Farmers in the Murray-Darling Basin increased their land under irrigation and water use during the last financial year even as the region endured its second-driest period since 1943, data from the Australian Bureau of Statistics show.

While cotton had a bumper year with the value of its 2017-18 national crop jumping 49 per cent to $2.5 billion, separate ABS figures show, the industry estimates irrigation shrank by half during 2018-19 and will decrease as much again in 2019-20.

Cotton farms in February near Warren. Credit:Jeremy Buckingham

The Murray-Darling Basin accounted for about 70 per cent of agricultural water use nationally in 2017-18. About 1.5 million hectares in the region were irrigated, up 8 per cent on the year earlier. Some 6.8 trillion litres were used on farms, a rise of 7 per cent, the ABS said.

Cotton farms in the basin alone used 2.505 trillion litres of water on 320,000 hectares of land, both up about 4 per cent from 2016-17.