scholarly journals Stochastic estimation of the distribution of soil water repellency on the soil surface in a humid-temperate forest

2021 ◽  
Author(s):  
Masako Kajiura
Keyword(s):  
Soil Water ◽  
Temperate Forest ◽  
Estimation Error ◽  
Soil Surface ◽  
Water Repellency ◽  
Stochastic Approach ◽  
Cumulative Probability ◽  
Soil Water Repellency ◽  
Cumulative Normal Distribution ◽  
Normally Distributed

Soil water repellency (SWR) increases surface runoff and preferential flows. Thus, quantitative evaluation of SWR distribution is necessary to understand water movements. Because the variability of SWR distribution makes it difficult to measure directly, we developed a method for estimating an SWR distribution index, defined as the areal fraction of surface soil showing SWR (SWRarea). The theoretical basis of the method is as follows: (1) SWRarea is equivalent to the probability that a position on the soil surface is drier than the critical water content (CWC); SWR is present (droplets absorbed in >10 s) when the soil surface is drier than the CWC and absent when it is wetter. (2) CWC and soil moisture content (θ) are normally distributed independent variables. (3) Thus, based on probability theory, the cumulative normal distribution of θ – CWC (f(x)) can be obtained from the distributions of CWC and θ, and f(0), the cumulative probability that θ – CWC < 0, gives the SWRarea. To investigate whether the method gives reasonable results, we repeatedly measured θ at 0–5 cm depth and determined the water repellency of the soil surface at multiple points in fixed plots with different soils and topography in a humid-temperate forest. We then calculated the CWC from the observed θ–SWR relationship at each point. We tested the normality of the CWC and θ distributions and the correlation between CWC and θ. Then, we determined f(x) from the CWC and θ distributions and estimated the SWRarea on each measurement day. Although CWC and θ were both normally distributed, in many cases they were correlated. Nevertheless, the CWC–θ dependency had little effect on the estimation error, and f(x) explained 69% of the SWRarea variability. Our findings show that a stochastic approach is useful for estimating SWRarea.

Soil water repellency under dry and wet antecedent weather conditions for selected land-cover types in the coastal zone of central Portugal

Soil Research ◽  
2005 ◽  
Vol 43 (3) ◽  
pp. 297 ◽  
Author(s):  
J. J. Keizer ◽  
C. O. A. Coelho ◽  
M. J. S. Matias ◽  
C. S. P. Domingues ◽  
A. J. D. Ferreira
Keyword(s):  
Land Cover ◽  
Soil Water ◽  
Arable Land ◽  
Late Summer ◽  
Soil Surface ◽  
Water Repellency ◽  
Weather Conditions ◽  
Individual Plant ◽  
Soil Water Repellency ◽  
Land Cover Types

This paper reports on the first systematic inventory of soil water repellency in Portuguese coastal dune sand areas. Since water repellency is widely associated with certain vegetation types or individual plant species, this inventory concerned arable land as well as 6 natural and semi-natural land-cover types representative for the vegetation zonation in the study area. Since water repellency further is a feature that commonly varies through time, disappearing when soils become wet, initial sampling was carried out during late summer 2000 and later repeated, at 1 of the 2 sites per land-cover type, during early spring 2001. Water repellency was principally measured in the field using the Molarity of an Ethanol Droplet (MED) test. Under the dry summer conditions, water repellency was a widespread phenomenon at and immediately below, the soil surface and numerous significant differences in ethanol classes existed between the land-cover types. The transient nature of water repellency was confirmed by many instances of significantly lower spring than summer ethanol classes. These significant differences were in general accompanied by a significant negative correlation of the summer and spring ethanol classes with volumetric soil moisture content. The sites’ overall repellency levels under dry antecedent weather conditions were significantly correlated with their overall levels of soil organic matter.

The role of soil water repellency in overland flow generation in pine and eucalypt forest stands in coastal Portugal

Soil Research ◽  
2005 ◽  
Vol 43 (3) ◽  
pp. 337 ◽  
Author(s):  
J. J. Keizer ◽  
C. O. A. Coelho ◽  
R. A. Shakesby ◽  
C. S. P. Domingues ◽  
M. C. Malvar ◽  
...  
Keyword(s):  
Soil Water ◽  
Overland Flow ◽  
Slope Angle ◽  
Soil Surface ◽  
Water Repellency ◽  
Rainfall Simulation ◽  
Soil Water Repellency ◽  
Infiltration Capacity ◽  
Eucalypt Forest ◽  
Flow Generation

