Sodic soil severely hinders plant growth by negatively impacting the soil's physical and nutritional characteristics.
Understanding Sodic Soil
For the purpose of definition, sodic soils are those which have an exchangeable sodium percentage (ESP) of more than 15. This excess exchangeable sodium is the primary issue causing harm to plant life in these environments.
Impact on Soil Properties and Plant Growth
The presence of excess exchangeable sodium in sodic soils has a profound adverse effect on the soil's fundamental properties:
- Physical Properties: High sodium causes soil particles (especially clay) to disperse. This breakdown of soil structure leads to poor aeration, reduced water infiltration, and impaired drainage. The soil can become hard and compacted when dry, making root penetration difficult and limiting oxygen availability for roots.
- Nutritional Properties: Sodic conditions can negatively affect the availability and uptake of essential plant nutrients. High concentrations of sodium can also be directly toxic to sensitive plant species or interfere with the plant's ability to absorb necessary elements like calcium and potassium.
These negative changes to the physical and nutritional properties of the soil have a direct consequence: a reduction in crop growth. As the reference states, this reduction can be significantly or entirely, severely limiting crop yield or preventing plants from growing altogether.
In essence, sodic soil creates a challenging environment where plants struggle to access water, air, and nutrients, while potentially facing direct toxicity from excess sodium, leading to stunted or absent growth.
