This study hypothesized that changing densities of soil microarthropods and nematodes would result in changes in nitrogen availability. In order to test this hypothesis, Erioneuron pulchellum rhizosphere soil samples were taken monthly from control plots, plots irrigated with 6 mm/wk., plots soaked with chlordane (to remove microarthropods), and plots treated with chlordane that were irrigated with 6 mm/wk. These samples were analyzed for available inorganic nitrogen (NO and NH ), gravimetric soil moisture, and nematode and microarthropod densities. This dataset contains the environmental data and nematode population results. Nematodes increased density in response to elimination of microarthropods only during the unusual wet winter-spring 1986-87, when soil water potential was above MPa most of the time. Also, there were no significant differences in nitrogen mineralization potentials of soils from the various treatments. These data indicate that soil microarthropods are not essential for nitrogen mineralization or other aspects of the nitrogen cycle in the rhizosphere of fluff grass.