ASSESSMENT OF WATER QUALITY FOR IRRIGATION
The productivity of a soil irrigated with low quality water may decline because of the following problems:
- Increased salinity;
- Low soil permeability - either as a result of sodium accumulation in the exchange phase and soil swelling into the conducting pores, or deposition of low solubility salt such as CaCO3 and CaSo4 in the soil pores, or the formation of a clay pan in soil profile;
- Deterioration of the soil structure;
- Contamination of the soil with potentially toxic substances such as trace elements, biocides, etc.
Historically, 2 main factors have been considered in evaluating the suitability of water for irrigation and in water management, the properties of the water (salt concentration and composition) and the salt tolerance of crops.
Recently it has been realized that the interaction between the physicho chemical properties of the soil and the irrigation water is also a very important parameter in evaluating the suitability of water for irrigation and in water management.