  We study the interplay between disorder and a quasi periodic coupling array
in an external magnetic field in a spin-1/2 XXZ chain. A simple real space
decimation argument is used to estimate the magnetization values where plateaux
show up. The latter are in good agreement with exact diagonalization results on
fairly long XX chains. Spontaneous susceptibility properties are also studied,
finding a logarithmic behaviour similar to the homogeneously disordered case.
