Plants have the ability to capture atmospheric carbon and transform it into organic carbon through photosynthesis and incorporating it into their structures (leaves, branches, roots,...). The remains of the plants are degraded by arthropods, mollusks, etc. But some of this carbon does not degrade and remains in the soil for years in the form of humic acids. Therefore, the soil is a carbon sink and the soil organic carbon is about the 69.8% of biosphere organic carbon (FAO, 2001). The carbon retention and release capabilities depends on its texture, structure, chemical properties, type of humic acids, temperature and humidity, as well as the activity of soil organisms.

Globally, as a result of changes in ecosystems, with increasing deforestation of tropical forests, the proliferation of fires, etc.… this carbon sequestration capacity is altered. Increasing temperatures and the depositing of nitrogen will increase the rate of decomposition of organic matter and decrease the concentration of organic carbon hijacked in the soil.

The Teabag project is part of a global project that uses standardized green tea and rooibos, who are buried in the ground for a certain period of time. This will mean that we will have a measure of the rate of decomposition and the amount of recalcitrant matter that is not decomposed by the action of microorganisms.

To observe the changes in decomposition as a function of temperature, study plots have been established at altitudes ranging from 1,500 to 2,300 meters. The observed changes depend in part on climatic variations in altitude, as well as the characteristics of each locality (vegetation, soil ...).

We foresee that with climate change carbon is released more quickly and carbon retention capacity is reduced.

The bags were in 7 plots located at heights of 100 m between each one. The first three in scot pine forests, the last three in mountain pine and the fourth plot were hybrids of the two pines. All plots have a roughly similar orientation on the north side, remaining on the shady side.

In general, only slight variations are observed, however, which hardly give statistically significant results at different altitudes. Trends are observed that indicate that decomposition rates are lower in high mountains. In 2024 the protocol will be modified slightly and the experiment will be replicated to confirm trends.

Decomposition rate of the 7 plots.