## 2 Materials and Methods
### Wind Erosion  
Wind erosion, affecting about 550 million hectares of the global land area [11; 39], is caused by aeolian (or eolian) processes. The term \"aeolian\" is derived from the Greek god \"[PERSON]\", the keeper of the wind. Wind erosion is strongly affected by soil texture. Soils most susceptible to wind erosion may have \(<\)5% clay and \(<\)3% silt, and \(>\)50 cm deep surface layer [22]. Wind erosion may create 500-5000 Tg (million tons) of dust annually with a strong impact on soil properties, air quality, and human health [39; 40; 41]. The environmental impacts of wind erosion during the Dust Bowl Era of 1931 through 1939 are described by [PERSON] [42]. Accelerated erosion affects critical biotic and abiotic processes governing the soil/ecosystem C cycle. The magnitude of the loss of SOC by wind erosion is related to that of the fine soil fraction [43]. The loss of C-enriched fine soil particles depletes its SOC and reduces its future potential to restore the SOC pool. The aeolian erosion process affects both progressive and regressive pedogenesis in dry eco-regions. On agricultural lands, erosion degrades soil quality by removal of silt, clay, and SOC fractions through effective sorting processes that leave behind only coarse sand and gravels [23]. The loss of NPP reduces the plant feedback and aggravates the SOC loss [44]. The wind-blown dust is also enriched in SOC, which may also depend on soil texture. The global estimate of SOC erosion by wind may be as much as 0.3 to 1.0 Pg C/Yr (Table 3) and some highly vulnerable soils may lose 3.6 Mg C/ha per year [32]. Losses of SOC by wind erosion in Northern China are estimated at 0.9 Tg C/yr [45]. The loss of PM10 (particles of \(<\)10 micrometer) adversely impacts soil nutrient reserves [40]. Wind-blown dust is also enriched in SOC and has a high enrichment ratio (Table 4). In Niger, [PERSON] et al. [46] assessed nutrient and C losses in saltation and suspension transport by conducting chemical analysis of the trapped material at 0.05, 0.26, 0.5, and 2 m. The sediments were three times richer than topsoil at 0.5 m and 17 times at 2 m. In Australia, [PERSON] et al. [47] observed that \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Country** & **Experiment** & **Enrichment Ratio** & **Reference** \\ \hline Australia & Rainfall simulation & \(>\)1 & [34] \\ Belgium & Rainfall simulation & 1.2–3.0 & [35] \\ Belgium & Rainfall simulation & 0.9–2.6 & [36] \\ China & Lab studies & 1.3–4.0 & [37] \\ China & Rainfall simulation & 0.98–1.01 & [32] \\ USA & Field experiment under cotton & 8–12 & [38] \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The enrichment ratio of carbon in sediments derived from water erosion. the SOC-enrichment ratio ranged from 2.1-41.9 for a sandy and 2.1 for clayey soil (Table 4). [PERSON] and colleagues hypothesized that in addition to particle size, distribution, and the degree of aggregation, size-selective sorting of SOC during transport may enhance the enrichment of SOC dust emissions. The SOC concentration in two of the dust samples was 15%-20% by weight. A study in China by [PERSON] et al. [48] documented that an increase in the particulate matter emissions (e.g., black earth) from biochar-amended soils may counteract the negative emissions potential of biochar. Magnitude of dust emitted is aggravated by human activities [40]. Both direct and indirect effects of accelerated erosion, especially in arid and semi-arid regions, exacerbate the risks of desertification and drastically increase the already daunting challenge of achieving land degradation neutrality or LDN by 2030 [54, 55]. Soil degradation impacts of accelerated erosion by wind, and its positive feedback to the process of desertification, have strong adverse consequences on Earth systems and human environments [40], as well as on NPP, the input of biomass-C into the soil, and on the disruption of the global C cycle.