SECTION G Flashcards
five factors of soil formation
parent material
climate
biota
topography
time
(parents can be tactful teachers)
colluvial deposits
formed from weathered material transported by gravity
alluvial materials
sediments transported by rivers and streams
glacial deposits
form of glacial till are the underlying material of most of the forests soil
eolian parent material
loess (fine wind deposited silt) and cover sands
marine deposits
fine silts and clays deposited on ocean floor
lacustrine deposits
materials that are deposited in lakes
ABC horizons
a- rotting plants/finely decomposed rock
b- decomposed rock/some rotting plants at top of layer
c- slightly altered parent material
direct consequences of soil compaction
degraded soil structure
impaired root growth
slower water infiltration
poor aeration
reduced drainage
reduced macrofauna
indirect consequences of soil compaction
nutrient deficiencies
drought
susceptibility to root rot
increased soil erosion
how to promote beneficial soil organisms
adding compost
adding manure
managing plant waste residues
not working soil when wet
inter-row seeding
cover cropping
primary consumers
actinomycetes, fungi, and bacteria
secondary consumers
herbivores
i.e. flies/larvae, dipterans, springtails, mites, earthworms, snails/slugs, sowbugs, millipedes
tertiary consumers
carnivores
i.e. ants, groundbeetles, centipedes, predatory mites, pseudo-scorpians
3 step nutrient absorbtion from roots
- nutrient ions transported thru soil to root surface
- root surface removes and absorbs available ions
- root distributes absorbed nutrients to the rest of plant
nitrogen soil conditions
low organic matter = low N
course texture = easily leeched of N
frequently flooded soils = denitrification
phosphorus soil conditions
P immobilized when high ph/low ph
coarse texture = inherently low P, poor P retention
low temp decreases P availability
potassium soil conditions
coarse texture = leeched of K
organic soils are low in K
excess Ca, Mg, Na will decrease K uptake
sulphur soil conditions
coarse texture = leeched of S
low organic matter = low S
s persists in seawater soils
calcium soil conditions
Ca easily leeched in acidic/coarse soils
excess K and Na decrease Ca uptake
magnesium soil conditions
Mg is often deficient in organic soils
low pH and excess K, Ca, Na decrease Mg uptake
iron soil conditions
most available in acidic soil
excess nutrients depress Fe
nitrates in soil can reduce Fe uptake
calcium rich soil is Fe deficient
manganese soil conditions
Mn deficient in alkaline soils
high other nutrients can lower Mn uptake
Mn can be immobilized in organic soil
copper soil conditions
CU deficienccy common in alkaline soils
applications of N can supress Cu uptake
