Harmful effects of water logging and salinity
Harmful effects of waterlogging and salinity are caused by unthoughtful planning of irrigation system.
With respect to water logging and salinity, there are following harmful effects:
- Waterlogged soil provides excellent breeding grounds for misquitoes, and cause malaria.
- It causes loss in crop yield.
- When waterlogged soil are fully saturated, plant roots can not absorb water. Therefore, they are deprived of aeration. Due to absence of aeration, anaerobic conditions exist killing the aerobic bacteria present in the root-zone of the plant. This aerobic bacteria helps to make food for the plant. This aerobic bacteria transform chemical compounds into nitrogen and phosphorus and provides food to the plant. Due to waterlogging, killing of this bacteria occured and ultimately causes the death of the plant.
- In rainfall or irrigation, water after saturating the root-zone travels downward washing down excess salts. When the unsaturated conditions begin, plant start taking up water. In waterlogged soil, water moves upwards due to capillary. It bring up salts more and more in the root-zone. Thus making soil solution excessively saline. The plant then faces hindrences in taking up moisture. This results in permanent wilting of the plant.
- Where land is totally waterlogged, salinity causes destruction of vegetation and crops. Waterlogging causes depostion of salts in the root zone. If the salts are alkaline, then soil pH increases. If the soil pH increases to 8.5, it effects the plant and if increases to 11.0 then plant becomes infertile. If the salts are acidic, then its lower the pH. For acidic salts with pH low than 4, plants cannot absorb nutrients and die.
- Destruction of roads occured due to reduced bearing capacity of waterlogged soil.
- Rise of water through capillary in the buildings, causes dampness and therefore causes diseases. This also causes peeling off plasters and appearance of salt patched on the walls of the buildings.
- Certain weeds grow very fast in the waterlogged area and normal crops cannot compete with them. Thus suppressing the useful crops to grow.
- Due to reduced bearing capacity, agricultural machinery cannot operate well in the fields.
- Saline soil being unfit for agriculture is used for making bricks. The salts from these bricks appear on the surface whenever they get dry.