A soil may be rich in salts because the parent rock from which it was formed contains salts. Sea water is anothersource of salts in low-lying areas along the coast. A very common source of salts in irrigated soils is the irrigationwater itself. Most irrigation waters contain some salts.
After irrigation, the water added to the soil is used by the crop or evaporates directly from the moist soil. The salt,however, is left behind in the soil. If not removed, it accumulates in the soil; this process is called salinization.
Soil salinity and alkalinity has many adverse effect:
- Soil fertility is reduced which results in crop failure. Cultivation is not possible on saline soils unless theyare flushed out with large quantities of irrigation water to leach out the salts.
- Choice of crops becomes limited because some crops are sensitive to salinity. Only high salt tolerantcrops such as cotton, barley etc. and medium tolerant crops like wheat, rice, linseed, pulses, millets etc.can be grown.
- Quality of fodder crops is also reduced.
- Salinity and alkalinity creates difficulties in building and road construction.
- These cause floods due to reduced infiltration, leading to crop damage in the adjoining areas.