Soil Trial Test Flashcards
What is soil texture?
It is the relative proportions of sand, silt and clay in soil
Why is clay important or soil?
It provides a reservoir for water and plant nutrients
What is a field texture assessment?
It’s based on the ‘feel’ of a soil and it’s response to certain simple tests.
Why are loamy soils generally ideal under a wide range of conditions?
The mixed particle sizes allows a good balance of soil air and water.
Why does a loamy soil usually hold more water than a sandy soil?
Because of its clay content
What do sandy soils tend to exhibit?
Good drainage
Will the addition of decomposed organic matter affect soils texture?
No
What does the soil texture assessment test determine?
Clay content, drainage, water holding capacity
What soil texture won’t be affected my heavy pedestrian traffic?
Coarse textured soils
Give an example of a group of soil textures that are most likely to have an apedal structure.
Loamy sands, sands, sandy loams
What is the most desirable ped type in an aggregated topsoil?
Granular or crumb
A fine textured soil that has good tilth has…
A granular structure, good aeration, good drainage and good water holding abilities.
What is soil structure?
The size, shape and arrangement of soil peds and the pore spaces between them.
Fine textures soils that have a high concentration of Na (sodium) ions are…
Likely to disperse easily.
What are the a and b horizons collectively called?
Solum
In a soil profile, what material does the c1 horizon contain?
Weathered parent material.
In a soil profile, what could assist in good drainage?
The absence of a finer textured layer of soil on top of a coarser layer.
What type of water is most available to plants at field capacity?
Capillary water
In a soil profile what does the colour rich brown indicate?
High in O.M
In a soil profile what does the colour red indicate?
Good aeration and drainage
In a soil profile what does the colour grey/orange mottling indicate?
Temporary water logging
In a soil profile what does the colour light grey indicate?
Saturated
What is a ‘Capillary Fringe’?
It’s subsurface layer in which groundwater seeps up from a water table
Can capillary water be removed by ag pipe?
No
What can be the result of a finer textured layer of soil on top of a coarser layer?
A capillary fringe
How can a capillary fringe be beneficial?
If deep enough below the surface if can aid the hydration of plants.
What is the term used to describe the movement, in water, of nutrients and fine particles downwards into the soil?
Leeching
What is the term used to describe the % of water remaining in the root zone after the soil has been saturated and free drainage has ceased?
Field capacity
What is the term used to describe the type of water remaining in soil after it has dried out?
Hydroscopic
The type of water which drains from a soil soon after rain or irrigation.
Gravitational
What is the term used when all pore spaces in a growing media are occupied by water?
Saturation
Soil water is usually held in the __________ pores.
Micro
In a aggregated stability test, what is meant by a stable ped?
When a ped stays together in distilled water and nothing happens. (ideal soil)
In a aggregated stability test, what is slaking and how can you treat it?
When a ped falls apart and water is clear. Treat with O.M
In a aggregated stability test, what is a dispersive soil and how can you treat it?
When a ped falls apart and clouds the water. Treat with Gypsum (Calcium Sulphate)
What drainage problem occurs when a layer of fine textured soil sits on top of a courser layer?
Perched water table
What is the term used when water fails to infiltrate a sandy soil?
Hydrophobic sand
What does a wetting agent do?
It is used to improve a soils ability to accept water.
What horizon do most plants grow?
A horizon
Is capillary water available to plants?
Yes
What is tilth?
The physical condition of a soil.
