Unit 2 Topic 2 soil. What is soil and why do we care about it? complex mixture: weathered mineral...
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Unit 2 Topic 2 soil
Transcript of Unit 2 Topic 2 soil. What is soil and why do we care about it? complex mixture: weathered mineral...
Unit 2 Topic 2Unit 2 Topic 2
soilsoil
What is soil and why do we care about it?What is soil and why do we care about it?
complex mixture: weathered mineral
materials from rocks partially decomposed
organic molecules Ecosystem services
complex mixture: weathered mineral
materials from rocks partially decomposed
organic molecules Ecosystem services
Soil formationSoil formation Many factors contribute to this LONG process
Parent material, Time, Topography, Climate, Organisms Help determine soil type
Many factors contribute to this LONG process Parent material, Time, Topography, Climate, Organisms
Help determine soil type
Soil Texture Soil Texture Ratio of soil particle size determines some soil
properties Ratio of soil particle size determines some soil
properties
Determining soil typeDetermining soil type
% Increasing Clay
Soil Properties: Porosity Soil Properties: Porosity Affects water infiltration, water holding capacity,
aeration, workability Affects water infiltration, water holding capacity,
aeration, workability
Soil Properties: Chemical Soil Properties: Chemical Cation exchange capacity (aka nutrient holding
capacity) Base saturation
Cation exchange capacity (aka nutrient holding capacity)
Base saturation
SOIL ProfileSOIL Profile
Weak humus-mineral mixture
Mosaicof closelypackedpebbles,boulders
Dry, brown toreddish-brown, with variable accumulationsof clay, calciumcarbonate, andsoluble salts
Desert Soil(hot, dry climate)
Grassland Soil(semiarid climate)
Alkaline,dark,and richin humus
Clay,calciumcompounds
Soil Profiles in Different Biomes
Soil Profiles in Different Biomes
aridisolsmollisols
Acidiclight-coloredhumus
Iron andaluminumcompoundsmixed withclay
Forest litterleaf mold
Humus-mineralmixture
Light, grayish-brown, silt loam
Dark brownfirm clay
Tropical Rain Forest Soil(humid, tropical climate)
Deciduous Forest Soil(humid, mild climate)
Soil Profiles in Different Biomes
Soil Profiles in Different Biomes
oxisols alfisols
Soil Properties: Biotic
Soil Properties: Biotic
surface = algae top few cm of soil =
bacteria & fungi roundworms, segmented
worms, mites, insects farther down: burrowing
animals--gophers, moles, insect larvae, worms
even farther: some plant roots
surface = algae top few cm of soil =
bacteria & fungi roundworms, segmented
worms, mites, insects farther down: burrowing
animals--gophers, moles, insect larvae, worms
even farther: some plant roots
Soil CommunitySoil Community
Soil Community -- Mycorrhizae
Soil Community -- Mycorrhizae
Redwood seedlings with (right) and without (left) mycorrhizae.
Pine seedling showing how mycorrhizal roots from one tree spread to inoculate other tree roots.
mycorrhizal symbiosis - mutualism between plant roots & fungi
Soil degradation and loss
Soil degradation and loss
Soil conservation and improvementSoil conservation and improvement
Organic vs. inorganic fertilizers
Sustainable agriculture practices
Erosion control
Organic vs. inorganic fertilizers
Sustainable agriculture practices
Erosion control
