I have 250 m soil map from SoilGrids. I need to extract the soil type for some districts to perform land suitability analysis. But not sure how reliable are they?. Any suggestions?
Reliability is derived from your beliefs, so there is no correct answer to this. All of the information behind the SoilGrids is linked from their site; you will have to decide for yourself it if is reliable enough. It seems like it, but this isn't my project.
SoilGrids data comes from the SoilInfo app, which you can find more about in the SoilsInfo app icon in the navigation.
SoilInfo app's about page goes into detail about its purpose and how the data is acquired.
SoilInfo app is the mobile component of the Global Soil Information Facilities (GSIF), and exists to provide access to the data behind SoilGrids.
More information at these links:
GSIF - Our Approach for Generating Open Soil Data
SoilInfo App — global soil data on your palm
SoilGrids — global gridded soil information
WoSIS Soil Profile Database