Salinity

WHAT ARE THE EFFECTS OF EXCESS SALINITY ON PLANTS

Salt is a mineral that is found both in solid and liquid form. The liquid is called brine. Salt contains two elements, chlorine and sodium, and is known chemically as sodium chloride. Mineralogists call salt that is found in mines halite. Salt is essential to health. Body cells must have salt in order to live and work. Salt makes up about 0.9 percent of the blood and body cells. It has been estimated that there are more than 14,000 uses for salt. Most people think of salt chiefly as a seasoning for food. But less than five percent of the salt produced in the world each year is used in this way. Meat packers, chemical companies, hide and leather processors, and food processors, such as manufacturers of dairy products use salt and its by-products. Farmers feed salt to livestock and use it as a preservative for hay in storage. Factories, plants, laundries, and other industrial institutions use salt to soften water and condition it. Salt is also used to hold firm the materials used in building secondary roads. It is also used in heat-treating, smelting, and refining metals. There is a little more than ¼ pound of salt in each gallon (or 30 grams in each liter) of seawater. It has been estimated

Gagnard 2 that if all the oceans dried up, they would leave about 4,419,300 cubic miles of rock salt. That would be enough to cover all the United States except Alaska and Gawaii with a layer of salt more than 1½ miles deep. Salt was first taken from the sea by scooping out shallow holes along the seashore. Waves, breaking along the shore, filled the holes with brine. The sun and wind causes the water in the brine to evaporate, leaving behind the crude salt. This process was known as the solar method. The solar method is still used. But, to speed the process of evaporation, the brine is put in enormous iron pans placed over extremely hot fires. Salt obtained in this manner is very pure. But it has been estimated that a single salt plant should contain at least 5,000 acres of land to make the solar system practical. Salt is found beneath the ground in almost every part of the world. Sometimes the salt lies near the surface or even above it. Rocks of salt that appear above the ground are called salt licks.