Scientists say breeding fish can, over the time, reduce salinity

Even as vast tracks of land become infertile or lose productivity globally due to excessive usage of chemicals, scientists believe a natural solution exists. After nearly a decade of research and development, scientists at College of Fisheries say breeding fish can, over the time, undo the effects of modernisation.

Nearly 17 per cent of irrigated land in the country suffers from salinity, wherein pH levels of the soil increases due to excessive use of fertilisers, pesticides and other chemicals, said Shivakumar Magada, Professor at the college.

He was speaking on Wednesday at the inauguration of a 21-day winter school for researchers, academicians and extension workers who were given insights into the techniques and advantages of the project.

Feeler trials

After nearly a decade of ‘feeler trials’, Mr. Magada’s team undertook a five-year research project that started in 2007 in 258 villages of Mandya and Shimoga districts. Aquaculture – the rearing of fish – was tested in its capacity to reduce salinity as well as an alternative source of income for farmers whose yields have been affected by salinity.

“The expenditure is around Rs. 60,000 per hectare to create a pond for a farm that is severely affected. The pond absorbs the salts, while the fish in it neutralises the salinity over time,” he said.

Increased yields

The management of alkalinity had resulted in an increase in yield, Mr. Magada said. His study found that paddy yield increased by more than 0.4 tonnes per hectare, sugarcane by 8 tonnes and coconut by 18 nuts per tree. “Apart from this, the farmer also gets fish production up to the tune of Rs. 17.5 per sq. m., compared to just Rs. 2 per sq. m. obtained from paddy,” he said.

However, like most experiments, failures are not uncommon. “The success rate is over 70 per cent. Failures point to wrong procedures followed – feeding of the fish, quantity of gypsum put in the pond, or farmers putting too many fishlings – and not flaws in the science behind it,” he said.

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