PEDOLOGICAL CHANGES OF THE NILE DELTA SOILS AS AFFECTED BY THE TILE DRAINAGE

Abstract

Agricultural lands in Egypt had been brought under perennial irrigation after the construction of Aswan High Dam (1960-1968). The natural drainage system that had sustained permanent agriculture for millenium cou ld no longer cope with increased percolation from irrigation, and large areas had become water logged and salinized. In nowadays, soil salini zation constitutes a major threat to irrigate? agriculture, in the Nile delta soils. It is generally hypothesized that salinization is caused by (i) capillary rise from a saline ground water table and (ii) concentration of salts in the field due to lack of adequate drainage system. It had been reported that drainage is needed to provide an aerated zone for crops and to prevent or correct salinity problems associated with high water tables.

At the end of 1998 an area of about 2.209 million feddans in the Nile delta was provided with tile drainage. The current program for land dra inage in Egypt up to year 2000, consists of another 3.8. million feddans should be covered by tile drainage to become 5,1 1 5,000 feddans. Execution of the tile dra inage had been carried out at different stages. The adopted techniques had been modified according to the development of materials used and to the accumulation of available knowledge. It has become serious to examine and evaluate the efficiency of the di fferent dra inage systems executed along the di fferent stages (Amer and Abu­ Zaid, 1989).

Morphology and micromorphology have become important branches m soil sciences, where the data obtained could be used to predict certain aspects of soil hydrologica l and physical behaviour. However, morphology and micromorphology were used to realize the objective of the current stud y.

Chemical, physical and biological soil properties are highly related to the prevailed drainage condition, which could be considered as good reflection to the efficiency of the excuted dra inage system.