C. Mother nature’s way of recycling organisms
D. A sphere for living organisms ie macro and micro organisms
E. Supporting foundations of our human made structures
1) the roots need O2 for respiration
2) organisms need O2as well
1) From once living organisms
2) Decaying and making their minerals available again
3) Improves water holding capacity
4) Humus is the longer lasting material that is responsible for this water holding ability, colloidal.
1)Needed to allow the plant to have as many leaves positioned to accept sunlight
2)Keep plant in place to receive water and minerals
1) Needed to allow for respiration
2) Needed for microorganisms to flourish
1)Almost all the water the plants need
comes from the soil
2)Also important for the microbial
action in the soil
3) Important for nutrient absorption
4) pH: the degree of alkalinity or acidity of the soil solution or soil
pH range - 1 – 7 – 14 a logarithmic relationship
Soil pH is simply the measurement of the H+ ion
1)The ability of the soil to insulate itself from the extreme hot and cold of the air above it.
2) Allows the roots to grow and an environment favorable to microorganisms
1)Only C,H and O are taken in by the plant from the atmosphere the other 13 are from the soil.N,P,K, Ca, Mg, S, Fe, Mn, Zn, Cu, B, Mo, and Cl?
A few to watch Ni, Co, Na and Si?
2)Root hairs are the plant structure responsible for bring in the nutrients and water.
3) The elements must be brought into the plant via ionic solution that is, ions dissolved in solution. These ions go into solution from the colloids in the soil. Pg 25
3) The plant obtains these minerals by:
a)Root interception -that is the root
grows into a new area and captures
the ionic solution.
b) Mass flow – soil water with ions moves into contact with the root.
c) Diffusion – ions move from areas of higher concentrations to areas of lower concentrations ie around roots.
IV. Soil Profile: Cross Section of the Soil Observed Vertically
i - undecomposed organic material
a – organic material highly decomposed
1) Best for nutrient holding, water capacity, micro-organisms
2) The most important soil profile for plant life
3) p – plowed or other cultivated disturbance (man made)
E – An area where the greatest eluvation (removal of clay, iron and OM) occurs, resistant materials such as quartz, sand and silts remain usually light in color.
m - cemented zone usually silicates or calcium
g - strong gleying
C – Parent material but broken down but not subject to the soil forming properties as the above solum (A&B) and not massive in structure as R
Sand:2 - .05 mm Silt:.05 - .002 mm Clays: less than .002 mm
Soil is the interaction of the lithosphere (rock), Atmosphere, Hydrosphere and the Biosphere (living organisms)
c) Waste disposal
d) building materials
3) Land use of the future????