Soil water repellency is now known to occur in diverse soils in various parts of the world. One of the possible adverse effects of soil water repellency is that it can reduce infiltration capacity and hence, on sloping terrain, enhance overland flow and soil erosion. The main aim of the present work is to assess the effects of soil water repellency on surface runoff production in the inner coastal dune areas of central Portugal. This was done for a pine and a eucalypt forest stand and, within each stand, for 2 slopes with contrasting aspect and somewhat different slope angles. Overland flow was measured for 4 pairs of unbounded plots of about 5 m2 at fortnightly intervals from February to October 2001. Over the same period, soil water repellency at and immediately below the soil surface was measured next to the plots at monthly intervals. The runoff–repellency relationship was also studied by carrying out rainfall simulation experiments on 0.24-m2 plots and associated repellency measurements. The effect of soil water repellency was most clearly demonstrated by statistically significant higher runoff coefficients under strong-to-extremely than under none-to-slightly hydrophobic conditions immediately below the soil surface. Such a difference in runoff over the measurement period was, however, restricted to 2 unbounded plots, both of which were located on the eucalypt slope with a southerly aspect and the greater slope angle. At the scale of these plots, the increase in runoff coefficient due to soil water repellency is moderate, when integrated over the entire period of strong–extremely repellent conditions, but can be quite substantial for individual 2-weekly periods. With respect to the observed differences in runoff between plots, be it plots on the same slope or not, it has proved difficult to distinguish the effect of soil water repellency from that of other factors likely to affect overland flow generation.

scholarly journals Testing soil water repellency in a Sicilian area two years after a fire

2019 ◽  
Author(s):  
Vincenzo Bagarello ◽  
Giuseppe Basile ◽  
Gaetano Caltabellotta ◽  
Giuseppe Giordano ◽  
Massimo Iovino
Keyword(s):  
Soil Water ◽  
Water Drop ◽  
Soil Layer ◽  
Soil Surface ◽  
Water Repellency ◽  
Soil Conditions ◽  
Small Scale ◽  
Water Repellent ◽  
Soil Water Repellency ◽  
Mountain Area

The water drop penetration time (WDPT) technique was applied in 2018 to check persistence of soil water repellency (SWR) in a Sicilian mountain area affected by a wildfire on June 2016. A total of four sites, that were severely water repellent immediately after burning, were sampled. Depending on the site, wettable soil conditions, less SWR and maintenance of a noticeable SWR were detected two years later. At the site showing a near-constant SWR, WDPTs were particularly high in the top soil layer (0-0.03 m) and they appreciably decreased more in depth. Signs of decreasing SWR in drier soil conditions and in association with coarser soil particles were also detected at this site. High gradients of the WDPT can occur at very small vertical distances and a depth increment of approximately 0.01 m should be appropriate to capture small-scale vertical changes in SWR, especially close to the soil surface. Occurrence of SWR phenomena is easily perceivable and explainable if an inverse relationship between WDPTs and antecedent soil water content is obtained. A direct relationship between these two variables is more difficult to interpret because infiltration times that increase in wetter soil are expected according to the classical infiltration theory. A hypothesis that should be tested in the future is to verify if WDPTs that decrease in drier soil conditions signal less SWR as a consequence of a reduced biological activity of the soil. Finally, long-term monitoring projects on longevity of fire effects on SWR should be developed, even because an in depth knowledge of the involved processes is relevant for the civil protection system.

scholarly journals Post-Fire Impacts of Vegetation Burning on Soil Properties and Water Repellency in a Pine Forest, South Korea

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 708
Author(s):  
Qiwen Li ◽  
Sujung Ahn ◽  
Taehyun Kim ◽  
Sangjun Im
Keyword(s):  
Organic Carbon ◽  
Soil Properties ◽  
Total Organic Carbon ◽  
Soil Water ◽  
Soil Ph ◽  
Forest Fires ◽  
Soil Surface ◽  
Water Repellency ◽  
Burn Severity ◽  
Soil Water Repellency

