Angelini ME, Rodriguez Lado L, Luotto I. 2023. GSNmap Training Mapping soil nutrients and associated soil properties. https://drive.google.com/drive/folders/1ZVcS78nuRCiFUXdIbAVyQ33eVIXvV3R2
FAO. 2022a. Technical Manual for Global Soil Nutrient and Nutrient Budgets map (GSNmap). Rome: FAO; [accessed 2022 Oct 14]. https://fao-gsp.github.io/GSNmap-TM/
FAO. 2022b. FAO’s Global Soil Partnership kicks start a country-driven process to map soil nutrients and soil nutrient budgets at all scales. FAO Highlights. https://www.fao.org/global-soil-partnership/resources/highlights/detail/en/c/1601502/
FAO. 2022c. Country guidelines and technical specifications for global soil nutrient and nutrient budget maps. Rome: FAO; https://doi.org/10.4060/cc1717en
|Total Nitrogen |ppm |Dumas dry combustion method (FAO, 2021a) or Kjeldahl method (FAO, 2021b) |0-30 cm |preferably 2017–2022 | |Available Phosphorus |ppm |Bray I and II, Mehlich I, Olsen (FAO, 2021c; FAO, 2021d; FAO, 2021e) |0-30 cm |preferably 2017–2022 | |Available Potassium |ppm |Mehlich III (Mehlich, 1984) |0-30 cm |preferable 2017–2022 | |Cation exchange capacity |cmolc/kg |Ammonium acetate (Schollenberger and Simon, 1945) |0-30 cm |1980–2022 | |pH | |Soil pH in H2O, KCl, CaCO2 (FAO, 2021f) |0-30 cm |1980–2022 | |Clay (< 2 µm) |g/100g |Hydrometer (e.g. Bouyoucos, 1962) |0-30 cm | | |Silt (2–20/50 µm) |g/100g |Hydrometer (e.g. Bouyoucos, 1962) |0-30 cm | | |Sand (50–2000 µm) |g/100g |Hydrometer (e.g. Bouyoucos, 1962) |0-30 cm | | |Soil organic carbon |% |Dumas dry combustion, Walkley-Black, Tyurin spectrophotometric (FAO,2019a; FAO,2019b; FAO, 2021g) |0-30 cm |preferably 2000–2022 | |Bulk density |g/cmm3 |Overview of methods provided by Blake (1965) |0-30 cm | |