The Effect of Different Na/K Ratios in Soil Solution on Aggregate Tensile Strength and Friability

Document Type : Research Paper

Authors

Abstract

This research was carried out to study the effect of different ratio of Na/K in soil solution on dispersible clay, aggregate tensile strength and soil friability using the cation ratio of soil structural stability (CROSS) index. In order to apply different potassium concentrations, 6 treatments with the same EC (3 dS m-1) including 0 to 27.2 meqL-1 K+ and another six treatments with EC=6 dS m-1 including 0 to 54.4 meqL-1 K+ were prepared and added to soil. Soil friability was calculated and compared through two methods i.e. the coefficient of variation (F1) and ranking order (F2). The results showed that increasing the K+ concentration in treatments relative to Na+ could increase the water dispersible clay. Also, the results of aggregates tensile strength test showed that in treatments with EC=3 dS m-1 by increasing the K+ value, the soil strength decreased but with increasing the SAR value, soil strength increased. Maximum amount of tensile strength (142 kPa) was observed in treatment 1 with CROSS = 25.7 and SAR=22.9 and the minimum amount (87 kPa) was in treatment 5 with CROSS=14.8 and SAR=0.99. This trend was not observed in treatments with EC=6 dS m-1 and the aggregate tensile strengths were almost similar in all treatments. The results demonstrated that soil friability (F1 & F2) increased with increasing the dispersible clay at EC=3. Comparison of the results of tensile strength and friability revealed that F1 was inappropriate parameter for expression of soil friability while F2 showed the good agreement with the strength and friability amounts (in treatments with EC=3). In treatments with EC=6, the effect of dispersible clay on tensile strength and friability was not observed, probably due to the higher concentration of the soil solution. 

Keywords

References

بهمن زاده ه، 1387.  ارزیابی تردی خاک در برخی از خاک­های همدان. پایان­نامه کارشناسی ارشد خاک­شناسی، دانشکده کشاورزی، دانشگاه بوعلی سینا.
تاجیک ف،  رحیمی ح  و  پذیرا  الف، 1381. اثر مواد آلی خاک، هدایت الکتریکی و نسبت جذب سدیم بر مقاومت کششی خاکدانه­ها. مجله علوم و فنون کشاورزی و منابع طبیعی. جلد 6، شماره 3،  صفحه­های 151تا160.
Barzegar AR, Oades JM, Rengasamy P and Giles L, 1994. Effect of sodicity and salinity on disaggregation and tensile strength of an Alfisol under different cropping systems. Soil and Tillage Research 32: 329-345.
Barzegar AR, Oades JM, Rengasamy P and Murray RS, 1995. Tensile strength of dry, remoulded soils as affected by properties of the clay function. Geoderma 65: 93-108.
Dexter AR and Chan KY, 1991. Soil mechanical properties as influenced by exchangeable cations. Journal of Soil Science 42: 219-226.
Dexter AR and Kroesbergen B, 1985. Methodology for determination of tensile strength of soil aggregates. Journal of Agriculture Engineering Research 31: 139-147.
Dexter AR and Watts CW, 2000. Tensile strength and friability. Pp. 405-433. In: Smith, KA and Mullins, CE (Eds.) "Soil and Environmental Analysis: Physical Methods". 2nd Edition. Marcel Dekker, Inc.
Gee, G.W., and Bauder, J.W. 1986. Particle–size analysis. Pp. 383-411. In: Klute, A (Ed.) "Methods of Soil Analysis. Part 1- Physical and mineralogical methods" 2nd edition. Agronomy No.9. America Society of Agronomy, Inc. Soil Science Society of America, Madison, Wisconsin. USA.
Hallett PD, Dexter AR and Seville JPK, 1995a. Identification of pre-existing cracks on soil fracture surfaces using dye. Soil and Tillage Research 33: 163-184.
Hallett PD, Bird NRA, Dexter AR and Seville JPK, 1995. The application of fracture mechanics to crack propagation in dry soil. European Journal of Soil Science 49: 591- 599.
Hillel D, 1980. Application of Soil Physics. London, Academic Press Inc. 771 p.
Kay BD and Dexter AR, 1992. The influence of dispersible clay and wetting/drying cycles on the tensile strength of a red-brown earth. Australian Journal of Soil Research 30: 297-310.
Marchuk A and Rengasamy P, 2012.  Threshold electrolyte concentration and dispersive potential in relation to CROSS in dispersive soils. Soil Research 50: 473–481.
Marchuk A, Rengasamy P and McNeill A, 2013. Influence of organic matter, clay mineralogy and pH on the effects of CROSS on soil structure is related to the zeta potential of the dispersed clay. Soil Research 51: 34-40.
Mullins CE and Panayiotopoulos KP, 1984. The strength of unsaturated mixtures of sand and kaolin and the concept of effective stress. Journal of Soil Science 35: 459–468.
Rahimi H, Pazira E and Tajik F, 2000. Effect of soil organic matter, electrical conductivity and sodium adsorption ratio on tensile strength of aggregates. Soil and Tillage Research 54: 145-153.
Rengasamy P, 2010. Soil processes affecting crop production in salt-affected soils. Functional Plant Biology. 37: 613–620.
Rengasamy P and Marchuk A, 2011. Cation ratio of soil structural stability (CROSS). Soil Research 49: 280–285.
Rengasamy P and Sumner ME, 1998. Processes involved in sodic behaviour. Pp. 35–50. In: Sumner, ME and Naidu, R (Eds).  Sodic Soils: Distribution, Properties, Management, and Environmental Consequences. (Oxford University Press: New York)
Richards LA, 1954. Diagnosis and Improvement of Saline and Alkali Soils. USDA Hand book. 60-84.
Sparks DL, Fendorf SE, Zhang PC and Tang L, 1992. Kinetics and mechanisms of environmentally important reactions on soil colloidal surface, NATO Advanced Study Institute on Migration and Fate of Pollutants in Soils and Subsoils, Maratea, Italy, May 24-June 5.
Utomo WH and Dexter AR, 1981a. Soil friability. Journal of Soil Science 32: 203-213.
Utomo WH and Dexter AR, 1981b. Tilth mellowing. Journal of Soil Science 32: 187-201.
Watts CW and Dexter AR, 1998. Soil friability: theory, measurement and the effects of management and organic carbon content. European Journal of Soil Science 49: 73-84.
Water and Soil Science
Volume 26, Issue 3 - Serial Number 3
December 2016
Pages 161-174

Files

Share

How to cite

Statistics