Ratio Milpa: Producer Guide (1st edition, version 0.3.0)

English guide for farmers, technicians and survey staff using Ratio Milpa 0.3.0, a free app for a national study of local maize knowledge in Mexico as a complex adaptive system. It walks through the 13 blocks with the worked case of landrace maize in Calpan, Puebla (Díaz-José et al., 2026): the maize (64 races or improved), the locality, the baseline questionnaire with flexible management, regeneration, risk, network and 3D model, sustainability, outlook, report and the national atlas that combines many localities' files without a server. It includes an interview guide, printable field sheets, troubleshooting and a glossary. 1st edition, updated November 2026. The Spanish version (Instructivo del Productor) is a separate record with its own DOI.