The impact of heating on the hydraulic properties of soils sampled under different plant cover

Biologia ◽  
2009 ◽  
Vol 64 (3) ◽  
Author(s):  
Viliam Novák ◽  
Ľubomír Lichner ◽  
Bin Zhang ◽  
Karol Kňava

AbstractThe impact of heating on the peristence of water repellency, saturated hydraulic conductivity, and water retention characteristics was examined on soils from both forest and meadow sites in southwest Slovakia shortly after a wet spell. The top 5 cm of meadow soils had an initial water drop penetration time WDPT at 20°C of 457 s, whereas WDPT in the pine forest was 315 s for the top 5 cm and 982 s if only the top 1 cm was measured. Heating soils at selected temperatures of 50, 100, 150, 200, 250 and 300°C caused a marked drop in water drop penetration time WDPT from the initial value at 20°C. However, samples collected in different years and following an imposed cycle of wetting and drying showed much different trends, with WDPT sometimes initially increasing with temperature, followed by a drop after 200–300°C. The impact of heating temperature on the saturated hydraulic conductivity of soil was small. It was found for both the drying and wetting branches of soil water retention curves that an increase in soil water repellency resulted in a drop in soil water content at the same matric potential. The persistence of soil water repellency was strongly influenced by both the sampling site and time of sampling, as it was characterized by the results of WDPT tests.

2014 ◽  
Vol 2 ◽  
Author(s):  
Alexis Hernández ◽  
Natalia Rodríguez ◽  
Marcelino del Arco ◽  
Carmen Dolores Arbelo ◽  
Jesús Notario del Pino ◽  
...  

Forest fires modify the soil environment, often triggering severe soil degradation. In this paper, we studied the impact of a large northern Tenerife Canariy pine forest wildfire on a set of relevant soil properties, focusing on their evolution in time and relationship with soil water repellency. To do this, soils were sampled at four sites (burned and non-burned) and several soil physical and chemical parameters were measured. The results show significant variations for soil pH, electric conductivity (CE<sub>1:5</sub>), and NH<sub>4</sub><sup>+</sup>-N between burned and non-burned samples, whereas non-significant increases were found in burned soils for oxidizable carbon (C<sub>ox</sub>), total nitrogen (N<sub>tot</sub>) , Ca<sup>2+</sup>, Mg<sup>2+</sup>, Na<sup>+</sup> and K<sup>+</sup>, and soil hydrophobicity. The differences caused by the fire were no longer evident one year later. Furthermore, in one sampling site (Vitric Leptosols under low pine forest with a mixed heath/beech tree understory) a wide variation in the content of C<sub>ox</sub> and N<sub>tot</sub> and high water repellency was observed relative to the other sites. These differences can be attributed to the composition of the understory vegetation. Significant correlations between soil hydrophobicity with CE<sub>1:5</sub>, aggregate stability and the contents of C<sub>ox</sub>, N<sub>tot</sub>, NH<sub>4</sub><sup>+</sup>-N, Ca<sup>2+</sup>, Mg<sup>2+</sup>, Na<sup>+</sup> and K<sup>+</sup> were found.


Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2322 ◽  
Author(s):  
Mohamed Bayad ◽  
Henry Wai Chau ◽  
Stephen Trolove ◽  
Jim Moir ◽  
Leo Condron ◽  
...  

In this work, we modelled the response of soil water repellency (SWR) persistence to the decrease in moisture in drying soils, and we explored the implication of soil particle size distribution and specific surface area on the SWR severity and persistence. A new equation for the relationship between SWR persistence and soil moisture (θ) is described in this paper. The persistence of SWR was measured on ten different hydrophobic soils using water drop penetration time (WDPT) at decreasing levels of gravimetric water content. The actual repellency persistence showed a sigmoidal response to soil moisture decrease, where Ra(θ)=Rp/1+eδ(θ−θc). The suggested equation enables one to model the actual SWR persistence (Ra) using θ, the potential repellency (Rp) and two characteristic parameters related to the shape of the response curve. The two parameters are the critical soil moisture θc, where the Ra increase rate reaches its maximum, and the parameter δ affecting the steepness of the curve at the inflexion point of the sigmoidal curve. Data shows that both soil carbon and texture are controlling the potential SWR in New Zealand pastures.


2013 ◽  
Vol 22 (4) ◽  
pp. 515 ◽  
Author(s):  
Naama Tessler ◽  
Lea Wittenberg ◽  
Noam Greenbaum

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.


