## 4 Discussion  
### Soil Volatilomics in Decoding Complex Land Use-Specific Patterns  
The current study presents a comprehensive investigation of soil volatilome profiles across a land use transect, offering new insights into the qualitative and quantitative variation in soil volatile organic compounds. Our results revealed differences in the soil volatilome profiles among forest, grassland, and agricultural soils (Figures 1 and S1). The lack of significant differences in the physicochemical properties (Table 1) of the cambichernozem soil samples suggests that land use influences the volatile organic compound profile. This finding aligns with data available from the literature, where differences in volatile organic compound content were observed in soils from various land uses and management practices [18,31]. [PERSON] et al. [18] reported that shrublands have a higher content of volatile organic compounds in their soil than Mediterranean oak forests do by almost 65%. These authors linked these differences to the composition of the contrasting plant species in the two ecosystems. Another study that compared the soil volatilome profiles of an urban forest and other urban green areas in Thailand revealed that the forest had a greater biogenic origin and oxygenated volatile organic compound content than other urban green regions did [31]. [PERSON] et al. [32] also reported the prevalence of oxygenated volatile organic compounds. In our study, the content of volatile organic compounds was more intense in forest soils than in the other two land uses (Figure 2). We determined the prevalence of oxygenated volatile organic compounds in the soils of all the studied land uses (65%--grassland; 71%--agricultural land; and 77%--forest). The predominant oxygenated volatile organic compounds in our study were alcohols, accounting for 30-48% of the total amount, followed by ketones, accounting for 14-16% of the total amount. These findings are in line with those reported by [PERSON] [18] and [PERSON] [32]. Although [PERSON] [31] reported that alkanes were the dominant volatile organic compound class in forest soils, accounting for 44-47% of the total amount, in our study, the alkane content was less than 10%, with the greatest amount detected in soils from grasslands (8.5%, Figure S2). Studies in the literature have attributed differences in the profile and concentrations of volatile organic compounds mainly to seasonal variations [18,31] and vegetation cover [32]. However, management practices [16,19] and meteorological anomalies [21,33] have also been reported to influence the soil volatilome profile. In our study, although the profiles of volatile organic compounds differed (Figure 5), in most cases, these differences were predominantly quantitative (Figure S1). This result was similar to that reported by [PERSON] et al. [14], who reported that the content of volatile organic compounds in soil is strongly affected by the intensity of soil management practices. [PERSON] et al. [13] and [PERSON] et al. [14] recommend the use of the soil volatilome profile as a biomarker that could provide insight into the ecological functions and mechanisms of microbiome-microbiome, microbiome-plant, plant-microbiome, and plant-plant interactions under various abiotic and biotic conditions. However, in our study, similar to other studies, the differences in the soil volatilome were predominantly quantitative (Figure S1). We employed a combination of exploratory, supervised, and differential analyses to unravel the dynamics of the soil volatilome profile in the land use transect. The unsupervised exploratory analysis, conducted through PCA and HCA (Figure 3), revealed distinct signature characteristics in the volatilome of each land use type. The volatile profiles of agricultural soils were highly consistent, suggesting that anthropogenic management practices may homogenize soil biochemical processes. This observation aligns with the findings of [PERSON] et al.