Root Distribution of Robinia pseudoacacia for Soil Erosion Mitigation: A FAIR-Compliant Database Approach with NFS-FAIR-DDP

Soil erosion is marked as the most significant, most dangerous, and most widespread type of soil degradation, which is why it appears as a limiting factor in the sustainable use of land and the development of areas, countries, and regions. To avoid huge economic investment for implementing civil engineering works, bio- and eco-engineering techniques have been regarded as one of the most important approaches to combat soil erosion, shallow landslides, and slope instability. Vegetation is vital for preventing soil erosion and shallow landslides, as plant roots stabilize the soil by binding particles together, while the canopy intercepts raindrops, reducing their erosive force. The presence of forests on hillslopes significantly reduces the slopes susceptibility to rainfall triggered shallow landslides. This is due largely to the reinforcement of the hillslope soil by tree roots which increase the shear strength of the soil, and in some instances, anchor the soil mantle to the underlying bedrock by deeply penetrating roots. Hence the aim of this investigation was the investigation of the root distribution of the Black locust (Robinia Pseudoacacia L.), as well as its root tensile strength. Two investigation sites were explored in North Macedonia, Varvara and Techeni Bair localities, with five trees excavated at the former site and four trees at the latter. Four soil samples were taken from both locations, at two depths (20 and 40 centimeters of depth) and subsequently analyzed. The vertical root distribution results showed double the root frequency both at root distribution per dept (vertical), as well as per distance from stem for the Varvara locality. However, this might be due to the soil and climatic factors as the Techeni Bair locality has a clay-loam soil texture, with less soil moisture, whereas the Varvara locality has a sandy texture and higher amount of soil moisture due to it being five to ten meters away from a river. At the lower depth though, the Techeni Bair locality had higher root frequency, which is due to the afore mentioned environmental conditions and the roots need to go deeper to provide the required nutrients. The carried-out root tensile strength results by pullouts of the roots have not been conclusive and will be further investigated. Of the forty pullout tests carried out though, it was apparent that the soil/root interface and friction were not the same for the two localities, with roots being easier to pullout at the Varvara locality even with higher root diameter, whereas at the Techeni Bair locality the tests itself were much more difficult. All information was initially recorded in a spreadsheet but was later converted into a FAIR compliant database by employing the NFS-FAIR-DDP software which produces an SQLite database along with accompanying documentation.