2008 ◽  
Vol 3 (Special Issue No. 1) ◽  
pp. S155-S164 ◽  
Author(s):  
N.A Wahl

Soil water repellency has important consequences for ecological and hydrological properties of soils and usually retards infiltration capacity and induces preferential flow. This phenomenon has been known to occur on a wide range of sites under a variety of climatic conditions. The objective of this study was to investigate and characterize soil water repellency on forest sites with identical substrate and climatic conditions, differing in tree age and species. In the Vester Torup Klitplantage, an area comprising a conifer dominated forest plantation stocking on sandy deposits in a coastal setting near the Jammer Bay in north-western Jutland/Denmark, four different forest plots were investigated for water repellency effects four times in 2005. To measure soil water repellency, the water drop penetration time test and the critical surface tension test were carried out. Both tests revealed a seasonal variability in water repellency, exhibiting the highest water repellency for the upper 10 cm of the soil during the summer months, whereas the variability between the different plots seems to be less significant. There was no coherence between humus forms, thickness of litter layer and water repellency.


2021 ◽  
Vol 753 ◽  
pp. 142006 ◽  
Author(s):  
Demetrio Antonio Zema ◽  
Pedro Antonio Plaza-Alvarez ◽  
Xiangzhou Xu ◽  
Bruno Gianmarco Carra ◽  
Manuel Esteban Lucas-Borja

2020 ◽  
Author(s):  
Peter Surda ◽  
Lubomir Lichner ◽  
Viliam Nagy

&lt;p&gt;Abandonment of agricultural lands in recent decades is occurring mainly in Europe, North America and Oceania, and changing the fate of landscapes as the ecosystem recovers during fallow stage. The objective of this study was to find the impact of secondary succession in abandoned fields on some parameters of acidic sandy soils in the Borsk&amp;#225; n&amp;#237;&amp;#382;ina lowland (southwestern Slovakia). We investigated soil chemical (pH and soil organic carbon content), hydrophysical (water sorptivity, and hydraulic conductivity), and water repellency (water drop penetration time, water repellency cessation time, repellency index, and modified repellency index) parameters, as well as the ethanol sorptivity of the studied soils. Both the hydrophysical and chemical parameters decreased significantly during abandonment of the three investigated agricultural fields. On the other hand, the water repellency parameters increased significantly, but the ethanol sorptivity did not change during abandonment. As the ethanol sorptivity depends mainly on soil pore size, the last finding could mean that the pore size of acidic sandy soils did not change during succession.&lt;/p&gt;


Geoderma ◽  
2014 ◽  
Vol 221-222 ◽  
pp. 121-130 ◽  
Author(s):  
Paramsothy Jeyakumar ◽  
Karin Müller ◽  
Markus Deurer ◽  
Carlo van den Dijssel ◽  
Karen Mason ◽  
...  

HortScience ◽  
2014 ◽  
Vol 49 (5) ◽  
pp. 662-666
Author(s):  
Lusheng Zeng ◽  
Jiayang Liu ◽  
Robert N. Carrow ◽  
Paul L. Raymer ◽  
Qingguo Huang

Organic coatings on sand particles can cause soil water repellency (SWR) where a soil does not spontaneously wet; this leads to challenges in water management and crop production. In laboratory studies, we evaluated a novel approach using direct application of 10 enzymes at three (low, medium, high) dosages to remediate SWR on two sand turfgrass soils in a 3-day incubation study and a second study at high dosage with 1-day incubation. A soil:solution ratio of 1:1 (10 g soil and 10 mL solution) was used and a deionized water control included. For Soil 7, a very strongly hydrophobic soil from a localized dry spot turfgrass area with a water drop penetration time (WDPT) of 7440 seconds (untreated) and 332 to 338 seconds (water-treated), the high dosage rates of laccase, chitinase, and protease at 1 and 3 days incubation resulted in WDPT of less than 60 seconds (i.e., hydrophilic soil). Pectinase exhibited similar results only in the 3-day incubation study. On the strongly hydrophobic Soil 21 (WDPT of 655 seconds untreated; 94 to 133 water-treated) from the dry area of a fairy ring-affected area on a turfgrass site, high dosages of chitinase, laccase, pectinase, and protease reduced WDPT to less than 60 seconds in both studies; and medium dosage rates were also effective for all but protease in the 3-day incubation study. Each of the four most effective enzymes for reducing WDPT, noted previously, demonstrated a significant exponential or logarithmic relationship between decreasing WDPT and increasing enzyme dosage. Further studies in field situations will be required to determine enzyme effectiveness on SWR and water management.


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