Exam #1-HORT-120 Flashcards
Describe the two factors of nutrient availability
- Availability depends on soil pH
- Availability depends on texture
Briefly explain how nutrient availability is dependent on texture
Finer soils retain more nutrients than coarse soils.
briefly describe Soil Tilth
soil tilth is the suitability of soil to grow plants.
soil texture
soil texture is the size of soil particles
soil structure
soil structure is how the particles fit together
pore space
pore space is the amount of space between the soil particles for water and air to pass through. Increasing organic matter = increasing pore space.
describe soil pH
pH is how basic or acidic the soil is, pH=6 > pH 7
slightly acidic > Neutral
what gives soil its characteristics?
water, porosity, plants and roots, animals, humans and their machinery, fungi.
what are the four soil forming processes?
- additions- putting something in
- subtractions- taking something out
- translocations- within the profile moved from one place to another.
- transformations- changing form (decomp)
what are the five Soil State factors?
the five soil state factors are:
1. Climate
2. Topography
3. Organisms
4. Parent material
5. Time
How does climate affect soils?
Wind, precipitation, sun exposure, freeze/thaw, and temperature changes (especially heat), can alter chemical reactions in soil and the rate of said reactions and decomposition.
What is Topography?
where something is located in terms of mountains, valleys, slope and elevation etc.
what are soil horizons?
layers of soil- O, A, B, C, R
What is “soil orders”
soil orders are the distinct horizon combinations, there are 12.
What is Michigan’s state soil?
Kalkaska sand- a spodsoi. the sand layers range from yellow to red to black.
What does Tillage do to soil structure? (positive)
- promotes aggregation
- allows root penetration (aeration)
- compaction to allow imbibing
-incorporates organic matter
What does Tillage do to soil? (negative)
- destroys aggregation (releasing carbon)
-reduces airspace (increase compaction)
-speed up loss of organic matter
What is soil made of?
soil is made of minerals, organic matter, water, air and gases, and organisms.
What is a mineral?
A Mineral is a substance found in soil that is inorganic, but naturally formed.
Primary minerals
primary minerals are rocks formed at HIGH TEMPS: from igneous and metamorphic rock.
Secondary minerals
Secondary minerals are rocks formed at LOW TEMPS: from sedimentary rocks/weathering
what are the three mineral groups?
- Aluminosilicates
- Oxides (magnesium, iron)
- Minerals made from organic matter (mostly plant material).
All ( ) is organic matter, but not all ( ) is humus.
Humus, organic matter.
briefly describe Humus Organic Matter
Humus organic matter is brown/black material that results from decomposition
what effects the rate of decomposition?
pH, Temperature, Climate, and the composition of organic matter.
What are the two types of Humus?
- Active
- Passive
Describe Active Humus
active humus adds nutrients, not structure, so it is still decomposing.
Describe Passive Humus
passive humus adds structure, not nutrients so it is done decomposing.