3. Soil Water and Air
- Soil water that is also called Soil Solution, is the dilute solution containing small amounts of every soluble compound present in the soils.
- Soil water promotes physical and biological activities of soil, acts as solvent and carrier of nutrients and maintains turgidity of plants.
- Soil water transports nutrients to the root, to the soil surface or subsoil depending on the direction of water flow.
- Soil air is essential for most of the biological reactions in the soil.
- Soil air has about ten times more carbon dioxide than atmospheric air, due to respiration by roots and soil microorganisms.
- Soil air is the pathway for intake of oxygen that is absorbed by soil microorganisms and plant roots and for escape of Carbon dioxide produced by the plants.
- This process called soil aeration is critical for plant growth when water content is high and water replaces soil air.