Synergistic effects of water repellency and macropore flow on the hydraulic conductivity of a burned forest soil, south-east Australia

AbstractNumerous recent laboratory studies have shown that vegetation can influence soil water flow by inducing very low levels of water repellency. In this study we extended on this previous research by developing a field-based test using a miniature infiltrometer to assess low levels of water repellency from physically based measurements of liquid flow in soil. The field-based test was verified through a simple laboratory experiment and then applied to determine the impact of vegetation and antecedent soil water content. The soil hydraulic properties determined were hydraulic conductivity, sorptivity, as well as the persistence and index of water repellency. Tests were conducted following a dry spell and wet spell on (1) forest soil (0 cm depth), (2) glade soil (0 cm depth) and (3) glade soil (50 cm depth). It was found that both the persistence and index of water repellency, R, decreased in the order as follows: forest soil > glade soil (0 cm) > glade soil (50 cm) for both dry and wet spell. The range of values of R was 0.28 (wettable) to 360 (highly water repellent), which affected hydraulic conductivity k r(−2 cm). R increased and hence k r(−2 cm) decreased in the order: forest soil < glade soil (0 cm) < glade soil (50 cm) for both the dry and wet spell. There were clear interactions between vegetation and changes to water flow caused by presence of repellency.

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The impact of vegetation on hydraulic conductivity of sandy soil

Soil and Water Research ◽

10.17221/2115-swr ◽

2008 ◽

Vol 2 (No. 2) ◽

pp. 59-66 ◽

Cited By ~ 10

Author(s):

L. Lichner ◽

T. Orfánus ◽

K. Novákova ◽

M. Šír ◽

M. Tesař

Keyword(s):

Hydraulic Conductivity ◽

Forest Soil ◽

Sandy Soil ◽

Preferential Flow ◽

Water Drop ◽

Water Repellency ◽

Forest Site ◽

Meadow Soil ◽

Capillary Suction ◽

The Impact

The objective of this study was to assess the impact of vegetation on the hydraulic conductivity of sandy soil at the locality Mláky II at Sekule (southwest Slovakia). The measurements were taken on the surface of a meadow (Meadow site), a 30-year old Scots pine (Pinus sylvestris) forest (Forest site) and a glade (Glade site). In the glade, the measurements were also taken in the depth of 50 cm (Pure sand) to reduce the influence of vegetation on the soil properties. It was found that the unsaturated hydraulic conductivity kr(−2 cm) as reduced due to the soil water repellency increased in the same order: Forest soil < Glade soil ≈ Meadow soil < Pure sand, similarly as decreased the water drop penetration time tp: Forest soil > Glade soil ≈ Meadow soil > Pure sand, which could refer to an inverse proportionality between the capillary suction and hydrophobic coating of the soil particles. The saturated hydraulic conductivity Ks increased in the following order: Meadow soil < Glade soil ≈ Forest soil < Pure sand; more than two-times higher Ks at both the Forest and Glade sites than that at the Meadow site could be the result of both the patchy growth of vegetation with some areas of bare soil at the Glade site and the macropores (dead roots) in more homogeneous humic top-layer at the Forest site. The share Br of flux through the pores with radii r longer than approximately 0.5 mm decreased in the order: Forest soil » Meadow soil > Glade soil » Pure sand, revealing the prevalence of preferential flow through macropores (dead roots) in the Forest site and a negligible share of macropores in the Pure sand.

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Peculiarities of Infiltration Measurements in Water-Repellent Forest Soil

Forests ◽

10.3390/f12040472 ◽

2021 ◽

Vol 12 (4) ◽

pp. 472

Author(s):

Tomáš Orfánus ◽

Anton Zvala ◽

Malvína Čierniková ◽

Dagmar Stojkovová ◽

Viliam Nagy ◽

...

Keyword(s):

Hydraulic Conductivity ◽

Forest Soil ◽

Forest Floor ◽

Water Repellency ◽

Water Infiltration ◽

Water Repellent ◽

Runoff Generation ◽

Field Methods ◽

Single Ring ◽

Guelph Permeameter

The paper deals with measurements of water infiltration carried out on a well-developed forest floor formed by needle-leaf litter of Norway spruce. Three field methods (tension disk permeameter, single-ring infiltrometer and Guelph permeameter) were used to determine the soil hydraulic conductivity. The results were strongly influenced by the water repellency at the interface between the O- and A-horizons. This interface was severely water repellent during the hot and dry summer season, regardless of the generally humid mountain climate of the High Tatras foothill. The single-ring method paradoxically provided lower hydraulic conductivity (3.2 × 10−4 ± 1.3 × 10−4) compared to the tension disk permeameter (8.5 × 10−4 ± 3.3 × 10−4) due to the presence of the water-repellent O/A-interface. This effect was also observed with the Guelph permeameter method, which gave the lowest value (5.6 × 10−5 ± 4.3 × 10−5). Abrupt retardation of infiltration on the water-repellent interface may generate shallow subsurface runoff (as was proved by the irrigation experiment) or litter splash during extreme rainfall events and promote water flow to deeper soil horizons through preferential pathways. The observed effects of the forest floor on rainfall infiltration will depend on the seasonal variability of soil water repellency. Although the forest floor is a source of hydrophobic substances that cause water repellency at the O/A-interface and can trigger runoff generation, at the same time its cohesive duff layer protects the forest soil from erosion.

