The concentration of soluble salt in irrigation water is generally expressed in parts per million (ppm) or milligrams per liter (mg/l).
The suitability of irrigation water is heavily influenced by its salt concentration. High levels of soluble salts can negatively impact plant growth and soil health. Here's a breakdown of critical salt concentrations:
- Acceptable Levels: Salt concentrations below 700 ppm are generally considered safe for most plants.
- Harmful Levels: Concentrations exceeding 700 ppm can be harmful to salt-sensitive plants.
- Injurious Levels: Concentrations above 2000 ppm are typically injurious to nearly all crops.
It's important to note that the tolerance levels of plants to salinity vary greatly. Some plants are more salt-tolerant than others.
Relationship between Salt Concentration and Electrical Conductivity:
Salt concentration and electrical conductivity (EC) are directly proportional. Electrical conductivity is a measure of the water's ability to conduct an electrical current, which increases as the salt concentration increases. EC is often used as a proxy for measuring the total dissolved salts (TDS) in water.
Factors Affecting Salt Concentration:
- Source of water: Groundwater, surface water, and treated wastewater can have varying salt concentrations.
- Rainfall: Rainfall can dilute salt concentrations in surface water.
- Agricultural practices: Irrigation practices can contribute to salt buildup in soils.
- Geology: The geology of an area can influence the salt content of water sources.
In conclusion, the concentration of soluble salt in irrigation water, measured in ppm or mg/l, is a critical indicator of water quality. Keeping salt concentrations within acceptable levels is essential for maintaining plant health and soil productivity.
