DRAINAGE WATER QUALITY AND ITS EFFECTS ON SOIL PROPERTIES AND CHEMICAL COMPOSITION OF PLANTS

The present study was carried out on Meraga drain located in EL-Gamalia district, Dakahlia Governorate(Middle Nile Delta) to evaluate the effect  of drainage water quality on soil properties and chemical composition of plants. Meraga drain passes many villages dotted along it receiving their agriculutral drainage water, house waste waters  and industrial effluents. Water  samples were seasonally collected from 6 sites  along this drain ( EL-Gamalia city (0),1.5, 3.0, 4.5, 6 and 7.5 km.). Water samples were seasonally collected during June 2009 to March 2011. Also, soil samples and plant were collected seasonally from the distance  of 1.5 to 6 km.
The main obtained results are presented as follows:

Electrical Conductivity (EC) values increased slightly with northward direction. Also, Sodium Absorption Ratio (SAR) took the same trend, the quality of studied drainage water belong to  C3 S1 and C4 S1 classes and could be re-use  in irrigation purpose under special management.
Boron (B) concentration, at most of locations  have low concentration (B1) < 3 mg L^-1 which less than the critical limit indicating (slight to moderate for restriction on use).
Nitrate –N concentrations was ranged from 5-30 ppm in the Meraga drains in two summer seasonally 2009 and 2010 whereas, the  other seasonally was higher than the critical limits.
Micronutrients and heavy metal ions concentrations (Fe⁺², Mn²⁺, Zn²⁺ Pb²⁺) were less than permissible levelsat all selected water samples.
Using drainage water for irrigation, caused an increase in soil content of available micronutrients (Fe, Mn and Zn) whereas, heavy metals (Pb) was less than the permissible limits (500 mg kg^-1).
Concentrations of heavy metal  and micronutrients (Fe, Mn, Zn and Pb) in straw and grains of wheat and rice grown in the most locations were under the permissible limits except Pb and Fe concentration exceeds the critical levels in all locations.The concentration in straw of wheat and rice crops were higher than in the grain at all location.
Zn and Mn concentrations were less than critical limits at all locations in shoot of clover plants and Pb and Fe concentrations were higher than critical limit  at all locations.
 Finally, the rice crop had better effect on water quality than cotton then wheat and finally clover.