scholarly journals Soil hydrophobicity: comparative study of usual determination methods

2015 ◽  
Vol 45 (2) ◽  
pp. 260-266 ◽  
Author(s):  
Eduardo Saldanha Vogelmann ◽  
José Miguel Reichert ◽  
Juliana Prevedello ◽  
Gabriel Oladele Awe ◽  
Dalvan José Reinert
Keyword(s):  
Water Drop ◽  
Soil Layer ◽  
Organic Matter Content ◽  
Soil Samples ◽  
Water Infiltration ◽  
Water Repellent ◽  
Hydrophobicity Index ◽  
Coefficients Of Variation ◽  
Soil Hydrophobicity ◽  
Penetration Time

Hydrophobic or water repellent soils slowly absorb water because of the low wett ability of the soil particles which are coated with hydrophobic organic substances. These pose significant effects on plant growth, water infiltration and retention, surface runoff and erosion. The objective of this study was to compare the performance of tension micro-infiltrometer(TMI) and the water drop penetration time (WDPT) methods in the determination of the hydrophobicity index of eighteen soils from southern Brazil. Soil samples were collected from the 0-5cm soil layer to determine particle size distribution, organic matter content, hydrophobicity index of soil aggregates and droplet penetration time of disaggregated and sieved soil samples. For the TMI method the soil samples were subjected to minor changes due to the use of macroaggregates to preserve the distribution of solid constituents in the soil. Due to the homogeneity of the soil samples the WDPT method gave smaller coefficients of variation unlike the TMI method where the soil structure is preserved. However, both methods had low coefficients of variation, and are thus effective for determining the soil hydrophobicity, especially when the log hydrophobicity index or log WDPT is >1.

scholarly journals Organic Matter Clogging Results in Undeveloped Hardpan and Soil Mineral Leakage in the Rice Terraces in the Philippine Cordilleras

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3158
Author(s):  
Tomoyo Kurozumi ◽  
Yasushi Mori ◽  
Hiroaki Somura ◽  
Milagros O-How
Keyword(s):  
Organic Matter ◽  
Soil Analysis ◽  
Influencing Factor ◽  
Soil Layer ◽  
Organic Matter Content ◽  
Matter Content ◽  
Water Infiltration ◽  
Soil Conditions ◽  
Infiltration Process ◽  
Soil Nutrition

Rice terraces in Cordillera, Philippines, a world cultural heritage site, are threatened by the risk of collapse. It is crucial to manage these rice terraces for their conservation, while simultaneously practicing traditional farming. We examined the soil environment and investigated its effects on rice terrace conservation, by focusing on the hardpan condition; infiltration process, which is related to the collapse of rice terraces; and soil nutrition conditions in these sites. Field survey and soil analysis revealed that in areas where the hardpan was not sufficiently developed and water infiltration was effectively suppressed, organic matter content was significantly high, suggesting organic matter clogging. In these rice terraces, the amounts of P, K, Ca, and Mn were significantly low, showing the mineral leaching under reductive soil conditions. Therefore, hardpan formation, rather than organic matter clogging, is essential for the suppression of infiltration and prevention of potential terrace collapse. Because hardpan formation or organic matter clogging cannot be identified from the surface of flooded rice paddies, it is difficult to identify the influencing factor. Thus, we suggest that the hard soil layer should be checked before the planting season and drainage is allowed after the cropping season in the rainy season.

The influence of surfactant and organic matter content on wetting pattern of different non-water repellent soils

Soil Research ◽  
2016 ◽  
Vol 54 (7) ◽  
pp. 880
Author(s):  
Mohammad Reza Chaichi ◽  
Marcus Turcios ◽  
Mina Rostamza
Keyword(s):  
Organic Matter ◽  
Sandy Loam ◽  
Organic Matter Content ◽  
Matter Content ◽  
Water Infiltration ◽  
Water Repellent ◽  
Ionic Surfactant ◽  
Silt Loam ◽  
Wetted Area ◽  
Wetting Pattern

