Ammonium-15N nitrate is widely used as a labeled nitrogen source in agricultural research to study nitrogen uptake, assimilation, and metabolism in plants. Its isotopic labeling allows scientists to trace the movement and transformation of nitrogen in soil-plant systems, aiding in the development of efficient fertilization strategies and reducing environmental impact. It is also employed in environmental studies to investigate nitrogen cycling in ecosystems, including processes like nitrification and denitrification. In biochemistry, it serves as a tracer to study nitrogen-containing compounds in metabolic pathways. Additionally, it is utilized in medical research for isotopic labeling in protein and nucleic acid studies.