  We use the density matrix renormalization group to study the quantum
transitions that occur in the half-filled one-dimensional fermionic Hubbard
model with onsite potential disorder. We find a transition from the gapped Mott
phase with algebraic spin correlations to a gapless spin-disordered phase
beyond a critical strength of the disorder $\Delta_c \approx U/2$. Both the
transitions in the charge and spin sectors are shown to be coincident. We also
establish the finite-size corrections to the charge gap and the spin-spin
correlation length in the presence of disorder and using a finite-size-scaling
analysis we obtain the zero temperature phase diagram of the various quantum
phase transitions that occur in the disorder-interaction plane.
