Ishia was the opposite of Rossak: hot, arid, oppressing to its life forms with heat as Rossak did with cold. Crops which survived did so only because of tremendous amounts of time and energy spent in careful irrigation. The system had to be constantly watched, as a single day's deprivation could kill a field. It was called Albudeite (scarce water) by the Wandering Zensunni.
Sources: Dune Encyclopedia?,