Database of nitrogen fertilizer reduction experiments conducted in Japan

This database is compiled using a literature survey using Google Scholar and AgriKnowledge to gather data on synthetic nitrogen fertilizer (SNF) reduction experiments in Japan. The search included terms like “synthetic nitrogen fertilizers,” “Japan,” and “crop yield,” and was refined with Boolean operators. The gathered information covered various crops, cultivation periods, SNF input, and organic material N efficiency.Four approaches to nitrogen reduction were identified. The "Reduction" approach involves simple SNF reduction without changing fertilizer type, including zero N treatments. The "Functional fertilizer" approach replaces ordinary fertilizers with slow-release or nitrification-inhibitor fertilizers. The "Organic materials" approach substitutes SNF with organic inputs like manure and crop residues. The "Green manure" approach uses legume and grass species plowed into the soil. Nitrogen input was calculated using N efficacy rates from literature or a web app that estimates N mineralization based on weather and organic material type. Many of the sources are based on the reports written in Japanese, and the titles of the documents are listed in Japanese. The bib file contains information on the online links for each source.