Figure 2. Organic carbon (OC) content (%) in PM10 and OC enrichment
ratio (ER) as a function of OC content in the soil. AG: agricultural
soils for grain production; AFG: agricultural soils for forage and grain
production; RRI: rural roads inside farm fields; RRO: rural roads
outside farm fields. **Statistically significant (p<0.01)
The OC ER was positive in all rural soils studied (Fig. 2). Other
studies also found positive OC ER in the PM10 and in the fine fractions
transported by the wind (Iturri et al., 2017; Mendez et al., 2017; Webb
et al., 2012). The OC ER was associated to the OC in the soil, and it
was described by a negative potential function (Fig. 2). Soils with low
OC contents (rural roads) showed high ERs and soils with high OC
contents (agricultural soils) showed low ERs. OC content in soils of
rural roads was low (Fig. 1) and most of the OC was associated to the
PM10 (Fig. 2). The low OC content in soils of rural roads can be
attributed to the absence of a continuous supply of labile OC (due to
lack of vegetation) and high rates of wind erosion (Ramirez Haberkon et
al., 2021). In rural roads, OC tends to accumulate in PM10, which
represents the stable fraction of OC that is protected chemically and
physically (Hassink, 1997). The stable fraction of OC is less sensitive
to soil management and wind erosion (Webb et al., 2012). Vegetal
coverage in agricultural soils played a crucial role in preventing the
loss of labile OC through wind erosion, while also facilitating the
accumulation of labile OC in the soil.
Conclusions
Our study revealed important findings regarding the OC content in PM10
emitted by agricultural soils and rural roads. This study provides the
first report on the OC content in the PM10 emitted by rural roads in the
region. The OC content in the PM10 was consistently higher than that in
the soil across all soils analyzed, indicating an enrichment of OC in
the PM10. This finding aligns with previous studies demonstrating the
accumulation of OC in fine particles.
This study reveals an association between organic carbon (OC) content in
PM10 and OC content in the soil. An association between OC ER and OC
content in the soil was also found. Both associations indicate that OC
accumulates in PM10 until it reaches a maximum (Saturation), which was
found to be 3.5% for the analyzed soils. These findings enhance our
understanding of the dynamics of OC in PM10 and its association with the
OC content in the soil. Our study highlights the importance of
considering the OC content in the PM10 emitted by rural soils for
quantifying OC losses from the soil and OC discharges into the
atmosphere through dust emissions. Further investigations should examine
the OC content in PM10 emitted by rural soils across diverse soil
textures and geographical regions.