Non-ionic surfactants have been well researched as a tool to ameliorate water repellent conditions. However, few studies have evaluated the risks and benefits of non-ionic surfactant applications in wettable soil. The objective of this study was to evaluate the effects of a surfactant in modifying the wetting pattern in soils of different textures and organic matter contents. The experimental treatments consisted of (1) four different soil textures including sandy, sandy loam, sandy clay loam and silt loam, (2) four different organic matter contents (0.2, 0.7, 1.2 and 1.7% by weight), and (3) irrigation water treatments with or without surfactant (IrrigAid Gold). The experiment was carried out in Plexiglas boxes with one drip emitter under the soil surface. The results demonstrated the superiority of surfactant application on increasing water distribution in the soil profile for all soil textural classes. Silt loam texture had the highest side wetted area and wetting depth 45min after the initiation of irrigation. Upward capillary water movement and top wetted area significantly decreased in the surfactant treatment across all soil textures except in sandy soil. As organic matter content increased, top wetted area decreased. These findings clarified the potential ability of surfactant in increasing water infiltration in non-repellent soil in an in vitro system.

scholarly journals Soil wetting agents influences on soil hydrophobicity : the effects and mechanisms

2017 ◽  
Author(s):  
◽  
Enzhan Song
Keyword(s):  
Microbial Community ◽  
Soil Water ◽  
Soil Microbial Community ◽  
Soil Microbiology ◽  
Wetting Agent ◽  
Water Infiltration ◽  
Water Repellent ◽  
Soil Microbial ◽  
Soil Hydrophobicity ◽  
Wetting Agents

Soil water repellency (SWR), which causes uneven water distribution in top soil, is a common problem for sandy soils, especially on sand-based growing media such as USGA (United States Golf Association) greens. The SWR is caused by wax-like organic substances coating on the surface of sand particles which repel water. Wetting agent, which are surface active agents or surfactants, have bi-affinity structure with water-loving (hydrophilic) and water-repellent (hydrophobic) groups on each end of the structure, is the primary tool for treatment of SWR. The hydrophobic end will attach wetting agent compounds with SWR coatings at the sand surface, thus facing the water-loving side towards outside and interact with surrounding water molecules. Wetting agents are developed with mainly two purposes: enhancement of water infiltration and improving water retention. More recently designed products also aim at potentially remove SWR causing organic coatings from the soil profile thus provide longer and more efficient wetting. However, previous studies conducted in turf area on wetting agents related topics often only looked at the treatment effects on turfgrass responses and overall turf performance. The objective of this dissertation study is to comprehensively investigate the direct wetting agents influences on soil hydrology (soil water movement), soil chemistry (hydrophobic organic coating removal), and soil microbiology (soil microbial community), with goal of explaining the working mechanisms of different wetting agents. Except pHAcid, most tested wetting agents mitigated SWR with either enhanced infiltration rate or reduced soil hydrophobicity. While the compounds of OARS strongly sorped into the SWR sand system and increased SWR, Matador successfully removed significant amount of non-dissolved organic materials from the SWR sand and transformed the sand to spontaneous wetting status. The soil microbial community was significantly influenced by the weather conditions, while wetting agents that enhanced infiltration (e.g. Hydro-Wet) potentially reduced soil water holding capacity and led to decreased soil microbial abundancy.

scholarly journals Persistence of water repellency in coarse-textured soils under various types of forests in NW Spain

2019 ◽  
Vol 67 (2) ◽  
pp. 129-134 ◽  
Author(s):  
Elena Benito ◽  
Eufemia Varela ◽  
María Rodríguez-Alleres
Keyword(s):  
Eucalyptus Globulus ◽  
Water Drop ◽  
Soil Layer ◽  
Water Repellency ◽  
Soil Samples ◽  
Penetration Test ◽  
Dry Period ◽  
Nw Spain ◽  
Soil Water Repellency ◽  
Very High

Abstract The primary purpose of this work was to assess the persistence of water repellency in the surface horizon of coarse-textured soils under natural Quercus robur ecosystems, and Pinus pinaster and Eucalyptus globulus plantations, in the northwest of the Iberian Peninsula. Water repellency was determined by applying the water drop penetration test (WDPT) to soil samples collected from variable depths (0–40 cm). Measurements were made on field-moist samples obtained at the end of the dry period and on samples dried at 25ºC in the air. All soils exhibited very high (severe to extreme) water repellency in the topmost soil layer (0–5 cm) but no significant differences among the three plant species studied. Extreme persistence was observed down to 20 cm in the soils under eucalyptus and down to 10 cm in those under pine. The soils under oak were those exhibiting the highest variability in water repellency and the greatest decrease in it with increasing depth (especially in relation to soils under eucalyptus). Water repellency exhibited significant positive correlation with the C content and C/N ratio of the soils. Soil water repellency was similar in the air-dried samples and field-moist samples.

