The contact angle of wetting as an integral indicator of physical-chemical properties of Сhernozems of Kamennaya Steppe

The sessile drop method was used to measure the contact angle of wetting (CA) of ordinary Chernozem from the fields of the Kamennaya Steppe agrolandscape used in various ways. The treatments differ in the intensity of tillage operations (protected mowed steppe, arable land after moldboard plowing), the use of mineral fertilizers and their aftereffect, as well as changes in soil properties under the influence of irrigation. At the same time, the total organic carbon content, C/N ratio, specific surface area, and rheological parameters were determined for the physical and chemical characteristics of soils. The results of the study showed that the hydrophilic-hydrophobic properties of the surface of the solid phase of soils, which largely determine the main structure-forming properties of soils, can be characterized by the value of the wetting edge angle. The CA of the studied soil samples varies from 32 degrees (highest wettability) to 45 degrees (lowest wettability). The lowest wettability is due to the increased content of hydrophobic compounds in the organic matter of soils and is characterized by the highest CA and is typical for native, untreated soil of the mowed steppe, which differs from other studied variants of the experiment in all explored physical and chemical parameters. Moldboard plowing as well as fallowing lead to changes in the physical and chemical properties of the soil and the qualitative composition of organic matter in the direction of their deterioration and a decrease in the CA. The use of mineral fertilizers contributes to the increase in the studied indicator mainly due to changes in plant productivity, in particular, the differences in CA are due to the impact of root secretions and plant residues on the soil properties. For the studied soils, the CA changes in the following series: mowed steppe > arable land with the mineral fertilizers application > arable land undergone the aftereffect of fertilizers. Correlation analysis revealed the relationship of CA with organic carbon content, specific surface area, and rheological characteristics of Chernozems. Thus, CA can serve as an integral indicator of changes in the physical and chemical properties of soils, their degradation changes under the conditions of different agricultural load. The method used in this research for determining CA requires a smaller amount of sample compared to rheological methods and is generally more informative than determining the content of organic matter.

1. Jiménez J.J., Lorenz K., Lal R., Organic carbon and nitrogen in soil particle-size aggregates under dry tropical forests from Guanacaste, Costa Rica – implications for within-site soil organic carbon stabilization, Catena, 2011, Vol. 86, Iss. 3, pp. 178–191.

2. Adamson A., Abidor I.G., Deryagin B.V., Fizicheskaya khimiya poverkhnostei (Physical chemistry of surfaces), Moscow: Mir, 1979, 568 p.

3. Kholodov V.A., Yaroslavtseva N.V., Yashin M.A., Frid A.S., Lazarev V.I., Tyugai Z.N., Milanovskiy E.Y., Contact angles of wetting and water stability of soil structure, Eurasian Soil Science, 2015, Vol. 48, No. 6, pp. 600–607.

4. Aderikhin P.G., Bogatyreva Z.S., Vozdeistvie zashchitnykh lesnykh nasazhdenii na soderzhanie i sostav organicheskogo veshchestva obyknovennykh chernozemov Kamennoi Stepi (The impact of protective forest stands on the content and composition of the organic matter of ordinary chernozems of the Stone Steppe), Pochvovedenie, 1974, No. 5, pp. 43–53.

5. Kleber M., Sollins P.,·Sutton R., A conceptual model of organo-mineral interactions in soils: self-assembly of organic molecular fragments into zonal structures on mineral surfaces, Biogeochemistry, 2007, Vol. 85, No. 1, pp. 9–24.

6. Arinushkina E.V., Rukovodstvo po khimicheskomu analizu pochv (Chemical soil analysis guide), Moscow: MGU, 1970, 487 p.

7. Kraemer F.B., Hallett P.D., Morras H., Garibaldi L., Cosentino D., Duval M., Galantini J., Soil stabilisation by water repellency under no-till management for soils with contrasting mineralogy and carbon quality, Geoderma, 2019, No. 355, p. 113902.