Forest fires can have a direct and immediate impact on soil properties, particularly soil water repellency. This study investigated the direct impacts of the Gangneung forest fire of 2019 on soil properties and the spatial variability of soil water repellency with vegetation burn severity in the Korean red pine (Pinus densiflora Siebold and Zucc) forest of South Korea. A total of 36 soil samples were collected at depth intervals of 0–5 cm, 10–15 cm, and 20–25 cm from three burned sites, representing surface-fuel consumption (SC), foliage necrosis (FN), and crown-fuel consumption (CC), respectively. An unburned site was also used as a control. Soil properties such as soil texture, pH, bulk density, electrical conductivity (EC), total organic carbon (TOC), and cation exchange capacity (CEC) were analyzed in the laboratory. The increase in the sand fraction near the soil surface after a fire was associated with changes in silt and clay fractions. Moderate to high vegetation burn severity at the FN and CC sites caused a decrease in soil pH due to the thermal destruction of kaolinite mineral structure, but organic matter combustion on the soil surface increased soil pH at the SC site. Forest fires led to increases in total organic carbon at the FN and SC sites, owing to the external input of heat damaged foliage and burnt materials. Molarity of an ethanol droplet (MED) tests were also conducted to measure the presence and intensity of soil water repellency from different locations and soil depths. MED tests showed that vegetation burn severity was important for determining the strength of water repellency, because severely burned sites tended to have stronger water repellency of soil than slightly burned sites. Unburned soils had very hydrophilic characteristics across soil depths, but a considerably thick hydrophobic layer was found in severely burned sites. The soil water repellency tended to be stronger on steep (>30°) slopes than on gentle (<15°) slopes.

Soil water repellency in sandy soil depends on the soil drying method, incubation temperature and specific surface area

Geoderma ◽  
2021 ◽  
Vol 402 ◽  
pp. 115264
Author(s):  
Enoch V.S. Wong ◽  
Philip R. Ward ◽  
Daniel V. Murphy ◽  
Matthias Leopold ◽  
Louise Barton
Keyword(s):  
Specific Surface ◽  
Soil Water ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sandy Soil ◽  
Incubation Temperature ◽  
Water Repellency ◽  
Soil Drying ◽  
Drying Method ◽  
Soil Water Repellency

The use of visible and near-infrared spectroscopy for the analysis of soil water repellency

2014 ◽  
Vol 65 (3) ◽  
pp. 360-368 ◽  
Author(s):  
I. Kim ◽  
R. R. Pullanagari ◽  
M. Deurer ◽  
R. Singh ◽  
K. Y. Huh ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Soil Water ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Water Repellency ◽  
Soil Water Repellency

Soil water repellency persistence after recurrent forest fires on Mount Carmel, Israel

2013 ◽  
Vol 22 (4) ◽  
pp. 515 ◽  
Author(s):  
Naama Tessler ◽  
Lea Wittenberg ◽  
Noam Greenbaum
Keyword(s):  
Organic Matter ◽  
Soil Water ◽  
Forest Fires ◽  
Water Drop ◽  
Chemical Properties ◽  
Water Repellency ◽  
Mediterranean Ecosystem ◽  
Long Term Effects ◽  
Soil Water Repellency ◽  
Chemical Properties Of Soils

Variations in forest fires regime affect: (1) the natural patterns of community structure and vegetation; (2) the physico-chemical properties of soils and consequently (3) runoff, erosion and sediment yield. In recent decades the Mediterranean ecosystem of Mount Carmel, north-western Israel, is subjected to an increasing number of forest fires, thus, the objectives of the study were to evaluate the long-term effects of single and recurrent fires on soil water repellency (WR) and organic matter (OM) content. Water repellency was studied by applying water drop penetration time (WDPT) tests at sites burnt by single-fire, two fires, three fires and unburnt control sites. Water repellency in the burnt sites was significantly lower than in the unburnt control sites, and the soil maintained its wettability for more than 2 decades, whereas after recurrent fires, the rehabilitation was more complicated and protracted. The OM content was significantly lower after recurrent than after a single fire, causing a clear proportional decrease in WR. The rehabilitation of WR to natural values is highly dependent on restoration of organic matter and revegetation. Recurrent fires may cause a delay in recovery and reduced productivity of the soil for a long period.

Organic Matter Fractions Controlling Soil Water Repellency in Sandy Soils From the Doñana National Park (Southwestern Spain)

2014 ◽  
Vol 27 (5) ◽  
pp. 1413-1423 ◽  
Author(s):  
Nicasio T. Jiménez‐Morillo ◽  
José A. González‐Pérez ◽  
Antonio Jordán ◽  
Lorena M. Zavala ◽  
José María Rosa ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Water ◽  
National Park ◽  
Sandy Soils ◽  
Water Repellency ◽  
Soil Water Repellency ◽  
Doñana National Park ◽  
Organic Matter Fractions
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