Astamuse Co., Ltd. (headquarters: Chiyoda-ku, Tokyo; President and CEO: Ayumu Nagai) has comprehensively analyzed trends in agricultural nitrogen-cycling technologies using its proprietary innovation database, which covers papers, patents, startups, grants, and other R&D information, and compiled the results into a report. Agricultural nitrogen-cycling technologies aim to control nitrogen losses in farming while addressing greenhouse gas emissions, water pollution, and fertilizer efficiency. Nitrogen is essential for plant growth, but it also has a major environmental impact. The Haber-Bosch process, developed in the early 20th century, enabled mass production of synthetic nitrogen fertilizers and dramatically improved agricultural productivity. However, only about 50% of the nitrogen contained in applied fertilizer is actually absorbed by crops, while the remaining half is released into the environment. This “nitrogen loss” is one of agriculture’s largest unresolved challenges. Part of the lost nitrogen is emitted into the atmosphere as nitrous oxide (N₂O). Agriculture is estimated to account for 60% to 70% of total human-caused N₂O emissions, contributing to global warming and ozone layer depletion. Nitrogen that flows into water systems as nitrate nitrogen (NO₃⁻) also causes eutrophication in lakes and coastal areas and can contaminate drinking water. “Agricultural nitrogen-cycling technology” seeks to solve three issues at the same time: reducing N₂O emissions as a climate measure, preventing nitrate leaching to protect water quality, and maximizing efficiency through precision fertilization. The common root cause behind these issues lies in microbial metabolic processes in soil known as nitrification and denitrification. Nitrification converts fertilizer-derived ammonium ions (NH₄⁺) into nitrate nitrogen (NO₃⁻) via nitrite nitrogen (NO₂⁻). Denitrification reduces NO₃⁻ step by step into nitrogen gas (N₂), sometimes releasing the greenhouse gas N₂O as a byproduct