  We derive a finite set of nonlinear integral equations (NLIE) for the
thermodynamics of the one-dimensional sl(4)-symmetric Uimin-Sutherland model.
Our NLIE can be evaluated numerically for arbitrary finite temperature and
chemical potentials. We recover the NLIE for sl(3) as a limiting case. In
comparison to other recently derived NLIE, the evaluation at low temperature
poses no problem in our formulation. The model shows a rich ground-state phase
diagram. We obtain the critical fields from the T to zero limit of our NLIE. As
an example for the application of the NLIE, we give numerical results for the
SU(4) spin-orbital model. The magnetic susceptibility shows divergences at
critical fields in the low-temperature limit and logarithmic singularities for
zero magnetic field.
