Introduction To Soil Flashcards
How do soil properties influence production?
Ease clearing of land
Provide water and nutrients for plant growth
Drainage systems
Trellising and dams for water storage
How can soils be improved?
Fertiliser application Drainage Irrigation Crop rotation Grazing management
What can poor soil management lead to?
Erosion results in loss of fertile top soil
Poorly timed cultivation causing compaction
Excessive fertiliser leads to salinity or acidity
Contamination of soil with toxic heavy metals
How does soil influence plant growth?
a. Physical medium for root growth
b. Supply water
c. Supply oxygen
d. Provide a suitable chemical environment
e. Provide a suitable biological environment
What are the characteristics of soil?
Physical medium for root growth Supply water Supply Oxygen Chemical environment Suitable biological environment
What is soil the physical medium for root growth?
In the very simplest sense, soil provides support of the plant by allowing root development. Where root support is limited, for example, where the depth of root development is restricted by bed-rock or a compact pan; trees can be easily blown over by high winds.
How does soil supply water?
The ability of soils to store water is generally not a problem in areas where rainfall is high and regular and exceeds evaporative losses. However, this rarely occurs in the Australian environment so that the ability of soils to permit water entry and then store water for subsequent root uptake is normally of major importance.
Impeded drainage results in waterlogging.
How does oil supply oxygen?
Plant roots require oxygen for normal respiration so soils must be sufficiently permeable to allow the air to diffuse rapidly through the soil.
How do soils provide a suitable chemical environment?
Plants obtain certain elements from soils that are necessary for plant growth, for example, nitrogen (N), phosphorus (P), zinc (Zn) etc. Problems of toxicity can occur if the concentration of nutrients is too high.
How does soil influence animal production?
a. Quantity of pasture
b. Quality of pasture
c. Disease / animal health
How does soil affect the quantity of pasture?
The fertility of soils influences the yield of dry matter available for livestock. The dry matter provides the energy for animal growth.
How does soil affect quality of pasture?
Not only do animals require pasture for energy, but pasture must be of good quality to maintain the growth and health of grazing stock. A major problem in pasture is the protein content. As soils are commonly N deficient and as N is a basic constituent of protein, low soil N levels cause the protein content of the herbage to be low.
How does soil affect disease/ animal health?
Waterlogged or poorly drained soils are favourable for survival of the parasite liver fluke and the bacteria that cause tetanus.
On sandy soils, teeth wear in sheep is more rapid resulting in premature ageing.
Why and how does soil vary in composition?
The properties of a soil are influenced by the way it was formed. Soil formation, itself, is affected by many factors. In particular, the soils are different depending on the local topographic position in which they are located.
It is usual to find each landscape unit characterised by one or several major soil types and associated minor types.
