The effect of reusing treated wastewater in irrigation on some chemical soil properties and wheat crop growth

Abstract

This study was aimed to investigate the suitability of reusing of treated wastewater to irrigate wheat crop and its impact on soil properties. The study was conducted during the Agricultural season 2014-2015, at Sirte, Libya. The climate of this area characterized by dry and hot in summer, cool and rained in winter, as well as the annual rainfall in the range of 175 mm to 200 mm, so the area is considered as semi-arid area. The experiment was designed to use treated wastewater under different managements ((W1) 100% fresh water (from artificial stream), (W2) Mixed by 50% fresh water and treated wastewater, (W3) mixed by 33% fresh water and 67% treated wastewater and (W4) 100% treated wastewater). Two soil profiles were selected and described, namely Sandy (S1) and Sandy loam (S2) soils. Wheat crop was used as indicator. The chemical, physical and microbiological analyses were done for water and soil samples using standard methods. The analyses include soil texture, bulk density, moisture content, electrical conductivity, pH, anions, cations, and E coli form. Also, the wheat crop growth components were studied. The quality of used water was found within the permissible levels of the Food and Agricultural Organization of the United Nation (FAO) for irrigation water, while lead was found exceeding the sever permissible level. From the other hand treated wastewater showed significant difference at P≤0.05 in increasing the average values of wheat crop growth components, in compare with fresh water, which recorded the lowest values. The chemical properties of soils extractions showed non -significant difference at P≤0.05 under the different irrigation managements, while the chloride and lead showed significant increase in sand loamy soil and carbonate in sandy soil. On the other hand, the both soils showed the same performance in increasing wheat growth components. The treated wastewater (W4) supplied significant numbers of E coli form 100/ml to the both soils followed by (W3), while fresh water recorded less values. The study concluded that using of treated wastewater in irrigation of agricultural crops under monitoring system has economic feasibility.