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Pines influence hydrophysical parameters and water flow in a sandy soil

Biologia ◽

10.2478/s11756-013-0254-7 ◽

2013 ◽

Vol 68 (6) ◽

Cited By ~ 12

Author(s):

Ľubomír Lichner ◽

Jozef Capuliak ◽

Natalia Zhukova ◽

Ladislav Holko ◽

Henryk Czachor ◽

...

Keyword(s):

Hydraulic Conductivity ◽

Forest Soil ◽

Soil Water ◽

Water Flow ◽

Sandy Soil ◽

Preferential Flow ◽

Water Repellency ◽

Water Repellent ◽

Wetting Front ◽

Soil Water Repellency

AbstractPines, used for sand dune stabilization, can influence the hydrophysical parameters and water flow in an aeolian sandy soil considerably, mainly due to soil water repellency. Two sites, separated by distance of about 20 m, formed the basis of our study. A control soil (“Pure sand“) with limited impact of vegetation or organic matter was formed at 50 cm depth beneath a forest glade area. This was compared to a “Forest soil” in a 30-year old Scots pine (Pinus sylvestris) forest. Most of the hydrophysical parameters were substantially different between the two soil surfaces. The forest soil was substantially more water repellent and had two-times the degree of preferential flow compared to pure sand. Water and ethanol sorptivities, hydraulic conductivity, and saturated hydraulic conductivity were 1%, 84%, 2% and 26% those of the pure sand, respectively. The change in soil hydrophysical parameters due to soil water repellency resulted in preferential flow in the forest soil, emerging during a simulated heavy rain following a long hot, dry period. The wetting front established in pure sand exhibited a form typical of that for stable flow. Such a shape of the wetting front can be expected in the forest soil in spring, when soil water repellency is alleviated substantially.

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Influence of forest stand age on soil water repellency and hydraulic conductivity in the Mediterranean environment

The Science of The Total Environment ◽

10.1016/j.scitotenv.2020.142006 ◽

2021 ◽

Vol 753 ◽

pp. 142006 ◽

Cited By ~ 1

Author(s):

Demetrio Antonio Zema ◽

Pedro Antonio Plaza-Alvarez ◽

Xiangzhou Xu ◽

Bruno Gianmarco Carra ◽

Manuel Esteban Lucas-Borja

Keyword(s):

Hydraulic Conductivity ◽

Soil Water ◽

Water Repellency ◽

Forest Stand ◽

Stand Age ◽

Mediterranean Environment ◽

Soil Water Repellency ◽

The Mediterranean

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Determination of Spatial and Temporal Variability of Soil Hydraulic Conductivity for Urban Runoff Modelling

Water ◽

10.3390/w11050941 ◽

2019 ◽

Vol 11 (5) ◽

pp. 941 ◽

Cited By ~ 3

Author(s):

Matej Radinja ◽

Ines Vidmar ◽

Nataša Atanasova ◽

Matjaž Mikoš ◽

Mojca Šraj

Keyword(s):

Hydraulic Conductivity ◽

Temporal Variability ◽

Water Repellency ◽

Infiltration Rate ◽

Control Measures ◽

Soil Conditions ◽

Spatial And Temporal Variability ◽

Soil Hydraulic Conductivity ◽

Soil Hydraulic

Soil hydraulic conductivity has a direct influence on infiltration rate, which is of great importance for modelling and design of surface runoff and stormwater control measures. In this study, three measuring techniques for determination of soil hydraulic conductivity were compared in an urban catchment in Ljubljana, Slovenia. Double ring (DRI) and dual head infiltrometer (DHI) were applied to measure saturated hydraulic conductivity (Ks) and mini disk infiltrometer (MDI) was applied to measure unsaturated hydraulic conductivity (K), which was recalculated in Ks in order to compare the results. Results showed significant differences between investigated techniques, namely DHI showed 6.8 times higher values of Ks in comparison to DRI. On the other hand, Ks values obtained by MDI and DRI exhibited the lowest difference. MDI measurements in 12 locations of the small plot pointed to the spatial variability of K ranging between 73%–89% as well as to temporal variability within a single location of 27%–99%. Additionally, a reduction of K caused by the effect of drought-induced water repellency was observed. Moreover, results indicate that hydrological models could be enhanced using different scenarios by employing a range of K values based on soil conditions.

