Tea Bag Index

The aim of this project is to measure the decomposition of organic matter by burying tea bags in the soil.

tea bags, soil, decomposition

The project overview

Area of Science: Natural Sciences
Location: independent of location
Used Devices: without PC/Mobile, with PC/Mobile
Equipment of citizen scientists: Tea bags, computer, GPS, shovel
Activities of citizen scientists: measuring, other activities
Suitable for: Youngsters and adults
Project duration: 01.07.2010 - 31.12.2018
Time to join in: 01.04.2016 - 30.09.2016

Project objective

Decomposition of organic matter is important for the growth and metabolism of plants and soil microorganisms. The process of decomposition releases nutrients from the organic matter that can be used by the soil organisms and plants. It also releases carbon dioxide (CO2) into the atmosphere. A fast decomposition means higher emissions whereas slower decomposition stabilises carbon in the soil. In order to understand the global carbon cycling better, it is important to collect more data on the decomposition rates in different soils. With the Tea Bag Index, data can be collected on a global scale, also from regions where no data is available so far.

How did citizen scientists participate?

Citizen scientists used a simple method to measure decay of organic matter in soils. They needed three green tea bags and three Rooibos bags, which were then buried in the soil (cropland (maize), grassland or forest). After three months, the tea bags were dug up, dried and sent to AGES with background information of the site. In order to deliver good quality data, AGES sent the same kind of tea bags to all participants. For participation, the registration was open until 20th May 2016.

What happened to the contributions of citizen scientists?

The Tea Bag Index (decomposition rate and stabilisation rate) was calculated from the tea bags received. This could be compared to data from other parts of the world. AGES prepared a map of the Austrian results, which made it possible for citizen scientists to compare their results to other locations in Austria.

Prizes and winners

The school class with the highest amount of points won 1,000 Euro for the class fund. The winners of the other two prize categories supported the Tea Bag Index project by choosing from two alternative prizes. More information can be found on the project’s webpage.

Participating and supporting institutions

Österreichische Agentur für Gesundheit und Ernährungssicherheit GmbH (AGES), Abteilung für Bodengesundheit und Pflanzenernährung


Dr. Taru Sandén (Lehtinen)

Project website: www.ages.at/teabagindex

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