Abstract

Water security represents a major challenge in East Africa, affecting the livelihoods of millions of people and hindering sustainable development. Predicted increases in rainfall intensity and variability are expected to exacerbate water insecurity and land degradation. Improving soil infiltrability is an effective strategy for addressing water insecurity and land degradation. Research on soil infiltrability is often highly localized; therefore, scientific understanding of the drivers of infiltrability on larger spatial scales is limited. The aim of this study was to understand the main drivers of infiltrability across five contrasting landscapes in Kenya. We measured field-saturated hydraulic conductivity (K_fs) in 257 plots and collected data for variables representing soil properties (sand content, soil organic carbon (SOC) and pH), land degradation (grazing pressure and presence of erosion), vegetation quantity (woody aboveground biomass), and vegetation quality (functional properties and diversity). We used generalized mixed-effects models to test for the effects of these variables on K_fs. Median K_fs for the five sites ranged between 23.8 and 101.8 mm h⁻¹. We found that K_fs was positively associated with sand content (standardized effect 0.39), SOC content (0.15), and functional diversity of woody vegetation (0.09), while it had a negative relationship with the presence of erosion (−0.24) and grazing pressure (−0.09). Subsequently, we conclude that infiltrability can be enhanced through using land restoration strategies which specifically target parameters that affect K_fs. The results further support that K_fs is not solely dictated by inherent soil properties, and that management interventions which boost SOC, reduce erosion, and minimize unsustainable grazing can help address water scarcity by restoring soil hydrological function.

Keywords

Kenya; Infiltrability; Land degradation; Functional diversity; Water security; Soil organic carbon

Published in

Science of the Total Environment
2023, Volume: 907, article number: 168038

SLU Authors

• Falk, David

  • Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
    
  • World Agroforestry (ICRAF)

• Ilstedt, Ulrik

  • Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
    

• Bargues Tobella, Aida

  • Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
    

Sustainable Development Goals

Ensure availability and sustainable management of water and sanitation for all
Protect, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification, and halt and reverse land degradation and halt biodiversity loss


UKÄ Subject classification

Soil Science


Publication identifier

DOI: https://doi.org/10.1016/j.scitotenv.2023.168038

Permanent link to this page (URI)

https://res.slu.se/id/publ/126657