|Levy, G - VOLCANI CENTER|
|Huang, Chi Hua|
Submitted to: International Soil Conservation Organization Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: March 20, 2006
Publication Date: May 14, 2006
Citation: Mamedov, A., Levy, G.J., Huang, C., Norton, L.D. 2006. Effect of salinity, sodicity and soil texture on aggregate stability of semi-arid soils. In: Proceedings of the 14th conference on International Soil Conservation Organization (ISCO 2006). Water Management and Soil Conservation in Semi-arid Environments. May 14-19, 2006, Marrakech, Morocco. p. 5. 2006 CDROM. Technical Abstract: Breakdown of soil aggregates results in pore collapse which reduces infiltration rate, leads to runoff and erosion, and subsequently may cause soil degradation. Soil texture, exchangeable sodium percentage (ESP) and electrolyte concentration (EC) of the soil solution (water quality) play a significant role in determining soil physical/hydraulic properties and the response of soil clays to dispersion and swelling. This is particularly important in areas where the fresh water resources are short in supply and where effluent or saline-sodic or low quality water are used for irrigation. We studied aggregate slaking from 60 samples of Israeli top soils varying in clay content (10-70%), and ESP levels (1-30), using the high-energy-moisture-characteristics method. Two salinity levels were studied, dionized water (DW) and saline water (SW, EC=20 mmolc L-1) to simulate the effect of rain and effluent/saline irrigation water on aggregate stability. Susceptibility of aggregates of semi-arid Israeli soils to slaking decreased with (i) the increase in clay content (ii) the increase in the EC of the soil solution, and (iii) the decrease in ESP. Aggregate slaking decreased with the increase in soil clay content. In soils having inherently low aggregate stability (clay<25%) the use of SW was effective in decreasing aggregate slaking at a low level of sodicity, ESP<5. For inherently stable soils (clay>35%), aggregate slaking decreased upon use of SW only when ESP>15. A statistically significant (P<0.05) triple interaction among ESP, EC and clay content in their effect on aggregate slaking (and stability) was found, suggesting that the combined effects of these variables were complex. Therefore, whenever aggregate stability is used to predict soil structural stability or erodibility parameters, the effects of water quality, sodicty and soil texture on aggregate breakdown should not be considered independently but simultaneously. The relationship between aggregate stability, drainable porosity and salinity (water quality), sodicity (ESP) and soil texture is discussed in this paper.