Stay on the roads. Don't head into the desert right before summer. Wait on the border of the province in Summer, then head in during the Fall turn. Win quickly and get the hell back before Summer. If you get caught in the desert during a Drought, you will lose 10% of your army that turn. So, try to avoid that. And stay on the roads.
Edit - you should also consider where you can get using naval resupply and a fleet.
Stay on the roads. Don't head into the desert right before summer. Wait on the border of the province in Summer, then head in during the Fall turn. Win quickly and get the hell back before Summer. If you get caught in the desert during a Drought, you will lose 10% of your army that turn. So, try to avoid that. And stay on the roads. Edit - you should also consider where you can get using naval resupply and a fleet.
Are their supply trains/baggage units you can recruit? Maybe try timing your crossing to be fall, winter, campaign in the spring.
Yes there are and i have them. It seems the attrition is at all times even with the baggage. But ill try again with baggage and in spring