Scholarship allowed to deepen the study of the dynamics of the air regime of forest soils

Hochschule für angewandte Wissenschaft und Kunst (HAWK)a prestigious institution in the area of ​​forestry sciences and natural resources located in Göttingen, Germany, received -through the Re-invitation Program for former Scholarship Holders of the German Academic Exchange Service (DAAD)- Dr. Óscar Thiers, academic from the Institute of Forests and Society of the Faculty of Forest Sciences and Natural Resources of the Austral University of Chile, for a short stay.

The project that the teacher developed at HAWK focused on the study of the dynamics of the air regime of forest soils, specifically the determination of the concentration of CO2 in the surface soil, using developed instruments -still in the testing stage- for this purpose. by German researchers.

“HAWK colleagues have been working on this topic for years, developing methodologies and instruments to make reliable and efficient measurements, as well as looking for new fields of application. The stay allowed me to participate in field work under forest conditions and in urban park conditions (green areas). In the same way, I was able to work in the laboratory with instruments or models associated with the subject”, explained Dr. Thiers.

It is worth mentioning that the HAWK is located next to the Georg-August University, an institution that has collaborated for decades with the Faculty of Forest Sciences and Natural Resources of the UACh, and both also maintain links at the research level with the Max Planck Institute.

Project

According to what was explained by Prof. Thiers, the air regime, as part of the concept of soil fertility, is relevant to analyze the existence and root growth in a given volume of soil, both in forest plantations and in different conditions. of natural forests.

“Soil air is found in the pore space of the soil, mainly coarse pores, being a determining factor in the composition and growth of forest species. The thick pores show different types or proportions of gases: O2, CO2, CH4, among others. Thus, changes in the characteristics or properties of the soil, mostly associated with changes in its structure derived from the intensity of use, will generate effects on the composition and dynamics of gases and, subsequently, positive or negative consequences on the functions of the soil. I usually. One of the key aspects is the presence and condition of roots and their distribution in the soil profile, as a relevant indicator of the quality of the air present in the soil and the consequences for the productivity and vitality of the vegetation”, he pointed out.

The determination of the concentration of CO2 in the soil is normally carried out with a gas chromatograph, using undisturbed soil samples under laboratory conditions. For determinations under field conditions, portable chromatographs are used. However, these determinations are mostly one-off, expensive, and time-consuming. The HAWK task force, led by the Prof. Dr. Thorsten Gaertigdevelops and tests an instrument (Soil CO2-Apparatus) to measure soil CO2 in situ in real time, store the information in a microprocessor and make the information available for subsequent analysis using specific software.

“Regarding my work, I had the opportunity to make determinations in the field with this new instrument. The determinations made and the results obtained provided comparable and precise values ​​with respect to traditional instruments (portable chromatograph), but with lower cost and shorter times. However, these determinations require complementary measurements: soil moisture, the type of structure and the vitality of the roots, among others”, he added.

His evaluation of the stay is positive, not only because of the experience of actively participating in a research project supporting the development of new and original methodological approaches, but also because of the contact with academics and undergraduate and graduate students. For example, at the doctoral level, he worked with a student in the design and field execution of C02 measurements in the soil with different instruments and under different conditions of use: forest with and without forestry management, in addition to analyzing the state of conservation of the extraction routes derived from forest harvesting.

Additionally, together with the project team, he attended the Annual Congress on Arboriculture where topics related to the management and conservation of urban trees, stress due to water deficit and tree diseases, and management of the root zone in tree species were discussed.

“With the work done during my stay, related to the performance of the probe to determine CO2 in the soil, we prepared a paper for the 29th Congress. Baumpflegetage next year 2023 in Augsburg, which has already been reviewed and accepted to be incorporated into the main presentations”, he indicated.

Óscar Thiers thanked the German Academic Exchange Service (DAAD) for providing the funding for his stay, as well as the entire project team: Prof. Dr. T. Gaertig, Dr. Katharina Weltecke (www.bodenundbaum.de) and M.Sc. Oliver Löwe, “for his support and the excellent disposition for my stay”.

“I also appreciate the excellent reception and willingness for future work of the Dean, Prof. Dr. Helge Walentowski.”

“Lastly, and not least, this internship allowed me to continue learning about different aspects, both at the level of academic institutions and the people with whom we will undoubtedly interact in the years to come,” he said.