Test undergraduate understanding of soil nitrogen cycling: key microbial pathways (fixation, mineralization/ammonification, nitrification, denitrification, immobilization), primary reservoirs (atmosphere, soil organic matter, NH4+, NO3−, microbial biomass, plants), major fluxes and losses (leaching, volatilization, N2O emissions), and how common agricultural practices (synthetic and organic fertilizers, tillage, crop rotation/cover crops, irrigation, manure, liming) alter rates, pool sizes, and environmental outcomes; students should explain processes, interactions, and interpret scenario-based management effects.