Soil attributes related to water repellency and the utility of soil survey for predicting its occurrence

Soil Research ◽  
1994 ◽  
Vol 32 (5) ◽  
pp. 1109 ◽  
Author(s):  
RJ Harper ◽  
RJ Gilkes
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Water Drop ◽  
Organic Matter Content ◽  
Clay Content ◽  
Soil Surface ◽  
Water Repellency ◽  
Soil Survey ◽  
Organic Carbon Content ◽  
Penetration Time

The incidence and severity of water repellency was related to five soil class (FC I-V), based on the field texture and dry consistence of the soil surface horizons, derived from a soil survey near Jerramungup, Western Australia. Water repellency was most severe on the FC I soils (median clay content 1.5%), with 66% of samples having water repellency based on the water drop penetration time (WDPT) test >10 s. Corresponding values for the FC II and III soils (2.5%, 4.0% clay) were 37% and 20%. Water repellency did not occur on the most clayey FC IV (8.1% clay) and FC V (22.1% clay) soils. Following stratification of Ap horizon soils by 1% increments of clay content, highly significant linear relationships occurred between log [water drop penetration time (WDPT)] and log [organic carbon (OC)] for the 1-2, 2-3 and 3-4% clay classes, these respectively explaining 50, 35 and 37% of the variation in water repellency. The role of organic carbon in promoting water repellency decreases markedly with increasing clay content, with WDPT being proportional to OC4.5, OC3.9 and OC3.0 for each of these clay classes. A multivariate relationship using measures of amorphous iron, clay and organic matter explained 63% of the variation in water repellency, and this multivariate dependency provides an explanation of the poor bivariate relationships between either clay or organic carbon content and water repellency reported in previous studies. There is a strong geomorphic control of the clay content in the soil surface horizons. Given the effect that clay content has on water repellency, the susceptibility of soils to water repellency can be mapped across farms, with the actual expression of water repellency depending on soil organic matter content, and hence land use. Such discrimination will allow the prediction of water erosion hazard and identify soils requiring ameliorative treatments.

scholarly journals Water stable aggregates of Japanese Andisol as affected by hydrophobicity and drying temperature

2014 ◽  
Vol 62 (2) ◽  
pp. 97-100 ◽  
Author(s):  
D.A.L. Leelamanie ◽  
Jutaro Karube
Keyword(s):  
Contact Angle ◽  
Sessile Drop ◽  
Water Drop ◽  
Aggregate Stability ◽  
Water Repellency ◽  
Water Stability ◽  
Drying Temperature ◽  
Hydrophobic Materials ◽  
Soil Hydrophobicity ◽  
Penetration Time

Abstract Hydrophobicity is a property of soils that reduces their affinity for water, which may help impeding the pressure build-up within aggregates, and reducing aggregate disruption. The purpose of this study was to examine the relation of soil hydrophobicity and drying temperature to water stability of aggregates while preventing the floating of dry aggregates using unhydrophobized and hydrophobized surface Andisol. Soil was hydrophobized using stearic acid into different hydrophobicities. Hydrophobicity was determined using sessile drop contact angle and water drop penetration time (WDPT). Water stability of aggregates (%WSA) was determined using artificially prepared model aggregates. The %WSA increased as the contact angle and WDPT increased. Contact angle and WDPT, which provided maximum %WSA showing less than 1 s of floating, was around 100° and 5 s, respectively. Although the %WSA gradually increased with increasing contact angle and WDPT above this level, high levels of hydrophobicity initiated aggregate floating, which would cause undesirable effects of water repellency. Heating at 50°C for 5 h d-1 significantly affected %WSA and hydrophobicity in hydrophobized samples, but did not in unhydrophobized samples. The results indicate that the contact angle and wetting rate (WDPT) are closely related with the water stability of aggregates. The results further confirm that high levels of hydrophobicities induce aggregate floating, and the drying temperature has differential effects on hydrophobicity and aggregate stability depending on the hydrophobic materials present in the soil.

