Organic carbon stocks in Mediterranean soil types under different land uses (Southern Spain)

Abstract

Abstract. Soil C sequestration through changes in land use and management is one of the sustainable and long-term strategies to mitigate climate change. This research explores and quantifies the role of soil and land use as determinants of the ability of soils to store C along Mediterranean systems. Detailed studies of soil organic C (SOC) dynamics are necessary in order to identify factors determining fluctuations and intensity of changes. In this study, SOC contents from different soil and land use types have been investigated in Andalusia (Southern Spain). We have used soil information from different databases, as well as land use digital maps, climate databases and digital elevation models. The average SOC content for each soil control section (0-25, 25-50 and 50-75 cm) was determined and SOC stocks were calculated for each combination of soil and land use type, using soil and land cover maps. The total organic C stocks in soils of Andalusia is 415 Tg for the upper 75 cm, with average values ranging from 15.9 Mg C ha −1 (Solonchaks under "arable land") to 107.6 Mg C ha −1 (Fluvisols from "wetlands"). Up to 55 % of SOC accumulates in the top 25 cm of soil (229.7 Tg). This research constitutes a preliminary assessment for modelling SOC stock under scenarios of land use and climate change.

Organic matter dynamics along a salinity gradient in Siberian steppe soils

“…Larger OC stocks in salt-affected soils than in Kastanozems are also in contrast to earlier work, which found a negative effect of salinity on soil OC stocks (reviewed by Wong et al, 2010). Possible reasons for the observed differences are climatic variations between the studies (strong aridity in the Spanish Solonchaks from Muñoz-Rojas et al, 2012) or alterations in soil texture (finer textured Kastanozems in the study from Bischoff et al, 2016), which may change the soil water balance and thus plant growth and soil OC inputs. However, it appears that the covarying moisture gradient along the salinity transect is a better explanation for the observed differences.…”

“…With average OC stocks of 70.9 ± 2.8 Mg ha −1 in 0-100 cm of depth for the Kastanozems, the values were clearly below those observed by Batjes (1996) and calculated from Bischoff et al (2016). On the other hand, average OC stocks of 94.2 ± 6.9 and 129.5 ± 25.6 Mg ha −1 in 0-100 cm of the non-sodic Solonchaks and Sodic Solonchaks, respectively, were clearly above the values reported by Batjes (1996) and Muñoz-Rojas et al (2012). Larger OC stocks in salt-affected soils than in Kastanozems are also in contrast to earlier work, which found a negative effect of salinity on soil OC stocks (reviewed by Wong et al, 2010).…”

“…Muñoz-Rojas et al (2012), for example, reported soil OC stocks in the Solonchaks of southern Spain in 0-75 cm depth as 53.6 Mg ha −1 (coefficient of variation (CV): 60 %) under shrub and/or herbaceous vegetation. Batjes (1996) calculated in the framework of a global meta-analysis an average soil OC stock in Solonchaks of 42 Mg ha −1 (CV: 67 %) in 0-100 cm of depth, while he noted that Mollic Solonchaks had particularly larger soil OC stocks of 101 Mg ha −1 (CV: 44 %).…”

Impacts of land use change in soil carbon and nitrogen in a Mediterranean agricultural area (Southern Spain)

“…Many authors had applied the SR methodology (Franzluebbers, 2002), in most cases using control sections (Muñoz-Rojas et al, 2012b), in other cases using the entire soil profile (Corral-Fernández et al, 2013). When control sections are used, similar soil thickness can be compared between them, however, if the entire soil profile were used especially to study land uses and/or management changes for a long time, these comparisons can be more complicated.…”

Changes in soil quality after converting <i>Pinus</i> to <i>Eucalyptus</i> plantations in southern China

“…Many studies have focused on soil physic-chemical properties (Garay et al, 2004;Muñoz-Rojas et al, 2012;Parras-Alcántara et al, 2013), microbial communities (Wu et al, 2012) or enzyme activities (Wang et al, 2008), which only reflect some aspects of soil quality. A soil quality index (SQI) was proposed for quantifying the combined biological, chemical and physical response of soil to land use and soil/crop management practices (Andrews and Carroll, 2001;Andrews et al, 2002).…”