8. Bespalov V.A., Cheverdin Yu.I., Titova T.V., Transformatsiya pochvennogo pogloshchayushchego kompleksa chernozemnykh pochv kamennoi stepi pri dlitel'nom postmeliorativnom vozdeistvii (Transformation of the soil absorbing complex of chernozem soils of the stone steppe under prolonged post-reclamation impact), Agrofizika, 2018, No. 4, pp. 9–16.

9. Lamparter A., Bachmann J., Woche S.K., Determination of Small-Scale Spatial Heterogeneity of Water Repellency in Sandy Soils, Soil Science Society of America Journal, 2010, Vol. 74, Iss. 6, pp. 2010–2012.

10. Vityaz' P.A., Sheleg V.K., Kaptsevich V.M., Metod opredeleniya kraevogo ugla smachivaniya v poristykh poroshkovykh materialakh (A method for determining the contact angle in porous powder materials), Poroshkovaya metallurgiya, 1986, No. 4, pp. 52–55.

11. Lilliefors H.W., On the Kolmogorov-Smirnov test for normality with mean and variance unknown, Journal of the American statistical Association, 1967, Vol. 62, Iss. 318, pp. 399–402.

12. Voronin A.A., Poverkhnostnye yavleniya v pochvakh i napravlennoe izmenenie svoistv pochv (Surface phenomena in soils and a directed change in soil properties), Nauchnye doklady Vysshei shkoly, biologicheskie nauki, 1975, No. 12, pp. 7–15.

13. Liu Z., Yu X., Wan L., Capillary rise method for the measurement of the contact angle of soils, Acta Geotechnica, 2016, Vol. 11, Iss. 1, pp. 21–35.

14. Gorbunova N.S., Kulikova E.V., Izmenenie fizicheskikh i fiziko-khimicheskikh svoistv chernozema vyshchelochennogo pod vliyaniem dozhdeval'nogo orosheniya v usloviyakh proizvodstvennogo ispol'zovaniya pochv sveklovichnogo sevooborota (Change in the physical and physico-chemical properties of leached chernozem under the influence of sprinkling irrigation in conditions of industrial use of beet crop rotation soils), Vestnik Voronezhskogo gosudarstvennogo universiteta. Seriya: Khimiya. Biologiya. Farmatsiya, 2017, No. 3, pp. 47–52.

15. Markgraf W., Horn R., Peth S., An approach to rheometry in soil mechanics–Structural changes in bentonite, clayey and silty soils, Soil Tillage Res., 2006, Vol. 91, pp. 1–14.

16. Egorov V.V., Ivanova E.N., Fridland V.M., Rozov N.I., Klassifikatsiya i diagnostika pochv SSSR (Classification and soil diagnostics of the USSR), Moscow: Kolos, 1977, 221 p.

17. Markgraf W., Watts C.W., Whalley W.R., Hrkac T., Horn R., Influence of organic matter on rheological properties of soil, Applied Clay Science, 2012, Vol. 64, pp. 25–33.

18. Zborishchuk Yu.N., Osobennosti gumusa chernozemov obyknovennykh Kamennoi Stepi (Features of humus of ordinary chernozems of the Kamennaya Steppe), Vestnik Moskovskogo universiteta. Seriya 17: Pochvovedenie, 2007, No. 2, pp. 3–9.

19. Mezger T., The Rheology Handbook for users of rotational and oscillatory rheometers, Hanover: Vincentz, 2011, 436 p.

20. Kiselev M.G., Savich V.V., Pavich T.P., Opredelenie kraevogo ugla smachivaniya na ploskikh poverkhnostyakh (Determination of the wetting angle on flat surfaces), Nauka i tekhnika, 2006, No. 1, pp. 38–41.

21. Moradi A.B., Carminati A., Lamparter A., Woche S.K., Bachmann J., Vetterlein D., Vogel H.J., Oswald S.E., Is the Rhizosphere Temporarily Water Repellent? Vadose Zone Journal, 2012, Vol. 11, Iss. 3, p. 8.

22. Kogut B.M., Titova N.A., Buleeva V.S., Antropogennaya transformatsiya kachestvennogo sostava gumusa chernozemov Kamennoi Stepi (Anthropogenic transformation of the qualitative composition of humus of chernozems of the Kamennaya Steppe), Dokuchaev Soil Bulletin, 2009, Vol. 64, pp. 41–49, DOI: 10.19047/0136-1694-2009--41-49.

