The area of soil within a few millimetres of the roots, where the biological, chemical and physical properties and hydrology of the soil are influenced by the root.
The narrow zone of soil near plant roots, where concentrated microbial activity and chemical reactions are significantly influenced by the roots.
Roots exudates provide carbon and nutrients to rhizosphere organisms. Exudates include sugars, amino acids, organic acids, vitamins and larger molecules. The composition and volume of root exudate compounds released are influenced by several factors, including plant species and age, climatic conditions, and the biological, chemical, physical, and hydrological properties of the surrounding soil.
On wetting, porous soil aggregates rapidly absorb water and soil may swell, becoming soft and trapping air internally. With further wetting, weak aggregates collapse and break into smaller particles. This process is known as slaking. It is essentially a collapse of the soil structure on wetting.
Slaking is due to low soil organic matter and is often associated with intense rainfall hitting dry, bare soil and occurs within minutes. It can lead to the blocking of soil pores normally associated with gas exchange and water movement. In naturally hard-setting soils that are unable to reform aggregates, a crust will form when the soil surface dries.
A sodic soil has an exchangeable sodium percentage (ESP) of greater than 6% of the cation exchange capacity.
Refers to the total mass of soil microorganisms—primarily bacteria, archaea and fungi, excluding plant roots and larger soil fauna and is typically measured in terms of the amount of carbon, nitrogen, or phosphorus content in their cells.
Relating to the earth.
An accumulation of cold temperatures is necessary for plants to progress from a vegetative stage to a reproductive stage.
An accumulation of cold temperatures is required before plants progress from a vegetative to a reproductive development stage.
Water holding capacity (WHC) is defined as the amount of water that is retained by soil against gravity.