Soil Science Lecture 10 after (midterm 2)

Phyotosynthesis

autotrophic transformation converting light energy into chemical energy useable by living organisms

Photosynthesis Chemical Equation

6CO2 + 6H2O →C6H12O6 + 6O2

The Carbon Cycle consists of

Co2 in plant tissue death to organic residues, Photosynthesis goes to animal tissue then organic residues, ???

Respiration in Carbon Cycle

Moves Organic residues and animal tissue to Co2

Combustion in Carbon Cycle

Fossil fuels to carbon

Herbivory in Carbon Cycle

organic residues tpo soil humus to animal tissue

Immobilization

herbivory, consumption and metabolism of plant material, eating organic source, animals and bugs/organisms

Carbon Nitrogen Ratio

how much carbon relative to N in organic material, every 10 units of C microbes need one unit of N

If there is a high C:N ratio then what do microbes do?

find another N source for balance or stop eating

What is considered a high C:N ratio?

30:1

Humus

conceptual mixture of organic substances but may not reflect reality

Fresh Organic Residue Functions and Decoposition

rapid decomposition, 1-2 years, nutrient release, food for microbes

Active Fraction OM Functions and Decomposition

slow decomposition, 15-100 years, some nutrient release, some CEC water holding capacity

Stabilized OM Functions and Decomposition

500-5,000, holds water and nutrients, maintains soil structure, sloe nutrient release 2-5% decomposes per year

Respiration (Decomposition) 

mineralization=conversion from organic to inorganic form