Five profiles were selected to represent five locations of El-Gabal El-Asfar region irrigated with sewage water for five different periods, namely 0, 5, 10, 20 and 30 years. The soils of these locations known initially as salt-affected. Samples were taken from different layers of the investigated profiles to evaluate some chemical properties of the studied soils as well as their status of the fertilizer elements and the heavy metallic ions. The results obtained revealed that continuous applications of sewage water was, generally, associated with increase the soil content of organic matter as well as the cation exchange capacity, exchangeable cations, soluble nitrogen, available content of phosphorous, potassium and heavy metals. On the other hand, the values estimated for soil reaction, electrical conductivity, of soil paste extracts as well as the soluble cations and inions were reduced. The concentrations of studied heavy metals increased and in spite of this increase soil content of the lead ions remained within the normal range, however it is advisable that soil content of this hazardous metallic ions should be evaluated periodically to avoid the increase of such elements to or beyond the critical levels which may cause hazards to animals and human health. Such results give a good impression about the possibility of using sewage water for irrigation, leaching salts out and the improvement of some chemical properties of such sandy soils.
|
