Soil salinity is the high salt
concentration in the upper fertile layer of soil; the process of increasing the
salt content is known as salination. Salinization is a process which can result
from:
• High levels of salt in water.
• Landscape features that allow salts to become mobile (movement of water
table).
• Climatic trends that favor accumulation.
• Human activities such as land clearing, beach theft, irrigation, aquaculture
activities and the salting of icy roads.
The consequences of salinity are:
• detrimental effects on plant growth and yield
• damage to infrastructure (roads, bricks, corrosion of pipes and cables)
• reduction of water quality for users, sedimentation problems
• soil erosion ultimately, when crops are too strongly affected by the amounts
of salts.
METHODS OF RECLAMATION.
1) It was thought that introduction of such plants species into salt affected
lands would not only provide green matter (biomass) for various uses but will
also improve the land.
2) It was considered to be possible to evolve salt -tolerant plants, which can
grow on the worst saline lands, even when irrigated with brackish ground water.
3) Such plants could be introduced on barren saline waste lands where no sweet
irrigation water was available and ground water was brackish.
4) The green matter (biomass) produced on these lands could be utilized in
numerous ways such as forage, manure and for making pulp for paper.
5) Using biotechnological methods it could also be converted into other value
added products such as some chemicals, CH4 (biogas) or even alcohol for fuel and
solvent purposes.
6) Cultivation of a crop also results in creating acidic condition in the soil
and green manuring enhances it.
7) It was therefore felt that cultivation of salt tolerant plants and their
green manuring could create the desired acidic conditions to improve the soil
structure and its permeability, which will help leach salt down.
8) Field crops, particularly barley, weed, sorghum, cotton and sugar beet have
been used extensively in bioremediation of saline-sodic sites.
9) By utilizing more water on these crops then is actually needed, salt and
sodium can be need beyond the reach of roots, and the soils can be prepared for
later plantings of more extensive crops (Oster-2001).
10) Bermuda grass, a halophyte, and dry grass have been successfully used as
bioremediation crops in agricultural settings.
There are many more methods which are also useful for cheap reclamation of
saline soils like:
Scraping Removing the salts that have accumulated on the soil surface by
mechanical means has had only a limited success although many farmers have
resorted to this procedure. Although this method might temporarily improve crop
growth, the ultimate disposal of salts still poses a major problem.
Flushing Washing away the surface accumulated salts by flushing water over the
surface is sometimes used to desalinize soils having surface salt crusts.
Because the amount of salts that can be flushed from a soil is rather small,
this method does not have much practical significance.
Leaching This is by far the most effective procedure for removing salts from the
root zone of soils. Leaching is most often accomplished by ponding fresh water
on the soil surface and allowing it to infiltrate. Leaching is effective when
the salty drainage water is discharged through subsurface drains that carry the
leached salts out of the area under reclamation.
Select a crop that fits the conditions in your field.
Know the leaching requirement for your crop.
Keep the right Intervals between irrigation's.
Use appropriate fertilizers types.
Test the soil periodically.
Prepared by:
Zia-Ur-Rahman.
M. Sc. (Hons.) 2nd Semester Environmental Science.