Sri Lanka is in the throes of its worst such crisis in more than seven decades. The island of 22 million people has run out of foreign exchange reserves and is unable to pay for critical imports including fuel, food and medicine.

“It is clear the food situation is becoming worse. We request all farmers to step into their fields in the next five to ten days and cultivate paddy,” Agriculture Minister Mahinda Amaraweera told a press conference on Tuesday.

Sri Lanka’s new prime minister Ranil Wickremesinghe has warned of a severe food shortage by August and estimates $600 million will be needed to import fertiliser, which the country is struggling to raise.

Most fertiliser will arrive too late for the next cultivation cycle that usually kicks off in early June, a group of agriculture experts have warned. In the next two seasons, sufficient quantities of fertiliser will not be available to fulfil the nutrient requirements of any of the major crops of rice, tea and maize.

Buddhi Marambe, an agriculture professor at the University of Peradeniya, said some areas will lose more than 50% of the paddy yield even if action is taken.

“Even if we bring fertiliser today, it will be too late to have a good harvest,” he said.

Talks are underway with India to procure 65,000 tonnes of fertiliser and appeals have been made to seven other countries, Amaraweera said. But he did not disclose details of when shipments would arrive.

Last month the central bank announced it would “preemptively” default on some of its external debt as the currency depreciated more than 50% and food inflation hit 46% in April.