Toronto: Every day for more than 20 years, an average of 2,000 hectares of irrigated land in arid and semi-arid areas across 75 countries, including in India, has been degraded by salt, a research has found.
Today, an area the size of France - about 62 million hectares or 20 percent of the world's irrigated lands, up from 45 million hectares in the early 1990s - is affected, the findings showed.
"Efforts to restore those lands to full productivity are essential as world population and food needs grow, especially in the developing world," said Zafar Adeel, director of UN University's Canada-based Institute for Water, Environment and Health.
India's Indo-Gangetic Basin is among the well-known salt-degraded land areas in the world.
Salt-degradation occurs in arid and semi-arid regions where rainfall is too low to maintain regular percolation of rainwater through the soil and where irrigation is practiced without a natural or artificial drainage system.
Irrigation practices without drainage management trigger the accumulation of salts in the root zone, affecting several soil properties and reducing productivity.
The inflation-adjusted cost of salt-induced land degradation in 2013 was estimated at $441 (Rs.27,035.51) per hectare, yielding an estimated global economic losses at $27.3 billion (Rs.167,363 crore) per year.
In India's Indo-Gangetic Basin, crop yield losses for wheat, rice, sugarcane and cotton grown on salt-affected lands could be 40 percent, 45 percent, 48 percent, and 63 percent, respectively.
Employment losses could be 50-80 man-days per hectare, with an estimated 20-40 percent increase in human health problems and 15-50 percent increase in animal health problems.
"It is important to note that the above numbers of global cost of salt-induced land degradation refer to economic losses based on crop yield losses only," the researchers said.
Pertinent policies, well-designed salinity management plans, supportive institutions, skilled human resources, provision of facilities and infrastructure for disposal of salts are crucial in combating salt-induced land degradation, they added.
The study appeared in the journal Natural Resources Forum.