Quantifying soil pores geometric properties using fluorescent dye method

Document Type : Research Paper


University of Tehran


Soil porosity plays the major role in relation with soil genesis, soil processes control and its interactions with the environmental factors and translocation of water and solutes. The heterogeneity of soil porosity components is simplified by considering some assumptions such as taking into accounr all of the pores do actively and are spherical. Micromorphological approaches by direct observation and determination of soil pores geometry prepares detailed characterization of soil pores. The aim of this study was quantifying soil pores geometric properties using flouerecent dye method. 39 undisturbed soil samples impregnated with a mixture of resin-acetone containing flouerecent dye, dryed out and cut. Then 40 digital images were taken from each sample under ultraviolet light. The images were thresholded until the soil pores distinguished as white from the matrix. The results of pores based on area, perimeter, elongation, compaction, roundness, ferret diameter, long and short axis diameters were classified visually. The quantitative results of pores area showed that the pores smaller than 100 μm2 in the plough layer (depth < 35 cm) were less than 16% while it increases to > 29% in the plough pan due to compaction. Pores with > 100 μm2 area in plough layer increases > 80% of total porosity. The dominant compaction class was the (0.3-0.5 unit less) that its maximum percent was (56.94%) in the depth of 35-30 cm. According to the elongation index the most elongated pores (the class <0.1) was observed in the surface layers (0-10 cm) while it decreased to 33.8% in 30-35 cm. From the roundness point of view more than 55% of pores in all studied depths showed the roundness index of 0.05-0.1.


Main Subjects

Alaoui, A., Lipiec, J., & Gerke, H. H. (2011). A review of the changes in the soil pore system due to soil deformation: A hydrodynamic perspective. Soil and Tillage Research115, 1-15.
Arah, J.R.M. and Ball, B.C., 1994. A functional model of soil porosity used to interpret measurements of gas diffusion. European Journal of Soil Science, 45(2), pp.135-144.
Cabidoche, Y.M. and Guillaume, P., 1998. A casting method for the three-dimensional analysis of the intraprism structural pores in vertisols. European Journal of Soil Science, 49(2), pp.187-196.
Cooper, M., Vidal-Torrado, P., & Chaplot, V. (2005). Origin of microaggregates in soils with ferralic horizons. Scientia Agricola62(3), 256-263.
Cooper, M., Boschi, R. S., Silva, V. B. D., & Silva, L. F. S. D. (2016). Software for micromorphometric characterization of soil pores obtained from 2-D image analysis. Scientia Agricola73(4), 388-393.
Dec, D., Dörner, J., Becker-Fazekas, O., & Horn, R. (2008). Effect of bulk density on hydraulic properties of homogenized and structured soils. RC Suelo Nutr. Veg8(1), 1-13.
FitzPatrick, E. A., & Fitzpatrick, E. A. (1993). Soil microscopy and micromorphology (p. 304). Chichester: John Wiley & Sons.
Beckmann, W., & Geyger, E. V. (1967). Entwurf einer Ordnung der natürlichen Hohlraum-, aggregat-und Strukturformen im Boden. Die Mikromorphometrische Bodenanalyse, 165-188.
Hirmas, D. R., Giménez, D., Mome Filho, E. A., Patterson, M., Drager, K., Platt, B. F., & Eck, D. V. (2016). Quantifying Soil Structure and Porosity Using Three-Dimensional Laser Scanning. In Digital Soil Morphometrics (pp. 19-35). Springer International Publishing.
Manual of Image Tool. (2001). UTHSCSA.
Martys, N.S., Torquato, S. and Bentz, D.P., 1994. Universal scaling of fluid permeability for sphere packings. Physical Review E, 50(1), p.403.
Nimmo, J. R. (2004). Porosity and pore size distribution. Encyclopedia of Soils in the Environment3, 295-303.
Oh, S., Kim, Y. K., & Kim, J. W. (2015). A modified van Genuchten-Mualem Model of hydraulic conductivity in Korean Residual Soils. Water7(10), 5487-5502.
Pachepsky, Y.A., Shcherbakov, R.A. and Korsunskaya, L.P., 1995. Scaling of soil water retention using a fractal model. Soil science, 159(2), pp.99-104.
Pagliai, M. and Vignozzi, N., 2003. Image analysis and microscopic techniques to characterize soil pore system. Physical methods in agriculture: Approach to precision and quality. Kluwer Acad. Publ., New York, pp.13-38.
Passoni, S., Borges, F. D. S., Pires, L. F., Saab, S. D. C., & Cooper, M. (2014). Software Image J to study soil pore distribution. Ciência e Agrotecnologia38(2), 122-128.
Perfect, E., McLaughlin, N.B., Kay, B.D. and Topp, G.C., 1996. An improved fractal equation for the soil water retention curve. Water Resources Research, 32(2), pp.281-287.
Perret, J., Prasher, S. O., Kantzas, A., & Langford, C. (1999). Three-dimensional quantification of macropore networks in undisturbed soil cores. Soil Science Society of America Journal63(6), 1530-1543.
Previatello da Silva, L., & de Jong Van Lier, Q. (2015). Pore space connectivity and porosity using CT scans of tropical soils. In EGU General Assembly Conference Abstracts (Vol. 17, p. 1528).
Russ, J. C. (2011). Processing binary images. The Image Processing Handbook4, 410-412.
Schoonover, J. E., & Crim, J. F. (2015). An introduction to soil concepts and the role of soils in watershed management. Journal of Contemporary Water Research & Education154(1), 21-47.
Schoeneberger, P. J., Wysocki, D. A., & Benham, E. C. (2012). Field book for describing and sampling soils, Version 3.0. Natural Resources Conservation Service, National Soil Survey Center, Lincoln, NE, 36.
Tuller, M., & Or, D. (2004). Retention of water in soil and the soil water characteristic curve. Encyclopedia of Soils in the Environment4, 278-289.
Vergani, C., & Graf, F. (2015). Soil permeability, aggregate stability and root growth: a pot experiment from a soil bioengineering perspective. Ecohydrology.
Verruijt, A. (2001). Soil Mechanics. Delft University of Technology, Netherlands.
Zdravkov, B., Čermák, J., Šefara, M., & Janků, J. (2007). Pore classification in the characterization of porous materials: A perspective. Open Chemistry5(2), 385-395.