Carbon neutral? No change in mineral soil carbon stock under oil palm plantations derived from forest or non-forest in Indonesia

•Life cycle changes in soil Cstock of oil palm plantations affect national C balance.•No net C emission from soil was detectable across 20 plantations and 155 plots.•Loss and gain of Corg and changes in bulk density balanced out over management zones.•Current retention of palm residues in the field can maintain mineral soil Cstock.•Mineral soil Cstock neither increases nor decreases due to current oil palm cultivation.