scholarly journals Application of minidisk infiltrometer to estimate water repellency in Mediterranean pine forest soils

2017 ◽  
Vol 65 (3) ◽  
pp. 254-263 ◽  
Author(s):  
Vincenzo Alagna ◽  
Massimo Iovino ◽  
Vincenzo Bagarello ◽  
Jorge Mataix-Solera ◽  
Ľubomír Lichner
Keyword(s):  
Water Drop ◽  
Mineral Soil ◽  
Soil Layer ◽  
Water Repellency ◽  
Water Infiltration ◽  
Pine Forests ◽  
Hydrophobic Compounds ◽  
Floor Layer ◽  
Alternative Procedures ◽  
Mediterranean Pine

AbstractAssessment of soil water repellency (SWR) was conducted in the decomposed organic floor layer (duff) and in the mineral soil layer of two Mediterranean pine forests, one in Italy and the other in Spain, by the widely-used water drop penetration time (WDPT) test and alternative indices derived from infiltration experiments carried out by the minidisk infiltrometer (MDI). In particular, the repellency index (RI) was calculated as the adjusted ratio between ethanol and water soil sorptivities whereas the water repellency cessation time (WRCT) and the specifically proposed modified repellency index (RIm) were derived from the hydrophobic and wettable stages of a single water infiltration experiment. Time evolution of SWR and vegetation cover influence was also investigated at the Italian site. All indices unanimously detected severe SWR conditions in the duff of the pine forests. The mineral subsoils in the two forests showed different wettability and the clay-loam subsoil at Ciavolo forest was hydrophobic even if characterized by organic matter (OM) content similar to the wettable soil of an adjacent glade. It was therefore assumed that the composition rather than the total amount of OM influenced SWR. The hydraulic conductivity of the duff differed by a factor of 3.8–5.8 between the two forested sites thus influencing the vertical extent of SWR. Indeed, the mineral subsoil of Javea showed wettable or weak hydrophobic conditions probably because leaching of hydrophobic compounds was slowed or prevented at all. Estimations of SWR according to the different indices were in general agreement even if some discrepancies were observed. In particular, at low hydrophobicity levels the SWR indices gathered from the MDI tests were able to signal sub-critical SWR conditions that were not detected by the traditional WDPT index. The WRCT and modified repellency index RImyielded SWR estimates in reasonable agreement with those obtained with the more cumbersome RI test and, therefore, can be proposed as alternative procedures for SWR assessment.

Soil water repellency in north-eastern Greece with adverse effects of drying on the persistence

Soil Research ◽  
2005 ◽  
Vol 43 (3) ◽  
pp. 281 ◽  
Author(s):  
Apostolos K. Ziogas ◽  
Coen J. Ritsema ◽  
Klaas Oostindie ◽  
Louis W. Dekker
Keyword(s):  
Soil Water ◽  
Water Repellency ◽  
Soil Samples ◽  
Water Infiltration ◽  
Agricultural Fields ◽  
Water Repellent ◽  
Soil Water Repellency ◽  
Kiwi Fruit ◽  
Soil Matrix ◽  
North Eastern

Many soils may be water repellent to some degree, challenging the common perception that soil water repellency is only an interesting aberration. When dry, water repellent soils resist or retard water infiltration into the soil matrix. Soil water repellency often leads to the development of unstable wetting and preferential flow paths. In the present study the persistence of water repellency was examined on samples from topsoils in Thrace, north-eastern Greece, using the Water Drop Penetration Time (WDPT) test. The soil samples were collected from agricultural fields throughout the prefectures of Xanthi and Rodopi. Six sites were selected for intensive sampling of water repellency and soil moisture content in transects. Water repellency was measured on field-moist soil samples and after drying the samples at increasing temperatures, to study the influence of drying temperature on the persistence of soil water repellency. Measurements of soil samples taken in agricultural fields under different crops, e.g. winter wheat, tobacco, clover, olive groves, kiwi fruit, and vineyards, in the area of Thrace, revealed that 45% of the locations exhibited actual water repellency during dry periods. Drying of samples from the Sostis site resulted in wettable soil, whereas drying of samples from the Mitriko site increased repellency. Therefore, water repellency should preferably be measured on samples taken in the field under dry conditions in order to reveal and determine the highest persistence of water repellency that might occur in the field.

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.

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