Biological Properties of soil Flashcards
Soil Biomass
The total mass of living organisms in the soil
Soil Biomass
The total mass of living organisms in the soil
Humus
The plant and animal material which has been decomposed.
Humification
The process by which soil organic matter is converted to humus.
Microbiome
A community of microorganisms (e.g. bacteria and fungi) that inhabit a particular environment.
Symbiotic relationship
Where different species of living organisms live in a close relationship and both
organisms benefits.
Rhizosphere
The rhizosphere is the area around the roots of a plant occupied by unique microorganisms influenced by the chemicals released from plant roots.
Endorhizosphere
Area of the cortex and endodermis of root where microorganisms can occupy spaces between cells and makes use of nutrients by roots
Rhizoplane
The external surface of the roots and adhering soil particles.
Ectorhizosphere
The area of the rhizosphere which extends from the rhizosphere to the bulk soil.
Calculating soil organic carbon
(SOC)
% SOC = mass of soil organic matter (SOM) X 0.58
Carbon Cycle (KNOW DIAGRAM)
Is the way carbon is used, reused and recycled in nature by living organisms converting it from carbon dioxide (photosynthesis) to carbohydrate and in the soil to carbonate ions.
Nitrogen Cycle (KNOW DIAGRAM)
Is the way nitrogen is recycled in nature, being converted from atmospheric nitrogen to ammonia and then to nitrates and nitrites before being converted back into nitrogen gas.
Nitrogen fixation
Is the process by which nitrogen gas is converted into nitrates which can be used by plants.
Nitrification
Conversion of ammonia or ammonium compounds into nitrite or nitrate
Denitrification
Nitrates are converted to nitrogen gas and nitrogen oxide
Macro-organisms
Organisms that can be seen by the naked eye. E.g. earthworms
Microbiome
A community of microorganism (Bacteria & Fungi) that inhabit a particular environment.
Mineralization
Process in which carbon (C) and nutrients are transformed to CO2 and plant-available forms of nitrogen (N), Phosphorus (P), and sulphur (S).
Bacteria
- Single celled organisms,
- Bacteria in the soil are responsible for fixing nutrients into forms that can be absorbed by plants (e.g. nitrogen and phosphorus)
- Bacteria in the soils also act as decomposers, breaking down organic matter in humus. This recycles nutrients so they can be absorbed by plants.
Fungi
- Fungi in soil act as decomposers, breaking down organic material in humus. This recycles nutrient so they can be absorbed by plants.
- Range from microscopic in size to large mushrooms.
- Responsible for humification of soil organic matter.
- Some fungi form symbiotic relationship with other living organisms.
- Some fungi are parasitic and can damage crops.
parasite
A parasite is an organism that lives on another organism (called a host) causing it harm
EG.) Liver-fluke on sheep
what happens in the rhizosphere
-As plants grow, they release amino acids and sugars into the soil.
- These compounds provide a nutrient supply for the soil micro-organisms.
- This results in a high concentration of microbial activity in the rhizosphere.
- The bacteria and fungi in the rhizosphere create a nutrient rich zone around the roots.
- Symbiotic relationship
- The fungus benefits from the energy produced by the plant, and the plant benefits from mineral nutrients and water supplied by the fungus
Mycorrhiza fungi
- Found in symbiotic relationship within the roots of plants.
- They increase the surface area of the roots for absorption and help dissolve nutrients so they can be absorbed by plants.
- They also enhance the water-holding capacity of the soil and helps bind soil particles together.
-The presence of these fungi increase productivity of crops by improving nutrient uptake.