RESEARCH PAPER
Moisture dynamics as related to capillary and drainable pores in the Nile Delta soils
 
More details
Hide details
1
Department of Soil Science, Faculty of Agriculture, Menoufia University, Egypt
CORRESPONDING AUTHOR
Abdelmonem Mohamed Amer   

Department of Soil Science, Faculty of Agriculture, Menoufia University, Mustafa Kamel, 32511, Shebin El-Kom, Egypt
Publish date: 2019-09-10
Final revision date: 2019-08-10
Acceptance date: 2019-08-27
 
Acta Agroph. 2019, 26(2), 29–43
KEYWORDS
TOPICS
ABSTRACT
The dynamic of soil moisture may be studied through water flux, storage, moisture conductivity and movement into the soil pore spaces. The volume of pore space in the soil and also the size, shape, type, continuity and distribution of the pores are important characteristics related to the storage, conductivity and movement of water and gases. The movement of water by gravitational forces in the natural soils occurs principally through the non-capillary pores (i.e. rapidly drained pores), while other movements occur in capillaries which may be classified as coarse and fine capillary pores. The unsaturated condition of soil water is a common state in nature after rainfall or as a result of irrigation, therefore, the purpose of this study was to develop equations to describe and estimate the unsaturated hydraulic conductivity K(θ) in relation to soil pore-size classes that contained the available water in the soil root zone. The equations were based on a water-retention curve, saturated hydraulic conductivity and pore-size function measured from undisturbed cores. The equations were applied to three soil profiles from the Nile Delta and compared with measured K(θ) data from two field experiments, which were conducted in clay in an unsaturated condition and in sandy soil areas using the internal drainage in situ method. The pore size function f(r) represents the fraction of the total pore whichvolume, which was contributed by pores with radii from 0 to ∞ at the prevailing degree of saturation. Data showed the applicability of the suggested equations for calculating unsaturated hydraulic conductivity in the soil pores even for soils with a high proportion of clay.
CONFLICT OF INTEREST
The Author does not declare conflict of interest.
 
REFERENCES (22)
1.
Amer A.M, Logsdon S.D., Davis D., 2009. Prediction of hydraulic conductivity in unsaturated soils. Soil Sci., 174(9), 508-515, https://doi.org/10.1097/SS.0b0....
 
2.
Amer A.M., 1993. Surface area measurements as related to water vapor adsorption in arid soils of Egypt. Proc. Int. Conf. Desert Develop. 25-30 July, Mexico City, Mexico, 619-627.
 
3.
Amer A.M., 1982. Effect of the overburden pressure on the capillary sorption potential of water in swelling soils. Ph.D. Thesis, Faculty of Soil Sci., Moscow State Univ., Moscow.
 
4.
Amer A.M., 2001. Soil water movement and irrigation requirements (in Arabic). 1st Ed. El-Dar Al-Arabia for Publish., Cairo, Egypt, 438.
 
5.
Amer A.M., 2002. Drainable and water-filled pores as related to water storage and conductivity in agricultural soils of the Nile Delta, SIL Proceedings, 1922-2010, 28, 4, 1912-1919, https://doi.org/10.1080/036807....
 
6.
Amer A.M., 2009. Moisture adsorption capacity and surface area as deduced from vapour pressure isotherms in relation to hygroscopic water of soils. Biologia, 64, 3, 516-521, https://doi.org/10.2478/s11756....
 
7.
Baver L.D., Gardner W.R., 1972. Soil physics. 4th ed. John Wiley & Sons, New York, 498.
 
8.
Dane J.H., Topp G.C. (Eds), 2002. Methods of soil analysis, Part 4, Physical methods. SSSA, Madison, 1692.
 
9.
El-Sharkawy A.F., 1994. Study of water imbibition in soil agricultural soils. M.Sc. Thesis, Faculty of Agriculture, Menoufia University, Shebin El-Kom, Egypt.
 
10.
Hillel D., 1980. Fundamentals of soil physics. Academic Press, New York. 413, https://doi.org/10.1016/B978-0....
 
11.
Khan G.S., Afzal T., 1989. Hydraulic characteristics of some important soil series of Pakistan. In: Soil physics in stress environments (Ed. M. Ahmed). Proceed. Inter. Sym. Soil physics in stress environments. 22-26 January. Islamabad, Pakistan, 222-237.
 
12.
Khater E.A., 1978. Physical and micro-morphological studies in relation to soil moisture in alluvial soils of Egypt. Ph.D. Thesis, Fac. of Agric., Cairo Univ.
 
13.
Klute A., 1972. The determination of hydraulic conductivity and diffusivity of unsaturated soil. Soil Sci., 113(4), 264-276, https://doi.org/10.1097/000106....
 
14.
Kosugi K., 1999. General model for unsaturated hydraulic conductivity for soils with lognormal pore-size distribution. Soil Sci. Soc. Am. J., 63, 270-277, https://doi.org/10.2136/sssaj1.... 03615995006300020003x.
 
15.
Marshall T.J., 1956. Relation between water and soil. Technical Communication No. 50, Commonwealth Bureau of Soils, Farenham Royal, Bucks, England.
 
16.
Mualem Y., 1976. A new model predicting the hydraulic conductivity of unsaturated porous media. Water Res. Res., 12, 513-522, https://doi.org/10.1029/WR012i....
 
17.
Poulsen T.G., Moldrup P., Iversen B.V., Jacobsen O.H., 2002. Three-region Campbell model for unsaturated hydraulic conductivity in undisturbed soils. Soil Sci. Soc. Am. J., 66, 744-752, https://doi.org/10.2136/sssaj2....
 
18.
Schaap M.G., van Genuchten M.Th., 2006. A modified Mualen-van Genuchten formulation for improved description of the hydraulic conductivity near saturation. Vadose Zone J., 5, 27-34, https://doi.org/10.2136/vzj200....
 
19.
Sparks D.L. (Ed.), 1996. Methods of soil analysis, Part 3, Chemical methods. ASA, SSSA, Madison.
 
20.
Stakman W.P., 1966. Determination of pore size by the air bubbly pressure method. Proceedings of UNESCO Symposium on Water in the Unsaturated Zone, 366-372.
 
21.
Sudnitcyn E.E., 1979. Soil water movement and water requirements of crops. Moscow Univ. Ezdat, Moscow.
 
22.
Vomocil J.A., 1965. “Porosity” in methods of soil analysis., Black. Agronomy Monograph, 9(I), 299-314, Academic Press, New York.
 
eISSN:2300-6730
ISSN:1234-4125