# TerrHum

> Mobile field guide for classifying terrestrial forest topsoils and humus forms. (iPhone/iPad app by Augusto Zanella.)

- Source: https://appshunter.io/ios/app/terrhum/id1366575503 (this page in markdown: same URL + `.md`)
- Developer: [Augusto Zanella](https://appshunter.io/developer/1366575502)
- Category: Education
- Price: Free
- Rating: 4.00/5 from 1 App Store ratings
- Age rating: 4+
- Requires: iOS 10 · 18 MB
- Languages: American English, French (France), Italian
- Released: 2018-06-29
- Data updated: 2026-07-04
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/terrhum/id1366575503/reviews.md

## What is TerrHum?

TerrHum is a University of Padua free app that allows the main content of a field guide to be stored on a cell phone. The name TerrHum is an abbreviation of the words “Terrestrial” (not hydromorphic, not submerged) and “Humipedon” (organic and organic-mineral soil horizons).
With this application, it is possible to classify all non-submerged forest topsoils of our planet. The app is built on the indications about humus forms and systems reported in eight scientific articles collected in an Applied Soil Ecology special issue entitled Humusica 1 (Zanella, A., Ascher-Jenull, J., 2018. Editorial. Appl. Soil Ecol. 122, 1–9. doi:https://doi.org/10.1016/j.apsoil.2017.11.029). 
The articles are the fruit of many years of researches and meetings of a Humus Group gathering more than 50 soil ecologists, biologists, and naturalists.
Once all figures (about 150) have been opened a first time (with a fiber connection, the download of all the figures takes few minutes), the iOS device on which the application has been downloaded does not need to be connected to the Internet to run the application. The recall through touch-buttons of photographs allows a classification of the humus forms and the main groups of animals that live there even for beginners.

Let us consider a user faced with a soil profile to be classified. A cubic volume of 50×50×50 cm is generally sufficient for studying humus systems and forms in a forest environment, while a larger hole or many well-distributed small holes are necessary for surveying a heterogeneous area. As a humus form is made of superposed humus horizons, the app asks the user to indicate one-by-one which types of humus horizons are present in the observed profile. The user is asked to answer a series of YES/NO questions. He can use the touch-buttons for help and display examples of horizons, types of transition or humus systems, as well as forms and tables of composition/classification of humus horizons, or groups of animals and droppings. At the end of the survey, a photograph of the target humus form appears, along with a list of the chosen horizons. 

By clicking/touching on the screen, each photograph may be magnified. A caption that appears at the bottom of the picture provides access to the morpho-functional features of the soil profile that lead to the result: the final classification of the humus system. The app is freely downloadable and in continuous evolution (automatic update). To contribute to its improvement, simply send your suggestions, photographs, schemes, etc. to: augusto.zanella@unipd.it. Your name will be reported alongside a photograph or a relevant improvement, as in an open source app. 

Information about the topsoil classification and indications about the topsoil functioning are given in Humusica 1, articles 1, 2 and 3. Supplemental specific information about diagnostic horizons and humus forms may be found in Humusica 1, articles 4, 5 and 6. Sampling panel and pedofauna are illustrated in Humusica 1, articles 7 and 8.

Humusica 1 articles here: https://www.sciencedirect.com/journal/applied-soil-ecology/vol/122/part/P1.
Corresponding author: augusto.zanella@unipd.it

## Key features

- Classify forest topsoils
- Identify humus forms and horizons
- Offline functionality
- Visual examples and guides
- User-friendly YES/NO questions
- Magnifiable photographs


## Frequently asked questions about TerrHum

### What is TerrHum used for?

TerrHum is a mobile application designed to help users classify non-submerged forest topsoils and identify humus forms. It provides a guided process with visual aids for accurate identification in the field.

### Does TerrHum require an internet connection to use?

Once all the main content figures are downloaded with a fiber connection, TerrHum can be used offline. This makes it a convenient tool for fieldwork where internet access may be limited.

### How does TerrHum help users classify soils?

TerrHum guides users through a series of YES/NO questions about the observed soil profile. It offers touch-buttons for help, displaying examples of horizons, humus systems, and animal groups to aid in classification.

### What kind of information does TerrHum provide?

The app provides information on humus forms, soil horizons, and the main groups of animals that inhabit them. It also offers access to morpho-functional features of the soil profile that lead to the final classification.

### Is TerrHum suitable for beginners?

Yes, TerrHum is designed to be useful even for beginners. The recall through touch-buttons of photographs and the guided question system make the classification process accessible.

### How often is TerrHum updated?

TerrHum is in continuous evolution and receives automatic updates. Users can contribute to its improvement by sending suggestions and photographs to the developer.

### What devices does TerrHum support?

TerrHum is available for iOS devices, including iPhone, iPad, and iPod. It is rated for ages 4 and up.

### Does TerrHum have ads?

No, TerrHum does not contain advertisements. It is a free application developed by the University of Padua.

## Version history (last 5 releases)

### 2.0 — 2022-01-22

- Add French & Italian
- New images

### 1.3.1 — 2020-07-06

Enlarged to semiterrestrial humus systems (peats & moors)

### 1.3.0 — 2019-04-29

The Yes/No key has now photos !

### 1.2.0 — 2019-04-22

Various fixes

### 1.1 — 2018-06-12

- New icon
- Minor fixes

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