23. Papierowska E., Matysiak W., Szatyłowicz J., Debaene G., Urbanek E., Kalisz B., Łachacz A. Compatibility of methods used for soil water repellency determination for organic and organo-mineral soils, Geoderma, 2018, Vol. 314, pp. 221–231, DOI: 10.1016/j.geoderma.2017.11.012.

24. Kononova M.M., Bel'chikova N.P., Protsessy prevrashcheniya organicheskikh veshchestv v obyknovennom chernozeme pri primenenii kompleksa Dokuchaeva-Kostycheva-Vil'yamsa (The processes of conversion of organic substances in ordinary chernozem when using the Dokuchaev-Kostychev-Williams complex), In: Voprosy travopol'noi sistemy zemledeliya (Issues of grass field farming system), Moscow: Izd-vo AN SSSR, 1953, Vol. II, pp. 303–360.

25. Ryley D.J., Khoshaim B.H., New method of determining contact-angle made by a sessile drop upon a horizontal surface (sessile drop contact-angle), Journal of Colloid and Interface Science, 1977, Vol. 59, Iss. 2., pp. 243–251.

26. Korolev V.A., Izmenenie osnovnykh fizicheskikh svoistv chernozemov obyknovennykh pod vliyaniem orosheniya (Changes in the basic physical properties of ordinary chernozems under the influence of irrigation), Pochvovedenie, 2008, No. 10, pp. 1234–1240.

27. Shang J., Flury M., Harsh J.B., Zollars R.L., Comparison of different methods to measure contact angles of soil colloids, Journal of Colloid and Interface Science, 2008, Vol. 328, Iss. 2, pp. 299–307.

28. Kuzelev M.M., Mamontov V.G., Syunyaev N.K., Sviridov A.K., Cherenkov V.V., Gumusovoe sostoyanie obyknovennykh chernozemov estestvenno-antropogennogo landshafta Kamennoi Stepi (The humus state of ordinary chernozems of the natural anthropogenic landscape of the Stone Steppe), Izvestiya TSKhA, 2007, No. 3, pp. 38–46.

29. Vogelmann E.S., Reichert J.M., Prevedello J., Awe G.O., Mataix-Solera J., Can occurrence of soil hydrophobicity promote the increase of aggregates stability? Catena, 2013, Vol. 110, pp. 24–31, DOI: 10.1016/j.catena.2013.06.009.

30. Lebedeva I.I., Bazykina G.S., Grebennikov A.M., Cheverdin Y.I., Bespalov V.A., The experience of the complex assessment of the impact of the length of agricultural use on properties and regimes of agrochernozems of Stony Steppe, Dokuchaev Soil Bulletin, 2016, Vol. 83, pp. 77–102, DOI: 10.19047/0136-1694-2016-83-77-102.

31. Wallis M., Horne D., Soil water repellency, Advances in soil science, Springer, 1992, pp. 91–146.

32. Mamontov V.G., Sokolovskaya E.L., Elementnyi i molekulyarno-massovyi sostav labil'nykh gumusovykh veshchestv chernozema obyknovennogo kamennoi stepi (The elemental and molecular mass composition of labile humic substances of chernozem of ordinary stone steppe), Izvestiya TSKhA, 2018, No. 1, pp. 130–138.

33. Woche S.K., Goebel M.O., Kirkham M.B., Horton R., Van der Ploeg R.R., Bachmann J., Contact angle of soils as affected by depth, texture, and land management, European Journal of Soil Science, 2005, Vol. 56, Iss. 2, pp. 239–251.

34. Matveeva N.V., Milanovskii E.Yu., Rogova O.B., The method of preparing soil samples for soil – water contact angle measurement using sessile-drop technique, Dokuchaev Soil Bulletin, 2019, No. 97, pp. 91–112, DOI: 10.19047/0136-1694-2019-97-91-112.

35. World Reference Base for soil resources 2014: international soil classification system for naming soils and creating legends for soil maps, World Soil Resources Report (106).

