Effect of top soil wettability on water evaporation and plant growth

• Published in: Journal of colloid and interface science 2015-07, Vol.449, p.506-513
• Main Authors: Gupta, Bharat, Shah, D.O., Mishra, Brijesh, Joshi, P.A., Gandhi, Vimal G., Fougat, R.S.
• Format: Article
• Language: English
• Subjects: Biomass; Chick pea; Cicer - growth & development; Diffusion controlled transport of water vapour; Growth parameters; Hydrophilic soil; Hydrophobic and Hydrophilic Interactions; Hydrophobic soil; Soil - chemistry; Steam - analysis; Water - chemistry; Water retention by soil; Wettability
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2015.02.018

[Display omitted] In general, agricultural soil surfaces being hydrophilic in nature get easily wetted by water. The water beneath the soil moves through capillary effect and comes to the surface of the soil and thereafter evaporates into the surrounding air due to atmospheric conditions such as sunlight, wind current, temperature and relative humidity. To lower the water loss from soil, an experiment was designed in which a layer of hydrophobic soil was laid on the surface of ordinary hydrophilic soil. This technique strikingly decreased loss of water from the soil. The results indicated that the evaporation rate significantly decreased and 90% of water was retained in the soil in 83h by the hydrophobic layer of 2cm thickness. A theoretical calculation based on diffusion of water vapour (gas phase) through hydrophobic capillaries provide a meaningful explanation of experimental results. A greater retention of water in the soil by this approach can promote the growth of plants, which was confirmed by growing chick pea (Cicer arietinum) plants and it was found that the length of roots, height of shoot, number of branches, number of leaves, number of secondary roots, biomass etc. were significantly increased upon covering the surface with hydrophobic soil in comparison to uncovered ordinary hydrophilic soil of identical depth. Such approach can also decrease the water consumption by the plants particularly grown indoors in residential premises, green houses and poly-houses etc. and also can be very useful to prevent water loss and enhance growth of vegetation in semi-arid regions.