Soil organic carbon characterization in a tropical ecosystem under different land uses using proximal soil sensing technique

Abstract

ABSTRACT Unregulated land-use conversion influences soil organic carbon (SOC) storage and sequestration causing fluctuations. As one of the most vulnerable regions to climate-change impact, Caribbean ecosystems require formulation of strong adaptation strategies to cope with the vagaries of climate change. Therefore, understanding SOC dynamics under land-use change is critical. With increasing popularity of proximal soil sensing (PSS), relating obtained signals to properties of interest, could offer time and cost-efficient procedures for characterizing properties. To our knowledge, no investigation has been conducted employing PSS using electromagnetic-induction (EMI) to characterize the spatial dynamics of SOC as a consequence of transitional land-use. Hence, our research broadens the evidence base for the characterization of SOC in island ecosystems. Apparent electrical conductivity (ECa) measured by a DUALEM-1S sensor was used to characterize SOC at 0–0.3 m under different land-uses. Spatial maps showed that EMI was suitable for distinguishing between natural and anthropogenic land-uses, with anthropogenic land-uses generally having higher and more variable ECa values (Quarry = 22.8–30.5 mS m−1, Agriculture = 5.0–11.3 mS m−1, Residential = 39.2–60.0 mS m−1, Forest = 9.3–14.5 mS m−1, Grass = 13.6–17.0 mS m−1). Natural land-uses had better soil quality indicating that SOC controls soil quality and varies in response to land-use.