TerrHum, an app for the classification of terrestrial humus forms

In 2003, 26 European soil specialists gathered in Trento (Italy), at the Center for Alpine Ecology, to build a classification of humus forms valid for Europe. A first draft of the work is published in 2009. In 2018, a definitive classification is illustrated in several articles published in two Special Issues of the Journal Applied Soil Ecology (122a 122b). Thanks to the help of an Engineer and using the dichotomous key illustrated in the published articles, an application was codified in iOS environment for iPhones and iPads. TerrHum is freely downloadable (App Store). The humus forms correspond to the organic and organo-mineral horizons of the topsoil. Most of the biological activity of the soil takes place in them. They can be seen as "ecologically diverse environments" in which organized living communities live. The application can be used by all people who have some basic knowledge on soil classification. The soils is generally subdivided into layers called "horizons". Every humus form has a well-known sequence of these 3-5 horizons. TerrHum asks to recognize one by one the horizons of an open profile. It asks for example: "Is there an OH horizon?" Touching "YES" or "No" opens another screen with a second question, and so on until the end, where some photographic examples of humus forms display allowing the user to compare the real topsoil to them. If the inexperienced user does not know the horizons of the soil, a button at the bottom of the screen allows him to recall the definitions and photographs of these. Other keys open windows with groups of soil animals, or tables of the general classification, or any sort of other useful information. The app is constantly evolving, and we hope to put an Android version on the web soon.