Impact of climate, soil properties and grassland cover on soil water repellency

Renáta Sándor,Massimo Iovino,Lubomir Lichner,Vincenzo Alagna,Daniel Forster,Mariecia Fraser,Jozef Kollár,Peter Šurda,Viliam Nagy,Anita Szabó,Nándor Fodor

doi:10.1016/j.geoderma.2020.114780

Abstract

Numerous soil water repellency (SWR) studies have investigated the possible causes of this temporal phenomenon, yet there remains a lack of knowledge on the order of importance of the main driving forces of SWR in the context of changing environmental conditions under grassland ecosystems. To study the separate and combined effects of soil texture, climate, and grassland cover type on inducing or altering SWR, four sites from different climatic and soil regions were selected: Ciavolo (CI, IT), Csólyospálos (CSP, HU), Pwllpeiran (PW, UK), Sekule (SE, SK). The investigated parameters were the extent (determined by repellency indices RI, RIc and RIm) and persistence (determined by water drop penetration time (WDPT) and water repellency cessation time, WRCT) of SWR, as well as field water (Sw) and ethanol (Se) sorptivity, water sorptivity of hydrophobic soil state (Swh) water sorptivity of nearly wettable soil state (Sww) and field hydraulic conductivity (K). Our findings showed an area of land has a greater likelihood of being water repellent if it has a sandy soil texture and/or a high frequency of prolonged drought events. Water infiltration was positively correlated with all the sorptivities (r = 0.32–0.88), but was mostly negatively correlated with RI (r = – 0.54 at CI), WDPT (r = – 0.47 at CI) and WRCT (r = – 0.58 at CI). The importance of natural and synanthropized vegetation covers with regards to SWR was not coherent; moving to regions having coarser texture or moving to drier climatic zones led to higher risk of SWR conditions. Climate change has been predicted to lead to more frequent extreme weather events and prolonged dry periods across Europe, which will most likely increase the extent of SWR-affected areas and increase the role of SWR in water management of grassland ecosystems. Therefore, there is a need to determine SWR risk zones to prevent decreases in soil moisture content, soil fertility, carbon and nitrogen sink potentials, as well as biomass production of the related agro-ecosystems.

Highlights

More than one fifth (20.7%) of EU-28′s area is covered by temperate grasslands (EUROSTAT, 2015)
Our findings showed an area of land has a greater likelihood of being water repellent if it has a sandy soil texture and/or a high frequency of prolonged drought events
Climate change has been predicted to lead to more frequent extreme weather events and prolonged dry periods across Europe, which will most likely increase the extent of soil water repellency (SWR)-affected areas and increase the role of SWR in water management of grassland ecosystems

Summary

Introduction

More than one fifth (20.7%) of EU-28′s area is covered by temperate grasslands (EUROSTAT, 2015) These grasslands are characterized by considerable plant diversity depending on environmental conditions, management practices (grazing, mowing) and land use intensity (Fischer et al, 2015). Vegetation can have beneficial effects on surface hydrologic properties, including increasing infiltration capacity and erosion control (Moreno-de Las Heras et al, 2009). Mechanisms associated with these effects include soil organic matter accumulation and soil aggregation, the prevention of soil crusting, development of sub-surface channels in association with plant rooting (Alaoui et al, 2011; Beven and Germann, 2013; Clark and Zipper, 2016).

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