What is it about?
Decomposition of organic material is crucial for the growth and metabolism of plants and microorganisms: decomposition and mineralisation make the necessary nutrients available. During this process, the greenhouse gas carbon dioxide (CO2) is released into the atmosphere as well. Rapid decomposition leads to increased CO2 emissions, while slow decomposition increases carbon storage in the soil. For a better understanding of the global C cycle, it is therefore important to gather more information about decomposition rates in different soils.
© AGES
With the Tea Bag Index, citizens worldwide can make a valuable contribution to science and the environment: They simply bury tea bags in the ground, dig them up again after 3 months and weigh them. The weight loss indicates how much plant material - in this case tea - has been decomposed. This simple and inexpensive method of determining decomposition rates is scientifically recognised, and corresponding citizen science projects have already been implemented in numerous countries around the world. With these experiments, comparable data can be obtained worldwide, especially from regions where these data have not been available so far.
Tea bag method
© AGES
At the end of this page you will also find a video describing the method in detail.
Would you like to participate?
Interested citizens can join the initiative at any time and help to investigate decomposition processes in the soil. The experiment can be carried out with the TBI app, which was developed in the CS project TeaTime4App in cooperation with the HBLFA Wieselburg and the CS platform Spotteron. The app contains step-by-step instructions for the TBI experiment and the results can be entered directly into the app. Scientists can compare these data worldwide and, for example, analyse the influence of location and soil composition on the rate of decomposition. The TBI app also contains other interesting information and CS activities about soil, e.g. texture by feel, discovering soil animals, observe soil pollution. For further information on the app you can watch the following video (in German):
Results & new materials
The results of the Austrian Citizen Science Award 2016 were published together with the results of a Swedish TBI project in the journal Sustainability. Among other findings, it was shown that decomposition rates in the Pannonian environmental zone were significantly influenced by land use, with decomposition occurring most rapidly in grassland. Stabilisation of labile material was significantly higher in forests than in grasslands and croplands, both in the continental and southern alpine zones.
Soil Sciences Education: Global Concepts and Teaching
The Austrian Tea Bag Index team, together with other soil scientists, wrote the chapter "Good practices in DIY soil activities in Austria" in this text book. The book offers a collection of tried and tested methods from different countries around the world to make students aware of soils and their importance. The chapter by the Austrian scientists contains e.g. instructions for a workshop with the TBI activities in class and experiments on the filter function of soil.
Final report of the TeaTime4Schools project
In this project, 150 schools in Austria conducted the TBI experiment and the HBLA Klosterneuburg dealt with the topic more intensively. You can download the report here (in German). The data from TeaTime4Schools was analysed in this scientific article. The results clearly show how important the participation of citizen scientists and their data collection is for the creation of scientific knowledge.
UN Sustainable Development Goals (SDGs)
The TeaTime4Schools project supported the SDGs and taught students about the importance of these goals. In addition, the activities of the TBI app support the implementation of the SDGs (esp. 2, 13 and 15). The SDG brochure can be downloaded here (in German).
Roles in the project
- Tea Bag Index Team (AGES): Overall coordination of the project including data management
- Project participants (Citizen Scientists): data collection and processing based on their own interests
Tea Bag Index on Social Media
If you are interested in participating in the project, please contact the global Teatime4Science project team or send an e-mail to the local partners: This email address is being protected from spambots. You need JavaScript enabled to view it.
Funded by:
SPOTTERON - Plattform für Citizen Science Apps