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Soil structure changes: Aggregate size and soil texture effects on hydraulic conductivity under different saline and sodic conditions
Year:
2009
Authors :
בן-חור, מני
;
.
Volume :
47
Co-Authors:
Ben-Hur, M., Institute of Soil, Water and Environmental Sciences, Volcani Center, Agricultural Research Organization, PO Box 6, Bet Dagan 50250, Israel
Yolcu, G., Menemen Research Institute of Rural Services, Menemen, Izmir, Turkey
Uysal, H., Faculty of Agriculture, University of EGE, Izmir, Turkey
Lado, M., Faculty of Sciences, University of A Coruna, A Zapateira s/n, 15071 A Coruna, Spain
Paz, A., Faculty of Sciences, University of A Coruna, A Zapateira s/n, 15071 A Coruna, Spain
Facilitators :
From page:
688
To page:
696
(
Total pages:
9
)
Abstract:
Hydraulic conductivity of soil is strongly dependent on soil structure, which can be degraded during wetting and leaching. It was hypothesised that this structural degradation is dependent on initial aggregate size distribution and soil texture. The general aim of this study was to investigate the effects of aggregate sizes and soil textures, and their interactions, on the structural degradation and saturated hydraulic conductivity (Ks) of smectitic soils under different saline and sodic conditions. The studied soils were clay and loamy sand soils with low (∼4.5) or high (∼10) exchangeable sodium percentages (ESP), and with aggregate sizes in the ranges: (i) <1mm (small aggregates); or (ii) 24mm (large aggregates). The Ks values of the samples in a column after slow or fast pre-wetting were determined by means of a constant head device. Different wetting rates and leaching under various saline and sodic conditions had no effect on the Ks of the loamy sand; however, the Ks values of this soil with large aggregates were an order of magnitude greater than those of the soil with small aggregates. In contrast, in the clay soil with large aggregates, the Ks values after fast pre-wetting were significantly smaller than those after slow pre-wetting, probably because of aggregate slaking. No significant effects of the wetting rates on Ks were found in clay soil with small aggregates. An increase in the ESP in the clay soil decreased the Ks by a factor of 1.5 for the large aggregates and by an order of magnitude for the small aggregates, mainly as a result of increased clay swelling. Leaching the clay soil with deionised water significantly decreased the Ks values, partly because of clay dispersion. Although significant structural degradation of the clay soil occurred during leaching, the Ks values were smaller in the soils with small aggregates than in those with large aggregates, indicating the importance of the initial aggregate size on Ks even in soils that are prone to structural damage. © 2009 CSIRO.
Note:
Related Files :
Aggregate size distributions
Clay dispersion
Clay minerals
Deionized water
Flashover
Order of magnitude
Pre-wetting
Textures
עוד תגיות
תוכן קשור
More details
DOI :
10.1071/SR09009
Article number:
Affiliations:
Database:
סקופוס
Publication Type:
מאמר
;
.
Language:
אנגלית
Editors' remarks:
ID:
23552
Last updated date:
02/03/2022 17:27
Creation date:
17/04/2018 00:00
Scientific Publication
Soil structure changes: Aggregate size and soil texture effects on hydraulic conductivity under different saline and sodic conditions
47
Ben-Hur, M., Institute of Soil, Water and Environmental Sciences, Volcani Center, Agricultural Research Organization, PO Box 6, Bet Dagan 50250, Israel
Yolcu, G., Menemen Research Institute of Rural Services, Menemen, Izmir, Turkey
Uysal, H., Faculty of Agriculture, University of EGE, Izmir, Turkey
Lado, M., Faculty of Sciences, University of A Coruna, A Zapateira s/n, 15071 A Coruna, Spain
Paz, A., Faculty of Sciences, University of A Coruna, A Zapateira s/n, 15071 A Coruna, Spain
Soil structure changes: Aggregate size and soil texture effects on hydraulic conductivity under different saline and sodic conditions
Hydraulic conductivity of soil is strongly dependent on soil structure, which can be degraded during wetting and leaching. It was hypothesised that this structural degradation is dependent on initial aggregate size distribution and soil texture. The general aim of this study was to investigate the effects of aggregate sizes and soil textures, and their interactions, on the structural degradation and saturated hydraulic conductivity (Ks) of smectitic soils under different saline and sodic conditions. The studied soils were clay and loamy sand soils with low (∼4.5) or high (∼10) exchangeable sodium percentages (ESP), and with aggregate sizes in the ranges: (i) <1mm (small aggregates); or (ii) 24mm (large aggregates). The Ks values of the samples in a column after slow or fast pre-wetting were determined by means of a constant head device. Different wetting rates and leaching under various saline and sodic conditions had no effect on the Ks of the loamy sand; however, the Ks values of this soil with large aggregates were an order of magnitude greater than those of the soil with small aggregates. In contrast, in the clay soil with large aggregates, the Ks values after fast pre-wetting were significantly smaller than those after slow pre-wetting, probably because of aggregate slaking. No significant effects of the wetting rates on Ks were found in clay soil with small aggregates. An increase in the ESP in the clay soil decreased the Ks by a factor of 1.5 for the large aggregates and by an order of magnitude for the small aggregates, mainly as a result of increased clay swelling. Leaching the clay soil with deionised water significantly decreased the Ks values, partly because of clay dispersion. Although significant structural degradation of the clay soil occurred during leaching, the Ks values were smaller in the soils with small aggregates than in those with large aggregates, indicating the importance of the initial aggregate size on Ks even in soils that are prone to structural damage. © 2009 CSIRO.
Scientific Publication
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