Interactions between wind erosion and soil organic carbon

ITURRI, L.A.; BUSCHIAZZO, D. E.

Agricultural soil sustainability and Carbon Management

Elsevier B.V.

Lugar: Amsterdam; Año: 2023;

Wind erosion is a common soil degradation processes in semiarid and arid environments of the world that can affect the C cycle by decreasing soil C stocks. It is also known that soil organic C contents (SOC) can theoretically modify the susceptibility of the soil to be eroded by the wind as it influences the soil aggregation. In this chapter, the role of SOC as a driven factor of wind erosion and the effect of wind erosion on SOC losses are analyzed. The effect of SOC on soil erodibility has been widely analyzed. The best index of soil erodibility is the proportion of aggregates smaller than 0.84 mm, the erodible fraction (EF). It has been demonstrated that soil texture is the main factor affecting EF of most studied soils, being the sand and clay fractions the determining variables. These studies also indicated that SOC has a secondary role in determining EF and only in few cases CaCO3 amounts, rather than soil texture, is the main factor affecting EF. The effect of wind erosion on the C cycle has been less investigated. We analyzed here the C accumulations in sediments transported by the wind in two different ways: saltation and suspension. This is because, though both transport processes occur simultaneously during wind erosion events, most of the sediment mass is transported by saltation representing suspension the lowest mass proportion. The sediments transported by saltation have coarse textures (mostly > 90um in diameter), are mobilized below 1 m height and at short distances (some meters), while the sediments moving by suspension have finer textures, are mobilized at high heights and at long distances (up to thousand km). These characteristics makes saltation to be more linked with the degradation of the eroded soils while suspension is a concern because of its possible negative environmental effects, including human health (particularly through the concentration of particles smaller than 10um in diameter, PM10). Because of this, we analyzed here the accumulation of C in sediments transported by both, saltation and suspension, in order to analyze their potential effects on soil degradation and the C cycle in the environment, respectively. The main results indicated that the low dense organic compounds with high C concentrations like plant debris and polysaccharides of microbial origin, were preferentially transported at high heights while those of high density like carboxylic acids, ketones and aldehydes, were transported at low heights. Tendencies of C distribution in height in different textured soils are also presented