Soils Final II

Question 1

What is Organic Matter?

Answer 1

All the Carbon based Biomass generated from organisms that inhabit sub-surface, surface, and/or soil interface environments and are produced directly and/or indirectly from soil and/or atmospherically derived nutrients and energy - either solar or otherwise

Question 2

What are plants primarily composed of?

Answer 2

Cellulose Compounds

Question 3

Describe and Name some Macronutrients

Answer 3

• What the Plant requires in larger values
• Nitrogen
• Phosphorus
• Potassium
• Calcium
• Magnesium
• Sulphur
• Hydrogen
• Carbon
• Oxygen

Question 4

Describe and Name some Micronutrients

Answer 4

• Plants require less of these elements
• Chlorine
• Boron
• Iron
• Manganese
• Zinc
• Copper
• Nickel
• Molybdenum

Question 5

Define what these nutrients do

Answer 5

N - Part of Proteins, nucleic acids, chlorophyll
K - Enzyme activator - import. in cell division
Ca - Component of cell walls, & movement of materials within cells
Mg - Component of Chlorophyll, enzyme activator
P - ATP and ADP, nucleic acids, phosolipids
S - Some amino acids and proteins

Fe - Chlorophyll synthesis, respiration
Cu & Mn & Zn - Activator of certain enzymes
B - influences calcium utilization
Mo - Nitrogen fixation, Nitrate reduction

(C/H/O are the primary building blocks of cellulose)

Question 6

What is mineralization?

Answer 6

Once the plant has absorbed then released the nutrients, before it will reabsorb it, the nutrient must be converted to “mineral” forms from their “organic” forms.
(Where Cation Exchange occurs - in the diffusion stage)

Question 7

Why do Bacteria decompose O.M?

Answer 7

To access the Carbon as their Food Source

Question 8

What is the process of organic matter decomposition refereed to as?

Answer 8

Enzymatic Oxidation

Question 9

What influences the rate of Enzymatic Oxidation?

Answer 9

• Type of Organic Matter that is available

- The Sites Climatic Conditions

Question 10

How much does chemical reactions increase with climate?

Answer 10

Every 10 degree increase you get doubling of chemical reactions occurring

Question 11

What are types of O.M and their decomposition rate?

Answer 11

1. Sugars, starches, simple proteins (Rapid Decomposition)
   - Crude Proteins
   - Hemicellulose
   - Cellulose
   - Fats, waxes
2. Lignins and phenolic compounds (Very Slow Decomposition)

Question 12

What do most plants contain (element %)?

Answer 12

~42% Carbon

• 42% Oxygen
• 8% Hydrogen
• 8% Other Nutrients (including Nitrogen)

Question 13

What does Site Climate refer to?

Answer 13

• Drainage
• Temperature
• Moisture
• pH

Question 14

What type of environment do most common and active decomposer organisms prefer?

Answer 14

-Moist
-Well Drained
-Well Aerated
-Neutral to basic pH
(Decomposition most rapid in warm climates)

Question 15

How is Carbon produced?

Answer 15

-Taken out of the atmosphere by plants as CO2 to produce photosynthates and release O2
-Trees produce CO2 in Respiration process
(O.M that they produce is decomposed and CO2 is released back into atmosphere)

Question 16

Young or old Forests absorb more CO2?

Answer 16

Young forests absorb more CO2

Question 17

Can Timber Harvesting accelerate O.M decomposition?

Answer 17

YES! Specially from the forest floor

Question 18

What Carbon, Nitrogen ratio do bacteria require?

Answer 18

`8 parts Carbon for every part Nitrogen (8:1)

Question 19

How much of the Carbon do bacteria use to survive?

Answer 19

1/3, the rest is respired as CO2

In ideal world they need O.M with a C:N of 24:1

Question 20

Biomass and humus in relation with the forest floor

Answer 20

The biomass accumulates on the forest floor. It will keep increasing and can do this significantly but eventually will start to lower. While the Humus increases at a steady even rate.

Question 21

What is the % of nitrogen in our atmosphere?

Answer 21

~78%, mainly as N2 with minor amounts of NO, NO2, N2O and NH3. Some is converted to nitric acid (HNO3) by lightening & washed down into soil by rain

Question 22

What is the % of nitrogen in our atmosphere?

Answer 22

~78%, mainly as N2 (from atmospheric fixation, lightening, fixation by free living bacteria in soil, symbiotic bacteria fixation) with minor amounts of NO, NO2, N2O and NH3. Some is converted to nitric acid (HNO3) by lightening & washed down into soil by rain