Module 1: Flashcards
Components of Soil
45% mineral material
5% organic matter
25% water
25% air
Physical Properties of Soil
Soil Texture
Soil Structure
Soil Porosity
Organic Components
LFH Horizon
> 30% organic matter
composed of leaves, twigs, and woody material
O Horizon
> 30% organic matter
composed of mosses, rushes, and woody material
A Horizon
<30% organic matter
near soil surface
E Horizon
leached of mineral/organic content
B Horizon
mineral horizon, subsoil, less organic than A
C Horizon
mineral horizon, not very organic
5 Factors of Soil Formation
Parent Material
Climate
Biota
Time
Topography
Soil Texture
relative size of mineral particles
Soil Structure
quality of soil particles binding to form larger particles
Soil Particle Surface Area
as particle size decreases, surface area increases.
Bulk Density
Measure of weight for a given volume of soil and gauges soil porosity/ compaction
Fine textured/organic soils have lower bulk density
Factors Influencing Soil Compaction
Structure
Soil Sortedness
compaction force
soil saturation
Cohesion
Bonding of like substances (water and water)
Adhesion
Bonding of different substances (water and soil)
Macropore
large channels btwn aggregated particles (peds and clods), allowing water and air flow.
Micropore (Capillary Pores)
Small channels within aggregated particles (peds and clods)
Soil Colloids
small soil particles (clay/humus), suspended in water solution
Available Water
water in soil between field capacity and permenent wilting point
Saturation Point
water cannot hold anymore water
Gravitational Water
Water that drains out of macropores (without charge)
Capillary Water
Water held in mircopores (with charge)
Field Capacity
after drained, the maximum water holding porosity
Hygroscopic Water
water held to soil particles at permenent wilting point
Permenent Wilting Point
soil so dry that plants cannot pull any water from it.
Saturated Flow
movement of water when soil is saturated
Unsaturated Flow
movement of water at field capacity or lower
Primary Nutrients from Air:
Carbon, Hydrogen, and Oxygen
Primary Macronutrients
Nitrogen, Phosphorus, and Potassium
Nitrogen Function
part of amino acids and chlorophyll (photosynthesis)
essential for growth
mobile
deficient if leaves yellowing
found in ammonium and nitrate
Phosphorus Function
in every living cell
essential for growth, root development, flowering
deficient if leaves turning red
Potassium Function
required for function of stomata
deficient if leaf margins yellowing
Secondary Macronutrients
Magnesium, Calcium, Sulphur
Micronutrients
Aluminium, Cobalt, Copper, Nickel, Zinc, Manganese, Molybdenum, Iron, Boron, and Chlorine
Mobile Nutrients
Nitrogen, Phosphorus, Potassium, Magnesium, Molybdenum, Chlorine
Immobile Nutrients
Calcium, Sulphur, Iron, Boron, Copper, and Zinc
Raising pH
Use lime.
Lowering pH
Use elemental sulphur.
Carbon Cycle
Natures way of reusing carbon atoms which travel from atmosphere into organisms in the earth back into atmosphere over and over again.
Nitrogen Cycle Steps
- Nitrogen fixation NH3
- Nitrification NH3 to NO4
- Assimilation NO4 to biological tissues
- Ammonification biological tissues to NH3
- Denitrification NH3 to N2
Nitrification
makes nitrogen available to plants by converting ammonia/um to nitrite/ate
Denitrification
nitrate converted to N2 in atosphere
Mineralization
organic matter to plant available nutrients
Immobilization
inorganic nutrients to insoluble organic forms
Nitrogen Fixation
bacteria fix atmosphere N to become available for plants through amino acids
Rhizobia
fix nitrogen, bacteria w mutualistic relationship with legumes
Frankia
bacteria w mutualistic N fixing relationship with examples alder and myrica
CEC
cation exchange capacity
1st Trophic Level
Photosynthesizers
2nd Trophic Level
Decomposers
Mutualists
Pathogens, parasites and root feeders
3rd Trophic Level
Shredders
Predators
Grazers
4th Trophic Level
Higher level predators
5th and higher Trophic Levels
Higher level predators
Parasitism
One organism lives off another organisms (not mutually benficial)
Mutualism
beneficial relationship between individuals of different species.
Mutualistic Bacteria
bacteria feeds on roots as an energy source in exchange for nitrogen for plants
Mychorryzal Fungi
association btwn mycelium of fungus and roots of a seed plant
Plant Root Exudates
chemicals that plant roots secrete into rhizosphere, creating reactions w soil organisms
Exogenous factors
UV
Saturation
Plant Stress
Endogenous factors
Lateral root production
Flowering
Age
Soil Quality
capacity of each soil to function within its natural/managed ecosystems and sustain productivity
Soil Health
condition of the soil and potential to sustain biological functions and environmental quality
Key Threats to Soil
erosion
compaction
land use change
construction
cultivation
Tools to prevent soil loss
compostable blankets
berms
erosion socks
Fresh manure
high salt and nitrogen
weedy
high carbon
Well Rotted Manure
less salt
sometimes less carbon
contains bedding materials
mushroom growth
Mushroom Manure
less salt
high pH 6.5 to 8
some pesticide residue
Sheep Manure
thoroughly digested
no smell
few weeds
high salt
Poultry Manure
harmful to humans
ph 6.5-8
sterile
source calcium/nitrogen
STINKY
Cow/Steer Manure
no weeds
high salt
Pig Manure
needs to be well decomposed
excellent C:N
low salts
Types of Ammending Soil
roto tilling
single/double digging
green manures
texturely
biologically
Types of Composting
static pile
static pile (enclosed)
tumbler
worm bin
bokashi
C:N Ratio
bacteria that can decompose carbon also need nitrogen at a range of concentration (ideally 30:1)
Moisture Content
decomposing organisms need water (ideally 50-60%)
Surface Area
smaller particles decompose quicker
Temperature Compost
bacteria will create heat through respiration and high microbial activity.