36. Milanovskii E.Yu., Gumusovye veshchestva pochv kak prirodnye gidrofobno-gidrofil'nye soedineniya (Humic substances of soils as natural hydrophobic-hydrophilic compounds), Moscow: GEOS, 2009, 188 p.

37. Wu W.J., Baseline studies of The Clay Minerals Society Source Clays: Colloid and surface phenomena, Clays and Clay Minerals, 2001, Vol. 49, Iss. 5, pp. 446–452.

38. Milanovskii E.Yu., Shein E.V., Funktsional'naya rol' amfifil'nykh komponentov gumusovykh veshchestv v protsessakh gumuso-strukturoobrazovaniya i v genezise pochv (The functional role of amphiphilic components of humic substances in the processes of humus structure formation and in the soil genesis), Pochvovedenie, 2002, No. 10, pp. 1201–1213.

39. Yang S., Gong A.M., Wu J.H., Lu T.H., Effect of contact angle on matric suction of unsaturated soil, Rock and Soil Mechanics, 2015, Vol. 36, Iss. 3, pp. 674–678.

40. Shein E.V., Rusanov A.M., Zasypkina D.I., Nikolaeva E.I., Anilova L.V., Pochvennaya struktura i organicheskoe veshchestvo tipichnykh chernozemo Predural'ya pod lesom i mnogoletnei pashnei (The soil structure and organic matter of typical chernozems of the Urals under a forest and perennial arable land), Vestnik Orenburgskogo gosudarstvennogo universiteta, 2005, No. 2, pp. 113–117.

41. Yudina A.V., Fomin D.S., Kotelnikova A.D., Milanovskii E.Yu., From the notion of elementary soil particle to the particle-size and microaggregate-size distribution analyses: A review, Eurasian soil science, 2018, Vol. 51, Iss. 11, pp. 1326–1347.

42. Skryl'nik E.V., Shevchenko N.V., Popirnyi M.A., Nikolov O.T., Konformatsionnye perestroiki suprastruktury guminovykh kislot chernozema tipichnogo v zavisimosti ot sposobov obrabotki pochvy (Conformational rearrangements of the suprastructure of humic acids of chernozem typical depending on soil cultivation methods), Izvestiya Natsional'noi akademii nauk Belarusi. Seriya biologicheskikh nauk, 2018, Vol. 63, Iss. 2, pp. 209–221.

43. Zickenrott I.M., Woche S.K., Bachmann J., Ahmed M.A., Vetterlein D., An efficient method for the collection of root mucilage from different plant species: A case study on the effect of mucilage on soil water repellency, J. Plant Nutr. Soil Sci., 2016, Vol. 179, pp. 294–302.

44. Stakhurlova L.D., Svistova I.D., Shcheglov D.I., Biologicheskaya aktivnost' kak indikator plodorodiya chernozemov v razlichnykh biotsenozakh (Biological activity as an indicator of the fertility of chernozems in various biocenoses), Pochvovedenie, 2007, No. 6, pp. 769–774.

45.

46. Khaidapova D.D., Milanovskii E.Yu., Chestnova V.V., Otsenka reologicheskimi metodami vosstanovleniya struktury pochv pod vliyaniem vyrashchivaniya lesopolos na antropogenno narushennykh pochvakh (Evaluation by rheological methods of restoration of soil structure under the influence of growing forest belts on anthropogenically disturbed soils), Vestnik Altaiskogo gosudarstvennogo agrarnogo universiteta, 2014, No. 6, pp. 53–58.

47. Khaidapova D.D., Chestnova V.V., Shein E.V., Milanovskii E.Yu., Reologicheskie svoistva chernozemov tipichnykh (Kurskaya oblast') pri razlichnom zemlepol'zovanii (Rheological properties of typical chernozems (Kursk region) with different land use), Pochvovedenie, 2016, No. 8, pp. 955–963.

48. Cheverdin Yu.I., Bespalov V.A., Prostranstvennoe var'irovanie soderzhaniya gumusa v chernozemakh Kamennoi Stepi (Spatial variation of the humus content in chernozems of the Kamennaya Steppe), Plodorodie, 2011, No. 4, pp. 28–29.

