<p>We designed a study to examine the long-term spatial and temporal patterns of mass loss, changes in nitrogen content and chemical composition during decomposition of roots in a desert watershed. Because nitrogen availability has been hypothesized to affect decomposition rates of buried litter in deserts, we studied decomposition of roots along a transect on a desert watershed that had been fertilized with ammonium nitrate and compared these results with the decomposition of roots along a transect that had not been fertilized.</p>