Environmental Factors Controlling Soil Organic Carbon Stocks in Two Contrasting Mediterranean Climatic Areas of Southern Spain

Abstract

Managing soil carbon requires accurate estimates of soil organic carbon (SOC) stocks and its dynamics, at scales able to capture the influence of local factors on the carbon pool. This paper develops a spatially explicit methodology to quantify SOC stocks in two contrasting regions of Southern Spain: Sierra Norte de Sevilla (SN) and Cabo de Gata (CG). Also, it examines the relationship between SOC stocks and local environmental factors. Results showed that mean SOC stocks were 4·3 kg m−2 in SN and 3·0 kg m−2 in CG. Differences in SOC in both sites were not significant, suggesting that factors other than climate have a greater influence on SOC stocks. A correlation matrix revealed that SOC has the highest positive correlation with clay content and soil depth. Based on the land use, the largest SOC stocks were found in grassland soils (4·4 kg m−2 in CG and 5·0 kg m−2 in SN) and extensive crops (3·0 kg m−2 in CG and 5·0 kg m−2 in SN), and the smallest under shrubs (2·8 kg m−2 in CG and 3·2 kg m−2 in SN) and forests soils (4·2 kg m−2 in SN). This SOC distribution is explained by the greatest soil depth under agricultural land uses, a common situation across the Mediterranean, where the deepest soils have been cultivated and natural vegetation mostly remains along the marginal sites. Accordingly, strategies to manage SOC stocks in southern Spain will have to acknowledge its high pedodiversity and long history of land use, refusing the adoption of standard global strategies. Copyright © 2015 John Wiley & Sons, Ltd.

Agricultural land abandonment in Mediterranean environment provides ecosystem services via soil carbon sequestration

“…The impact of climate on soil development, runoff generation, soil erosion, and plant cover is well-known (Anaya-Romero et al, 2015; Buendia et al, 2016;Cerdà, 1998b;Ochoa et al, 2016), but little is known about its impact on soil organic carbon, and this is why the results shown here shed light into the environmental impact of land abandonment. Our findings confirm the results of other investigations that are summarised in Köchy et al (2015aKöchy et al ( , 2015b and quantified by Pabst et al (2016) in Africa or by Willaarts et al (2016) in the Mediterranean.…”

Estimation of soil organic carbon under different vegetation types on a hillslope of China’s northern Loess Plateau using state-space approach

“…2). The higher SOC stocks in the 0-20 cm soil layer can be related to plant and soil characteristics at the local scale as both factors affect the balance of C input from plant growth and output from plant decomposition (Wu et al 2010;Willaarts et al 2016).…”

“…The accurate estimation of SOC distribution provides essential data for both SOC monitoring and process-based carbon cycle modeling (Lal 2004). Therefore, a clear knowledge on SOC stocks is essential for accurate application of modeling and measurement data in prediction and evaluation of the effects of land-use change on SOC dynamics (Muñoz-Rojas et al 2013, 2015Willaarts et al 2016). …”

“…To better understand this, traditional methods such as linear regression and analysis of variance have been used to estimate SOC at local (Zhang et al 2013;Liu et al 2016), regional (Wang et al 2015b;Willaarts et al 2016) estimated soil water content driven by relevant soil properties and climatic conditions. For SOC estimation, the state-space approach is much better at large scales than the equivalent linear regression (Liu et al 2012;Jia et al 2017).…”

Leguminous species sequester more carbon than gramineous species in cultivated grasslands of a semi-arid area

“…SOC plays a critical role in controlling soil fertility and cropping system productivity and sustainability (Hurisso et al, 2013;De Moraes Sá et al, 2015), particularly in lowproductivity arid and semiarid agro-ecosystems (Behera and Shukla, 2015;Willaarts et al, 2016). To develop farming methods that conserve SOC is therefore of a great importance (Lal, 2004) in this area.…”