49. Shein E.V., Kurs fiziki pochv (Soil physics course), Moscow: MGU, 2005, 432 p.

50. Shein E.V., Milanovskii E.Yu., Khaidapova D.D., Ustoichivost' pochvennoi struktury i organicheskoe veshchestvo pochv (Stability of the soil structure and organic matter of soils), In: Rol' pochv v biosfere. Trudy in-ta pochvovedeniya MGU im. MV Lomonosova i RAN, 2002, No. 1, pp. 129–151.

51. Shishov L.L., Tonkonogov V.D., Lebedeva I.I., Gerasimova M.I., Klassifikatsiya i diagnostika pochv Rossii (Classification and diagnostics of Russian soils), Smolensk: Oikumena, 2004. 341 p.

52. Shcheglov D.I., Chernozemy tsentra Russkoi ravniny i ikh evolyutsiya pod vliyaniem estestvennykh i antropogennykh faktorov: Avtoref. dis. ... doct. biol. nauk (Chernozems of the Center of the Russian Plain and their Evolution under the Influence of Natural and Anthropogenic Factors, Extended abstract of cand. biol. sci. thesis), Voronezh, 1995, 46 p.

53. Shcheglov D.I., Gorbunova N.S., Semenova L.A., Khatuntseva O.A., Mikroelementy v pochvakh sopryazhennykh landshaftov Kamennoi stepi razlichnoi stepeni gidromorfizma (Microelements in the soils of the associated landscapes of the Kamennaya Steppe of varying degrees of hydromorphism), Pochvovedenie, 2013, No. 3, pp. 282–290.

54. Adamson A., Physical chemistry of surfaces 5th edn, New York, NY John Wiley & Sons Inc, 1990, pp. 379–420.

55. Ahmed M.A., Kroener E., Benard P., Zarebanadkouki M., Kaestner A., Carminati A., Drying of mucilage causes water repellency in the rhizosphere of maize: Measurements and modelling, Plant Soil, 2016, Vol. 407, Iss. 1–2, pp. 161–171.

56. Aquino A.J., Tunega D., Pašalić H., Schaumann G.E., Haberhauer G., Gerzabek M.H., Lischka H., Molecular dynamics simulations of water molecule-bridges in polar domains of humic acids, Environmental science & technology, 2011, Vol. 45, No. 19, pp. 8411–8419.

57. Bachmann J., Contact angle and surface charge of wettable and hydrophobic silt particles, J. Soil Sci. Plant Nutr., 2001, Vol. 1, pp. 26–33.

58. Bachmann J., Ellies A., Hartge K.H., Development and application of a new sessile drop contact angle method to assess soil water repellency, Journal of Hydrology, 2000, Vol. 231, pp. 66–75, DOI: 10.1016/S0022-1694(00)00184-0.

59. Bachmann J., Guggenberger G., Baumgartl T., Ellerbrock R.H., Urbanek E., Goebel M.O., Kaiser K., Horn R., Fischer W.R., Physical carbon‐sequestration mechanisms under special consideration of soil wettability, Journal of Plant Nutrition and Soil Science, 2008, Vol. 171, Iss. 1, pp. 14–26.

60. Bachmann J., Woche S.K., Goebel M.O., Kirkham M.B., Horton R., Extended methodology for determining wetting properties of porous media, Water Resources Research, 2003, Vol. 39, No. 12, p. 14.

61. Bahrani B., Mansell R.S., Hammond L.C., Using infiltrations of heptane and water into soil columns to determine soil-water contact angles, Soil Science Society of America Journal, 1973, Vol. 37, Iss. 4, pp. 532–534.

62. Benard P., Zarebanadkouki M., Hedwig C., Holz M., Ahmed M., Carminati A., Pore-scale distribution of mucilage affecting water repellency in the rhizosphere, Vadose Zone Journal, 2018, Vol. 17, Iss. 1, pp. 1–9.

63. Burghardt W., Determination of the wetting characteristics of peat soil extracts by contact-angle measurements, Zeitschrift Fur Pflanzenernahrung Und Bodenkunde, 1985, Vol. 148, No. 1, pp. 66–72.

