Hedgerow impacts on soil‐water transfer due to rainfall interception and root‐water uptake

Abstract

Abstract:Hedgerow is one of the most important rural landscapes in the world, especially in Europe. Knowledge about the hydrological role of hedgerows is useful in many fields of study, such as hydrological modelling and rural landscape management. The aim of this study was to investigate the impact of a hedgerow on rainfall distribution, soil-water potential gradient, lateral water transfer and water balance. A hillslope with a hedgerow perpendicular to the slope was monitored. To evaluate hedgerow rainfall interception, rainfall was measured (hourly, daily, and by rainfall event) both next to and up to 16 m upslope and 12 m downslope perpendicularly away from the hedgerow. The strongest correlation between rainfall next to the hedgerow and rainfall at more distant points was obtained using data measured per rainfall event. The average percentage of rainfall intercepted equalled 28% for the leafed period and 12% for the leafless period. The impact of the hedgerow on spatial rainfall distribution was related to distance from the hedgerow and rainfall amount. Annual distribution of soil-water potential showed that the hedgerow influenced it up to 9 m upslope and 6 m downslope, the area in which most of the hedgerow's roots were observed. The soil was driest at the end of summer, which delayed soil rewetting during autumn in areas surrounding the hedgerow. Annual groundwater dynamics exhibited three distinct periods due to temporal rainfall distribution and, especially at the end of summer, root-water uptake. In addition, the total potential gradient showed that unsaturated flow was directed towards the hedgerow in summer and autumn. These results indicate that at the local scale hedgerows influences (1) spatial rainfall distribution, (2) soil rewetting, and (3) groundwater recharge, often at distances well beyond the hedgerow's drip line. Consequently, the processes involved in soil-water dynamics around hedgerows should be integrated into relevant hydrological models, especially for catchments with a dense hedgerow network.

Nonstationarity of the electrical resistivity and soil moisture relationship in a heterogeneous soil system: a case study

“…The clay content of shallow and organo-mineral horizons ranged from 14.6-16.0 % in the upslope zone and exceeded 20 % in the downslope zone (Ghazavi et al, 2008). At greater depths, the endostagnic B horizon observed in the Luvic Cambisol (UP16) had a clay content of 23.3 %, but the highest clay content was observed in the Stagnic Fluvisol in the bottomland (DW12).…”

“…At greater depths, the endostagnic B horizon observed in the Luvic Cambisol (UP16) had a clay content of 23.3 %, but the highest clay content was observed in the Stagnic Fluvisol in the bottomland (DW12). It ranged from 24.7 % in the shallow epistagnic fluvic B1 horizon to 27.1 % in the endostagnic fluvic B2 horizon at depths of 0.4 to 0.9 m. At depth, the schist saprolite (C mineral horizon) had a loam-sandy-clayey texture (Table I in Ghazavi et al, 2008). We observed several coarse-particle accumulations (e.g., stones, quartz veins) in the 2-D vertical soil cross section, in particular in the upslope zone and near the ditch along the hedgerow.…”

“…Hedgerow removal due to farm enlargement is the major land use change since the Second World War. Previous studies suggest a significant impact of hedgerows on soil moisture (Caubel, 2001; and rainfall distribution (Ghazavi et al, 2008). Many studies have explored the effect of hedgerows surrounding wetlands on water fluxes and the subsequent increase in transpiration (Thomas et al, 2012) and decrease in nitrate concentration ).…”

Oat grain yield under nitrogen uses in an eucalyptus intercropping system in Subtropical Brazil

“…1d), which may have occurred as a consequence of yield reductions, most likely aggravated by lodging in positions B and C (DEISS et al, 2014a). In contrast, the rainwater interception and redistribution (GHAZAVI et al, 2008, SILES et al, 2010 by the eucalyptus could have added to the alleviation of below-ground competition promoted by nitrogen fertilization, which favored the grain yield at the highest slope elevation (i.e., positions L. Deiss et al D and E) between two adjacent tree tracks (Figure 1d). Because the trees were planted at a guideline level, the rainwater runoff intercepted by trees always favors the highest elevation of the slope between the tree tracks.…”

Rural land management impacts on catchment scale flood risk

“…There has been a 50% reduction in hedgerows since 1945 (Robinson and Sutherland, 2002), which increases the connectivity between hillslopes and the river channel. Ghazavi et al, (2008) studied the hydrological effects of hedgerows in terms of interception, soil moisture dynamics and groundwater transfer.…”