Changes in temperature, drought frequency, and atmospheric nitrogen (N) deposition are altering N cycling in dryland ecosystems, which make up approximately one third of the Earth’s land surface. Because biological productivity in these systems is co-limited by water and nutrient availability, N export can occur when availability does not coincide with moisture conditions necessary to build up and sustain biological N-demand. This export can be detrimental to both air and water quality. For example, microbial processing of N can produce both nitric oxide and nitrate, which contribute to tropospheric ozone and downstream eutrophication, respectively. While much research has focused on identifying the physiological processes that control dryland N cycling, it is less clear how these processes interact to drive N export at landscape scales. To address this, it is crucial to understand how plant and microbial processes interact to control N transformations over space and time. For instance, plants help regulate how much N is available for microbial N metabolism, and microbial N fluxes feed back to influence plant dynamics across landscapes. Because plant and microbial N transformation pathways can have distinct responses to environmental conditions—such as soil moisture and temperature—they may also have differing responses to global changes, including increased drought, warmer temperatures, elevated N deposition, and increased fire frequency. Thus, the goals of this session are to: 1) highlight the current understanding of physiological and landscape controls over dryland N cycling, 2) assess how these different spatial scales can be integrated into ecosystem models of dryland N cycling, and 3) identify how these cross-scale linkages respond to environmental change.