64. Carrillo M.L.K., Letey J., Yates S.R., Measurement of initial soil-water contact angle of water repellent soils, Soil Science Society of America Journal, 1999, Vol. 63, Iss. 3, pp. 433–436.

65. Cihlář Z., Vojtová L., Conte P., Nasir S., Kučerík J., Hydration and water holding properties of cross-linked lignite humic acids, Geoderma, 2014, Vol. 230, pp. 151–160.

66. De Gryze S., Jassogne L., Bossuyt H., Six J., Merckx R., Water repellence and soil aggregate dynamics in a loamy grassland soil as affected by texture, European Journal of Soil Science, 2006, Vol. 57, Iss. 2, pp. 235–246.

67. Dlapa P., Doerr S., Lichner L., Sir M., Tesar M., Effect of kaolinite and Ca-montmorillonite on the alleviation of soil water repellency, Plant Soil and Environment, 2004, Vol. 50, Iss. 8, pp. 358–363.

68. Doerr S.H., On standardizing the ‘Water Drop Penetration Time’ and the ‘Molarity of an Ethanol Droplet’ techniques to classify soil hydrophobicity: A case study using medium textured soils, Earth Surface Processes and Landforms, 1998, Vol. 23, No. 7, pp. 663–668, DOI: 10.1002/(SICI)1096-9837(199807)23:7<663::AID-ESP909>3.0.CO;2-6.

69. Doerr S.H., Shakesby R.A., Walsh R.P.D., Soil water repellency: its causes, characteristics and hydro-geomorphological significance, Earth-Science Reviews, 2000, Vol. 51, No. 1–4, pp. 33–65, DOI: 10.1016/S0012-8252(00)00011-8.

70. Ellerbrock R.H., Gerke H.H., Bachmann J., Goebel M.O., Composition of organic matter fractions for explaining wettability of three forest soils, Soil Science Society of America Journal, 2005, Vol. 69, Iss. 1, pp. 57–66.

71. Goebel M.O., Bachmann J., Woche S.K., Fischer W.R., Horton R., Water potential and aggregate size effects on contact angle and surface energy, Soil Science Society of America Journal, 2004, Vol. 68, Iss. 2, pp. 383–393.

72. Haas C., Gerke H.H., Ellerbrock R.H., Hallett P.D., Horn R., Relating soil organic matter composition to soil water repellency for soil biopore surfaces different in history from two Bt horizons of a Haplic Luvisol, Ecohydrology, 2018, Vol. 11, Iss. 6, p. 11.

73. Hajnos M., Calka A., Jozefaciuk G., Wettability of mineral soils, Geoderma, 2013, No. 206, pp. 63–69.

74. Jaramillo D.F., Effect of soil drying temperature on water repellence in Andisols under Pinus patula cover, Research report, National University of Colombia, Medellin, 2003, 36 p.

75. Jiménez J.J., Lorenz K., Lal R., Organic carbon and nitrogen in soil particle-size aggregates under dry tropical forests from Guanacaste, Costa Rica – implications for within-site soil organic carbon stabilization, Catena, 2011, Vol. 86, Iss. 3, pp. 178–191.

76. Kholodov V.A., Yaroslavtseva N.V., Yashin M.A., Frid A.S., Lazarev V.I., Tyugai Z.N., Milanovskiy E.Y., Contact angles of wetting and water stability of soil structure, Eurasian Soil Science, 2015, Vol. 48, No. 6, pp. 600–607.

77. Kleber M., Sollins P.,·Sutton R., A conceptual model of organo-mineral interactions in soils: self-assembly of organic molecular fragments into zonal structures on mineral surfaces, Biogeochemistry, 2007, Vol. 85, No. 1, pp. 9–24.

78. Kraemer F.B., Hallett P.D., Morras H., Garibaldi L., Cosentino D., Duval M., Galantini J., Soil stabilisation by water repellency under no-till management for soils with contrasting mineralogy and carbon quality, Geoderma, 2019, No. 355, p. 113902.

