Soils Flashcards
What does aeration by ploughing and drainage do?
Ploughing and drainage make soils more aerobic.
This increases the rates of nitrogen fixation, nitrification, and the decomposition of dead organic matter.
Farmers increase soil nutrient levels by
Adding fertilisers and organic matter
what does irrigation do?
Increases the fertility of soil because water is a limiting factor on growth
What is Soil Compaction?
The use of heavy machinery or high livestock densities, especially when the soil is wet, causes soil to become compacted.
This reduces aeration and makes waterlogging more likely.
What does Ph control do?
Controlling soil pH helps to ensure nutrients are soluble but not too easily leached.
What is Soil Erosion?
Soil particles removed by wind or water.
what can Overgrazing lead to?
If the livestock density is too high then the vegetation will be eaten faster than it can grow, increasing the exposure of the soil and the risk of erosion.
Disturbance and root damage by hooves increases the risk of erosion.
Components of soil
Minerals, organic matter, water, air
Water in soil is important because
Important for dissolved nutrients and is a heat sink
Soluble materials in soil
macronutrients such as nitrogen, phosphorus, and potassium, present in ionic form mainly as nitrates, phosphates, and potassium ions
Dead organic matter is important to soil because
bacteria return nutrients to the environment by breaking it down
What is soil biota?
organisms that spend all or a portion of their lifecycle within the soil or on its immediate surface
pH of fertile soils
fertile soils is usually in the range 5.5 to 7.0 which is the range of tolerance for most plants and other soil biota.
What are Nitrogen fixing bacteria?
bacteria that convert atmospheric nitrogen into ammonia
What is Nitrifying bacteria?
Bacteria that change dissolved ammonia into nitrite compounds or nitrites into nitrate compounds.
What is Mycorrhizal fungi?
fungi that surround plant roots and help plants obtain water and minerals
What do detritivores/decomposers do?
recycle nutrients within the ecosystem by breaking down non-living organic matter
What is the soil triangle used for?
used to determine textural classes of soil from the percentages of sand, silt, and clay in the soil
What is soil texture?
Relative amounts of the different types and sizes of mineral particles in a sample of soil.
