Carbon stock and mineral factors controlling soil organic carbon in a climatic gradient, Golestan province

Abstract

Organic matter content of the many soils is less than 5% by weight; nevertheless this small amount of organic matter (OM) has a significant impact on soil properties. A study to evaluate the role of climate in distribution of organic carbon (OC) and mineral factors (such as soil composition, soil stability and clay minerals) controlling OC was performed. Seven surface soils were collected (0-20 cm depth) with three replications in a climate gradient (200 to 800 mm of rainfall). The results showed that aggregates < 0.053 mm in most of the soils had the lowest organic matter content (Figure 2), and carbon stock increased with increasing in the aggregates size in most soils. There was no significant relationship between OC content and clay mineral content, but there was significant relationship for illite and chlorite. It can therefore be deduced that OC stock is probably controlled mainly by climate factor than clay minerals. Oxalate iron was positively related to OC content, but this relationship does not apply for dithionite iron. The relationship between soil OC content and specific surface area (SSA, g m -2 ) of the soil was positive and significantly correlated. Labile soil OC content had a positive relationship with the climate index (P/ET°). As the index increased the potential loss of OC content increased, as well. Labile OC content was estimated between 0.49 to 16.64 g kg -1 and a potential loss of OC was between 1.28 to 46.12 Mg of carbon per hectare on the soil surface horizon.

Modeling soil cation exchange capacity in multiple countries

“…In contrast, CEC was primarily associated with OC content in Spain, as has been seen in other studies (Khaledian et Khaledian et al Catena 158 (2017) 194-200 different results were observed in this study in the agriculture, forest and Iran categories. These results indicated that soil CEC was more strongly controlled by clay than soil OC, as described by Zeraatpishe and Khormali (2012). The different behavior of the soils in Spain might due to the changes in soil properties triggered by long-term intensive agriculture, which changed the soil properties due to ploughing and the use of pesticides.…”

“…Ghorbani et al (2015) concluded that silt has less impact on the estimation of soil CEC than clay and sand. High amounts of OC can affect soil pH and, therefore, CEC (Zeraatpishe and Khormali, 2012). In addition, SOM, which is strongly correlated to OC, has a high CEC per unit volume (Brady and Weil, 2008).…”

Effect of cover crops on physico-chemical attributes of soil in a short-term experiment in the southwestern Amazon region

“…This is due to the fact that the use of plants and straw influences the biological dynamics of soil (Franchini et al, 2007), with positive effects on overall fertility, especially in levels of soil organic matter after a few years (Maia et al, 2013). The application of organic matter to the soil over time, improves the physical and chemical conditions, specific surface area, soil stability (aggregate size) and soil organisms (Zeraatpishe and Khormali, 2012;Khaledian et al, 2013).…”

Seasonal variations and source apportionment of complex polycyclic aromatic hydrocarbon mixtures in particulate matter in an electronic waste and urban area in South China

“…In contrast, at the rural e-waste site there was a negative correlations between the PM and OC concentrations (r = -0.331, p = 0.010), but the EC contents varied less with PM (p = 0.755). This implied that the increase of PM in the rural air could be contributed largely by mineral particles from soils, which usually have lower organic matter content (less than 5%) (Zeraatpishe and Khormali, 2012). Alternatively, this could also be attributed to the low OC content particles released from e-waste recycling or to secondary inorganic ions that have been found to be significant components of PM.…”