Organic carbon stocks in the soils of western Hungarian forests

One of the most important causes of global climate change is the increased CO₂ content of the atmosphere. The most important CO₂ sinks on Earth are terrestrial ecosystems, particularly forests, whose organic carbon reserves are stored approximately half in the soil in temperate zones. By changing land use, we have the opportunity to increase carbon dioxide and carbon sequestration. In our research, we investigated the possibility of increasing carbon sequestration in the Austrian-Hungarian border region, primarily through geoinformatics data processing. To validate the geoinformatics data, we measured the amount of organic carbon stored in the soil in 40 forest stands in the area.

 

In the selected forest stands, we took samples every 10 cm from the top 40 cm layer of soil to determine the organic carbon content. During sampling, we took both undisturbed and disturbed samples. In addition to soil samples, we also took litter samples and recorded forest stands. The samples were examined in the soil science laboratory of the University of Sopron.   

 

The pH of the examined soils ranged from 3.9 to 8.1 pH_(H2O). The average pH of the individual layers, from top to bottom, was 4.93, 4.78, 4.84, and 4.97 pH_(H2O).As the results show, the top layer of soil was affected by leaching. We also examined the physical properties of the soil by the proportion of silt+clay particles that ranged from 11 to 65%, with an average of 43.55, 44.95, 46.78, and 48.45% from top to bottom. Loam was the main physical texture, and due to clay migration, the clay content increased downward, but there were also layers with coarse sand physical texture. The physical composition of the soils depended largely on the bedrock. The organic matter content (SOM) of the soil layers examined ranged from 0.54 to 2.16%. Naturally, the higher values were found in the top 10 cm layer, while the lower values were found between 30 and 40 cm. The amount of organic carbon stored in the top 40 cm layer of soil varied between 16 and 81 C t/ha, with an average of 44 C t/ha. The bedrock, soil quality, and forest composition greatly influenced the amount. Our data can contribute to the refinement of carbon stock estimates obtained using geoinformatics methods.

 

This research was funded by the Interreg CS4Region (ATHU-0100046) project "Analysis and utilization of natural and technical carbon sinks in the Hungarian-Austrian border region." Some of the tools used in the research were acquired as part of the project "Investigation of the conditions for woody biomass production - GINOP-2.3.3-15-2016-00039".