###### Abstract  
This study investigates soil volatilomics as an innovative approach to assessing the impact of land use on soil quality. This research addresses the critical need for sensitive diagnostic tools to distinguish subtle biochemical variations in soils influenced by different land use management practices. Soil samples were collected along a land use transect in Cluj County. Their volatile organic compounds were extracted by headspace solid-phase microextraction (HS-SPME) followed by a gas chromatography-mass spectrometry (GC-MS) analysis. A multivariate statistical method was used to differentiate the volatilome profile. Among the 106 detected compounds, oxygenated species dominated across all land uses, with the highest concentrations in forest soils (77%), followed by grasslands (71%) and agricultural soils (65%). Principal component analysis revealed distinct clustering patterns, with the first two components explaining 72.8% of the total variance (PC1: 41.7%, PC2: 31.1%). Supervised PLS-DA modeling demonstrated robust land use discrimination, achieving AUC values of 0.868 for agricultural versus forest comparisons and 0.810 for both forest versus grassland and grassland versus agricultural comparisons. The volatilome diversity analysis indicated that grasslands contained the highest number of distinct compounds (64), closely followed by forest soils (63), while agricultural soils showed reduced diversity (51). These key findings revealed distinct volatile signatures, with forest soils exhibiting the highest complexity and agricultural soils demonstrating a more homogeneous profile, whereas grassland soils presented high internal variability. These results underscore the potential of soil volatilome profiling as a sensitive indicator of the effects of land use on soil biochemical processes and support the utility of soil volatilomics in sustainable land management and ecosystem monitoring. osil volatilomics; organic compounds; multivariate statistics; soil health; mass spectrometry +
Footnote †: journal: _Appl. Theor. Phys. A:_  
**2025**, 12, 92  
**2025**  
**2025**  
maintain relatively high levels of soil organic matter and microbial diversity [6; 7], although the risk of overgrazing may induce soil compaction and further nutrient depletion [8]. Forest ecosystems, which benefit from a continuous supply of organic litter and complex root architectures, typically support enhanced organic carbon sequestration [9], improved soil structural stability [10], and robust nutrient cycling [11; 12]. These different effects underscore the essential role of land use in shaping soil functionality and ensuring long-term ecosystem sustainability. Recently, the soil volatilome has attracted attention as a highly sensitive indicator of the chemical and biological status of soils under various pressures [13; 14]. Volatile substances arise from a range of biological processes, including organic matter degradation, nutrient turnover, and complex microbial metabolism [15]. First, they can be considered to be sensitive health indicators, reflecting complex biochemical and ecological interactions. Second, soil volatile organic compounds actively participate in nutrient cycling, microbial activity, and plant-microbe communication [12]. Characteristic volatile markers--such as terpenoids, short-chain alcohols, aldehydes, and volatile sulfur compounds--have been linked to key processes; for example, specific terpenoids correlate with fungal community dynamics and organic matter content, while alcohols and aldehydes may indicate active decompositions [14]. Recent advances in analytical chemistry have enabled the detailed characterization of soil volatilome profiles, enhancing our understanding of their role in soil quality [15]. A growing amount of evidence suggests that soils with superior ecological quality exhibit a richer and more diverse volatilome profile, mirroring the complex interplay of biodiversity components' influences [15].