Glacierwood Siege’s Sultai ability doesn’t allow you to activate abilities (such as cycling) of land cards in your graveyard.

Glacierwood Siege’s Sultai ability doesn’t change the times when you can play those land cards. You can still play only one land per turn, and only during your main phase when you have priority and the stack is empty.

If you somehow control Glacierwood Siege and no choice was made for it (perhaps because another permanent on the battlefield became a copy of it), it has neither of the two abilities.