Evaluation of Using Treated Wastewater on Soil Chemical Properties and Crop Productivity in Gaza Strip

Abstract

The increasing demand for water in the arid and semi-arid regions has resulted in the emergence of wastewater application for agriculture. Using treated wastewater as marginal quality water in agriculture is a justified practice, yet care should be taken to minimize adverse environmental impacts and to prevent soil deterioration. The objective of this research is to investigate the impact of using treated wastewater for irrigation on soil chemical properties and plant productivity. An reuse pilot study was carried out in Al-Zaitoun agricultural farm in the Gaza Strip from May to September2011. Acomparison was carried out between the soil properties in two experimental plots; one was irrigated with the effluent from Gaza Wastewater Treatment Plant over a period of four months, and the other was irrigated with fresh water in the same period. The irrigation water was applied by drip irrigation system, and the crop used was sorghum. The fresh water samples were obtained from the local well in the farm, and treated wastewater samples were obtained from the wastewater collection basin and analyzed for TSS, EC, pH, TDS, Ca, Mg, Na, SAR, CO3, Cl, NO3, TKN, TP, K, PO4, and selected heavy metals "Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn" in addition to BOD, COD and the number of fecal and total coliforms before irrigation. Composite soil samples were taken from depth of 0-30 cm in both plots and analyzed for the main chemical parameters. The results indicated that the level of TDS, Na, Cl, TSS, Zn and Fe were higher in the effluent than the fresh water; it was above the recommended Palestinian standard for dry fodder irrigated by treated wastewater. Also, irrigation with wastewater lead to significant increase in O.M, CEC, K, TP, Ca, Mg, Na, and Cl in soil than irrigation with fresh water. In addition, the increases of Zn, Fe, Mn, and Pb in soil and sorghum plant irrigated with treated wastewater were significant in comparison with the plants irrigated with fresh water. Further, treated wastewater increased the plants height, and grain weight of sorghum.