Soil Water Repellency and Food Security in a Changing Climate

A recent study published in Geoderma by Payton Davis and Dara M. Park from Clemson University explores the significant impact of soil water repellency (SWR) on food security in the context of climate change. This systematic review and meta-analysis reveal how SWR, exacerbated by warmer temperatures and dry conditions, can profoundly affect soil health and crop productivity.

SWR is primarily caused by hydrophobic organic compounds that reduce soil wettability, infiltration, and hydraulic conductivity, ultimately leading to decreased plant-available water and reduced crop yields. The phenomenon results in uneven water distribution, delayed seed emergence, and increased leaching of contaminants, which can stress crops and lower yields.

Current climate models do not adequately account for SWR’s impact on crop yields. As climate change progresses, higher temperatures and more extreme weather events are expected to increase the prevalence and severity of SWR, posing a significant threat to food security. Rising temperatures can induce SWR by drying out soils, while droughts and wildfires exacerbate the problem.

The study highlights that conventional and soil health management practices affect SWR differently. Practices like tillage, irrigation, fallow fields, cover cropping, and the application of amendments all play roles in managing or exacerbating SWR. Conservation tillage and no-till practices can retain soil moisture but may also increase SWR under certain conditions. Irrigation helps maintain soil moisture above critical levels to prevent SWR, while burning fields can both create and reduce SWR depending on fire intensity and soil conditions.

The researchers call for integrating SWR considerations into climate change models to more accurately predict future food security challenges. They suggest using modern biomarking spectral and chemometric analyses to determine the repellency potential of soil inputs and develop robust management strategies that enhance agroecosystem sustainability.