Ethiopia said Thursday it was closing secondary schools for a week to allow students help in harvesting crop fields left behind by civilians who enlisted in the military.
The order was given by Addis Ababa's education ministry, the Xinhua news agency reported citing local broadcaster Fana.
Thousands of people have answered Prime Minister Abiy Ahmed's call to join the country's armed forces to defeat a rebel uprising in the north and centre of the country.
Last week, Abiy himself joined the frontline to oversee operations against the rebels.
The army has since retaken several key towns and cities across Amhara and Afar regions, including Lalibela, the site of UN World Heritage site which had been occupied by rebels for months.
Abiy has called on rebel soldiers to surrender.
September to February are a major crop harvesting season in Ethiopia. But in the Tigray, Afar and Amhara regions, fighting has disrupted farming prompting warnings of serious food shortages.