Abstract

Recent estimates show that one third of the world's land and water resources are highly or moderately degraded. Global economic losses from land degradation (LD) are as high as USD $10.6 trillion annually. These trends catalyzed a call for avoiding future LD, reducing ongoing LD, and reversing past LD, which has culminated in the adoption of Sustainable Development Goal (SDG) Target 15.3 which aims to achieve global land degradation neutrality (LDN) by 2030. The political momentum and increased body of scientific literature have led to calls for a 'new science of LDN' and highlighted the practical challenges of implementing LDN. The aim of the present study was to derive LDN soil organic carbon (SOC) stock baseline maps by comparing different digital soil mapping (DSM) methods and sampling densities in a case study (Otjozondjupa, Namibia) and evaluate each approach with respect to complexity, cost, and map accuracy. The mean absolute error (MAE) leveled off after 100 samples were included in the DSM models resulting in a cost tradeoff for additional soil sample collection. If capacity is sufficient, the random forest DSM method out-performed other methods, but the improvement from using this more complex method compared to interpolating the soil sample data by ordinary kriging was minimal. The lessons learned while developing the Otjozondjupa LDN SOC baseline provide valuable insights for others who are responsible for developing LDN baselines elsewhere.

Keywords

land degradation neutrality; sampling density; map accuracy; method complexity; soil organic carbon; Namibia

Published in

Sustainability
2018, Volume: 10, number: 5, article number: 1610
Publisher: MDPI

SLU Authors

• Persson, Kristin

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    
  • International Center for Tropical Agriculture (CIAT)

• Söderström, Mats

  • Department of Soil and Environment, Swedish University of Agricultural Sciences
    
  • International Center for Tropical Agriculture

Sustainable Development Goals

SDG15 Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss
SDG16 Promote peaceful and inclusive societies for sustainable development, provide access to justice for all and build effective, accountable and inclusive institutions at all levels


UKÄ Subject classification

Soil Science


Publication identifier

DOI: https://doi.org/10.3390/su10051610

Permanent link to this page (URI)

https://res.slu.se/id/publ/95893