Physical Characteristicss Flashcards
What is soil Structure?
The size, shape and arrangement of the soil particles and how they are distributed in the soil
How is Structure measured?
Observing the soil and comparing the soil key
How does structure affect plant production?
Well structured soils have pores, channels or spaces between the aggregates. If soil becomes compacted it destroys these spaces
How can Structure be modified?
Reducing levels of cultivation to conserve structurer and reduce erosion
What is soil Texture?
Is a property that measures the percentage of sand, silt and clay in the soil
How is texture measured?
Squeeze wet soil into a ribbon; sandy soil breaks fast, clay soil stretches long
How does Texture affect plant production?
Ease of cultivation and Fertility levels
How can texture be modified?
The best way to break down clay is to apply gypsum
What is porosity?
Is the size, shape and arrangement of soil particles that determine the amount of air space within the soil
How is Porosity measured?
Pouring water on soil in a vile and measuring how much it takes to reach the top
How does porosity affect plant production?
Soils with good porosity Require fewer cultivations and allow easy root penetration and water and air flow whereas poor porosity affects gas exchange and therefore plant growth and yield
How can porosity be modified?
Avoid overgrazing and carrying capacity
What is Bulk Density?
Is the weight of a unit of volume of soil. It gives an indication of the “strength” of the soil
What is Bulk Density measured?
Bulk density is measured by taking a cylindrical soil core of a known volume, drying it in an oven, and then weighing it.
Bulk density =?
Dry weight of sample DIVIDED BY the volume of the soil core
How does Bulk Density affect plant production?
A higher bulk density means the soil is more highly compacted it may cause restrictions to root growth and poor movement of air and water through the soil
How can Bulk Density be modified?
Reduced cultivations and Grazing management
