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1 Abbo, S. H. 1983. Theoretical and practical approach for the modelling of soil expansion and its interaction with structures built on expansive clay soils. In Sudan, Ministry of Irrigation, Proceedings of the Seminar on Expansive Clay Soil Problems in the Sudan, Wad Medani, 29th-31st January 1983 (pp 71-80). Wad Medani, Sudan: Ministry of Irrigation.
(Location: IWMI-PAK Call no: 631.7.2 G146 SUD Record No: H072)
2 Moustafa, A. T. A.; Tinsley, R.L. 1984. Influence of soil properties on irrigation management in Egypt. Cairo, Egypt: Egypt Water Use and Management Project. vii, 66p. (EWUP technical report no.64)
(Location: IWMI-HQ Call no: 631.7.2 G232 MOU Record No: H0034)
On three of the four distributary canals studied by EWUP, the soils were mostly alluvial clay soil (vertisols) or a vertic subgroup of the entisols. The remaining distributary canal was all sandy Entisols. Vertisols are as oil order composed of heavy, clay soils containing large quantities of clay minerals which expand when wet and contract when dry. Irrigating these soils requires recognizing that the root penetration and measurable soil water changes are restricted to the top 40 cm. This limits the operational available water to 5 to 7 cm. The water infiltration rate during an irrigation can have a hundred fold decline during a 2 hour irrigation, ending with almost sealed conditions. This allows highly uniform application over a large area almost independent of available flow rate. Soil sealing requires a potential for surface drainage to prevent crop suffocation. After an irrigation, redistribution tends to be very slow, with the possibility in winter of it requiring 15 days for a wetting fringe to drain 30 cm. The high infiltration rates in the sandy soils make them basically unsuited for surface irrigation. It is therefore difficult to surface irrigate them efficiently. High water tables occur with large volumes of subsurface water flow. A de facto sub-irrigation system results in which farmers applying water to their field sub-irrigate their neighbors and vise-versa. Some farmers, far from the water source, actually receive more water than their crops required.
3 Hameed, A. S.; Sony, C. D.; Velayudhan, K. T.; Vasu, K. 2000. Groundwater quality deterioration due to clay mining industry in a midland region of Kerala. In Mehrotra, R.; Soni, B.; Bhatia, K. K. S. (Eds.), Integrated water resources management for sustainable development - Volume 1. Roorkee, India: National Institute of Hydrology. pp.475-484.
(Location: IWMI-HQ Call no: 333.91 G000 MEH Record No: H028068)
4 Kariuki, P. C.; van der Meer, F. 2003. Issues of effectiveness in empirical methods for describing swelling soils. International Journal of Applied Earth Observation and Geoinformation, 4(3):231-241.
(Location: IWMI-HQ Call no: P 6743 Record No: H034039)
(Location: IWMI HQ Call no: 630 G000 INT Record No: H046693)
(16.90 MB) (16.9 MB)
(Location: IWMI HQ Call no: e-copy SF Record No: H049945)
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