TY - JOUR
T1 - Humic acid, dextran, and valeric acid representing macromolecules similar to compounds prevailing in treated wastewater induce soil hydrophobicity
AU - Tolkin, Shai
AU - Chen, Yona
AU - Tarchitzky, Jorge
N1 - Publisher Copyright:
© 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
PY - 2020/10/1
Y1 - 2020/10/1
N2 - Purpose: Organic compounds originating from treated wastewater and soil texture have been reported to be the dominant factors influencing soil hydrophobicity. It is the aim of this investigation to elaborate the role of humic acid, dextran, and valeric acid, representing dissolved organic matter, polysaccharides, and fatty acids, respectively, as well as imitating their activity in inducing soil sub-critical water repellency induced by treated wastewater irrigation. Materials and methods: The relationships between three model compounds imitating fractions of dissolved organic matter commonly found in treated wastewater, soil texture in relation to water repellency, were investigated. Three types of organic molecules, five soil mixtures with different specific surface areas, and three different organic compounds, as well as a mixture of the three, were tested. Results and discussion: After 14–15 of wetting and drying cycles, low levels (sub-critical hydrophobicity) of water repellency developed in all soil mixtures were subjected to applications of several solutions of organic compounds, in comparison with a freshwater control. The highest degree of water repellency was exhibited by the soil with the lowest clay content (lowest specific surface area) and it decreased with increasing clay content (increasing specific surface area). Conclusions: The order of intensity of sub-critical water repellency levels induced by the organic compounds was consistent, yet independent of soil texture. However, soil texture exhibited large influence on soil hydrophobicity in response to the various organic chemicals. Humic acid, the closest in structure to organic matter prevailing in treated wastewater, exhibited the largest effect in inducing soil hydrophobicity.
AB - Purpose: Organic compounds originating from treated wastewater and soil texture have been reported to be the dominant factors influencing soil hydrophobicity. It is the aim of this investigation to elaborate the role of humic acid, dextran, and valeric acid, representing dissolved organic matter, polysaccharides, and fatty acids, respectively, as well as imitating their activity in inducing soil sub-critical water repellency induced by treated wastewater irrigation. Materials and methods: The relationships between three model compounds imitating fractions of dissolved organic matter commonly found in treated wastewater, soil texture in relation to water repellency, were investigated. Three types of organic molecules, five soil mixtures with different specific surface areas, and three different organic compounds, as well as a mixture of the three, were tested. Results and discussion: After 14–15 of wetting and drying cycles, low levels (sub-critical hydrophobicity) of water repellency developed in all soil mixtures were subjected to applications of several solutions of organic compounds, in comparison with a freshwater control. The highest degree of water repellency was exhibited by the soil with the lowest clay content (lowest specific surface area) and it decreased with increasing clay content (increasing specific surface area). Conclusions: The order of intensity of sub-critical water repellency levels induced by the organic compounds was consistent, yet independent of soil texture. However, soil texture exhibited large influence on soil hydrophobicity in response to the various organic chemicals. Humic acid, the closest in structure to organic matter prevailing in treated wastewater, exhibited the largest effect in inducing soil hydrophobicity.
KW - Humic acid
KW - Polysaccharides
KW - Soil wettability
KW - Water drop penetration time (WDPT)
UR - http://www.scopus.com/inward/record.url?scp=85085984599&partnerID=8YFLogxK
U2 - 10.1007/s11368-020-02687-z
DO - 10.1007/s11368-020-02687-z
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AN - SCOPUS:85085984599
SN - 1439-0108
VL - 20
SP - 3548
EP - 3556
JO - Journal of Soils and Sediments
JF - Journal of Soils and Sediments
IS - 10
ER -