Geography of Soils Exam 2

Geography
Redoximorphic Features
Soil properties associated with wetness that result from the reduction and oxidation of iron and manganese compounds after saturation and desaturation with water.
Redox Concentrations
Zones of accumulation of Fe-Mn oxides in soil.
Redox Depletions
Zones of low chroma (
Reduction
The gain of electrons, and therefore the loss of positive valence charge, by a substance.  In some cases, a loss of oxygen or a gain of hydrogen is also involved.
Oxidation
The loss of electrons by a substance; therefore, a gain in positive valence charge, and, in some cases, the chemical combination with oxygen gas.
Anaerobic
When the O2 supply is virtually exhausted the soil environment is said to be anaerobic.  Slows down decomposition rates.
Oxygen…

Oxidized form =O2

Reduced form = H20

 

So, when things are reduced they are gley / low chroma as a result of being waterlogged.  When the soil is aerated better it is oxidized, and "more colorful".

Nitrogen…

Oxidized form = NO3 (nitrate)

Reduced forms = N20, N2, NH4

Carbon…

Oxidized form = CO2

Reduced form = CH4 (methane)

Specific Heat (of soil)
Dry soil = 0.2 cal/g
A reminder…
Study the handouts, look for temp patterns on the graphs….Good luck!

Leave a Reply

Your email address will not be published. Required fields are marked *