Soils 1 Flashcards
(16 cards)
The importance of soils to the production of food [3]
- Soil resources are a central factor shaping human history and development
- Pasture and crops grow in soil and provide all minerals required by herbivores
- Many health problem of plants and animals arise cos of soil health issues
Components of a soil
Define soil
Soil is the unconsolidated mineral or organic material on the immediate surface of the earth that serves as a natural medium for growth of land plants
Components of a soil
Five major
- Mineral matter (45%)
- Organic matter (1-5%)
- Air (25%)
- Water (25%)
- Soil organisms (billions)
Components of a soil
(Particles in soil) [5]
- Clay -less than 2 microns (<0.002mm)
- Silt -2.20 microns
- Fine sand - 20 microns to 2mm
- Coarse sand
- Organic matter
Basic functions of soils and an understanding of how they support plant growth
(Basic functions of soils) [5]
- Soil serves as a natural medium for the growth of plants
- Regulates and purifies water
- Recycles organic wastes and nutrients
- Provides habitat to soil organisms
- Severs as physical support for buildings and construction and animals
Basic functions of soils and an understanding of how they support plant growth
(how they support plant growth) [9]
- Nutrition
- Water holding
- Stability
- Salinity
- Water logging
- Acidity / Alkalinity
- Aeration
- Control of toxicities
- Thermal insulation
An appreciation of how soils are formed and the factors which impact the rate of formation
(5 Major factors that impact soil formation)
- Parent material
- Climate (precipitation and temperature effects)
- Macro & microorganisms
- Topography (elevation, slope & position)
- Time
How can soils promote or constrain plant production and quality
(Soils can contribute to plant production through) [3]
- Water holding capacity
- Nutrients (N, P, K, Ca, Mg, trace elements etc.)
- Stability
Basic functions of soils and an understanding of how they support plant growth
(how they support plant growth)
-nutrition [3]
- Provision of macro nutrients (N, P & K)
- Provision of micro nutrients (Cu, Zn & Mn)
- From chemical fertilisers or organic sources
Basic functions of soils and an understanding of how they support plant growth
(how they support plant growth)
- Water holding
- The soil needs to rake in water when it rains in order to provide water for a longer period of time
Basic functions of soils and an understanding of how they support plant growth
(how they support plant growth)
- Stability
- Soils requires good mechanical strength to provide crops good grounding to stay upright
Basic functions of soils and an understanding of how they support plant growth
(how they support plant growth)
- Salinity
- Affects around 5% of aus farmland
Basic functions of soils and an understanding of how they support plant growth
(how they support plant growth)
- Water logging [2]
- When soil can no longer take in more water
- Can cause roots to rot
Basic functions of soils and an understanding of how they support plant growth
(how they support plant growth)
- Thermal insulation
- Maintains a stable microclimate
A knowledge of the complexity of managing the attributes of Australian soils
(Aus soils tend to be…) [7]
- Old
- Salty
- Clayey (except in west, more sandy)
- Acidic
- Nutritionally and organically impoverished
- Structurally challenging
- Phosphorus deficient
A knowledge of the complexity of managing the attributes of Australian soils [3]
- Most but not all Aus soils are ancient, strongly weathered and infertile
- Aus rate of soil formation is low by world standards
- Dust storms cause major soil losses