79. Lamparter A., Bachmann J., Woche S.K., Determination of Small-Scale Spatial Heterogeneity of Water Repellency in Sandy Soils, Soil Science Society of America Journal, 2010, Vol. 74, Iss. 6, pp. 2010–2012.

80. Lilliefors H.W., On the Kolmogorov-Smirnov test for normality with mean and variance unknown, Journal of the American statistical Association, 1967, Vol. 62, Iss. 318, pp. 399–402.

81. Liu Z., Yu X., Wan L., Capillary rise method for the measurement of the contact angle of soils, Acta Geotechnica, 2016, Vol. 11, Iss. 1, pp. 21–35.

82. Markgraf W., Horn R., Peth S., An approach to rheometry in soil mechanics–Structural changes in bentonite, clayey and silty soils, Soil Tillage Res., 2006, Vol. 91, pp. 1–14.

83. Markgraf W., Watts C.W., Whalley W.R., Hrkac T., Horn R., Influence of organic matter on rheological properties of soil, Applied Clay Science, 2012, Vol. 64, pp. 25–33.

84. Mezger T., The Rheology Handbook for users of rotational and oscillatory rheometers, Hanover: Vincentz, 2011, 436 p.

85. Moradi A.B., Carminati A., Lamparter A., Woche S.K., Bachmann J., Vetterlein D., Vogel H.J., Oswald S.E., Is the Rhizosphere Temporarily Water Repellent? Vadose Zone Journal, 2012, Vol. 11, Iss. 3, p. 8.

86. Papierowska E., Matysiak W., Szatyłowicz J., Debaene G., Urbanek E., Kalisz B., Łachacz A. Compatibility of methods used for soil water repellency determination for organic and organo-mineral soils, Geoderma, 2018, Vol. 314, pp. 221–231, DOI: 10.1016/j.geoderma.2017.11.012.

87. Ryley D.J., Khoshaim B.H., New method of determining contact-angle made by a sessile drop upon a horizontal surface (sessile drop contact-angle), Journal of Colloid and Interface Science, 1977, Vol. 59, Iss. 2., pp. 243–251.

88. Shang J., Flury M., Harsh J.B., Zollars R.L., Comparison of different methods to measure contact angles of soil colloids, Journal of Colloid and Interface Science, 2008, Vol. 328, Iss. 2, pp. 299–307.

89. Vogelmann E.S., Reichert J.M., Prevedello J., Awe G.O., Mataix-Solera J., Can occurrence of soil hydrophobicity promote the increase of aggregates stability? Catena, 2013, Vol. 110, pp. 24–31, DOI: 10.1016/j.catena.2013.06.009.

90. Wallis M., Horne D., Soil water repellency, Advances in soil science, Springer, 1992, pp. 91–146.

91. Woche S.K., Goebel M.O., Kirkham M.B., Horton R., Van der Ploeg R.R., Bachmann J., Contact angle of soils as affected by depth, texture, and land management, European Journal of Soil Science, 2005, Vol. 56, Iss. 2, pp. 239–251.

92. World Reference Base for soil resources 2014: international soil classification system for naming soils and creating legends for soil maps, World Soil Resources Report (106).

93. Wu W.J., Baseline studies of The Clay Minerals Society Source Clays: Colloid and surface phenomena, Clays and Clay Minerals, 2001, Vol. 49, Iss. 5, pp. 446–452.

94. Yang S., Gong A.M., Wu J.H., Lu T.H., Effect of contact angle on matric suction of unsaturated soil, Rock and Soil Mechanics, 2015, Vol. 36, Iss. 3, pp. 674–678.

95. Yudina A.V., Fomin D.S., Kotelnikova A.D., Milanovskii E.Yu., From the notion of elementary soil particle to the particle-size and microaggregate-size distribution analyses: A review, Eurasian soil science, 2018, Vol. 51, Iss. 11, pp. 1326–1347.

96. Zickenrott I.M., Woche S.K., Bachmann J., Ahmed M.A., Vetterlein D., An efficient method for the collection of root mucilage from different plant species: A case study on the effect of mucilage on soil water repellency, J. Plant Nutr. Soil Sci., 2016, Vol. 179, pp. 294–302.

97.