Hitachi Zosen, Sumitomo Chemical boast tech to restore tsunami-damaged Japanese farmland


Hitachi Zosen Corp. and Sumitomo Chemical Co. have jointly developed technology to restore farmland damaged by tsunami.

The tsunami spawned by the March 2011 Great East Japan Earthquake ruined farmland by leaving it covered in debris and inundating it with saltwater.

A test of the new technology at a paddy in the hard-hit town of Watari, Miyagi Prefecture, recently proved successful after the field produced rice this fall, the two firms said Wednesday.

The new technology uses GPS to precisely measure the amount of debris and dirt that must be removed before cleansing of the farmland can begin.

Since the dirt and debris were scattered unevenly across the farmland, measuring the amounts was time-consuming. But by using a tractor equipped with GPS equipment, Hitachi Zosen and Sumitomo Chemical were able to measure the ups and downs in the terrain in better detail, cutting the measurement time per hectare by more than three hours to just an hour, they said.

Water and a centrifugal separator are meanwhile used to remove debris, sand and salt from dirt removed from the farmland. The cleaned earth is then returned and fertilizer added.

The cost of the cleanup process is estimated at ¥3,000 per cubic meter, which is about the same as decontaminating a cubic meter of earth tainted by heavy metals.

The actual cost might even drop further since materials removed from the soil can be reused as construction material, the companies said.