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Effects of heating on some soil physical properties related to its hydrological behaviour in two north-western Spanish soils

International Journal of Wildland Fire ◽

10.1071/wf03068 ◽

2004 ◽

Vol 13 (2) ◽

pp. 195 ◽

Cited By ~ 70

Author(s):

R. García-Corona ◽

E. Benito ◽

E. de Blas ◽

M. E. Varela

Keyword(s):

Organic Matter ◽

Hydraulic Conductivity ◽

Physical Properties ◽

Size Distribution ◽

Aggregate Stability ◽

Aggregate Size ◽

Total Porosity ◽

Water Repellency ◽

Aggregate Size Distribution ◽

Distribution Water

Two forest soils rich in organic matter but differing in texture (sandy loam and silty loam) were heated under controlled laboratory conditions in order to examine the consequences of the heating effect that accompanies the passage of a fire on the physical properties of soil. Three samples of both soils were heated for 30 min in a muffle furnace at temperatures of 25, 170, 220, 380 and 460°C. At each temperature, the following parameters were determined: dry aggregate size distribution, water aggregate stability, total porosity, pore size distribution, water repellency and hydraulic conductivity. Heating the soils at 170 and 220°C caused no significant changes in aggregate size distribution or total porosity but increased water aggregate stability and the volume of pores 0.2–30 μm. Also, increased water repellency and strongly decreased the hydraulic conductivity. All parameters underwent much more dramatic changes at 380 and 460°C that can be ascribed to the combustion of organic matter. At such temperatures, water repellency was destroyed and the low hydraulic conductivity can be attributed to the aggregate breakdown observed under dry and wet conditions.

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Two new species of nematode-trapping fungi (Dactylellina, Orbiliaceae) from burned forest in Yunnan, China

Phytotaxa ◽

10.11646/phytotaxa.452.1.6 ◽

2020 ◽

Vol 452 (1) ◽

pp. 65-74

Author(s):

FA ZHANG ◽

XIN-JUAN ZHOU ◽

JUTAMART MONKAI ◽

FEI-TENG LI ◽

SHUO-RAN LIU ◽

...

Keyword(s):

Phylogenetic Analysis ◽

New Species ◽

Genetic Differentiation ◽

Forest Soil ◽

Yunnan Province ◽

Species Cluster ◽

Two New Species ◽

Burned Forest

Two new Dactylellina (nematode-trapping fungi) species, D. yushanensis and D. cangshanensis from the burned forest soil in Cangshan Mountain, Yunnan Province, China are introduced in this paper based on morphology and phylogenetic analysis. Their descriptions and illustrations are provided. Dactylellina yushanensis is characterized by its geniculate branched conidiophore, two types conidia and fusiform, clavate or drop-shaped microconidia grown in conidiophore or produced by macroconidia with micro-cycle conidiation pathway. Dactylellina cangshanensis is characterized by its fusiform, spindle-shaped, clavate or drop-shaped conidia with 2-4-septate. Phylogenetic analysis based on combined ITS, EF1-α and RPB2 sequence showed that these two species cluster together with D. ellipsospora with obvious genetic differentiation.

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New Diagrams to Evaluate Soil Pore Radius Distribution and Saturated Hydraulic Conductivity of Forest Soil

Journal of Forest Research ◽

10.1007/bf02348476 ◽

1997 ◽

Vol 2 (2) ◽

pp. 95-101 ◽

Cited By ~ 14

Author(s):

Ken'ichirou Kosugi

Keyword(s):

Hydraulic Conductivity ◽

Forest Soil ◽

Pore Radius ◽

Saturated Hydraulic Conductivity ◽

Pore Radius Distribution

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Extension of the Gardner exponential equation to represent the hydraulic conductivity curve

Journal of Hydrology and Hydromechanics ◽

10.2478/johh-2019-0015 ◽

2019 ◽

Vol 67 (4) ◽

pp. 359-371

Author(s):

Theophilo B. Ottoni Filho ◽

Marlon G. Lopes Alvarez ◽

Marta V. Ottoni ◽

Arthur Bernardo Barbosa Dib Amorim

Keyword(s):

Hydraulic Conductivity ◽

Degrees Of Freedom ◽

Goodness Of Fit ◽

Exponential Model ◽

Capillary Length ◽

Macropore Flow ◽

Exponential Equation ◽

Van Genuchten Model ◽

Conductivity Curve ◽

Two Parameter

Abstract The relative hydraulic conductivity curve Kr(h) = K/Ks is a key variable in soil modeling. This study proposes a model to represent Kr(h), the so-called Gardner dual (GD) model, which extends the classical Gardner exponential model to h values greater than ho, the suction value at the inflection point of the Kr(h) curve in the log-log scale. The goodness of fit of GD using experimental data from UNSODA was compared to that of the MVG [two-parameter (Kro, L) Mualem-van Genuchten] model and a corresponding modified MVG model (MVGm). In 77 soils without evidence of macropore flow, GD reduced the RMSE errors by 64% (0.525 to 0.191) and 29% (0.269 to 0.193) in relation to MVG and MVGm, respectively. In the remaining 76 soils, GD generally was less accurate than MVG and MVGm, since most of these soils presented evidence of macropore flow (dual permeability). GD has three parameters and two degrees of freedom, like MVG. Two of them allow the calculation of the macroscopic capillary length, a parameter from the infiltration literature. The three parameters are highly dependent on the Kr(h) data measurement in a short wet suction range around ho, which is an experimental advantage.

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