Impact of reclaimed water irrigation on soil salinity, hydraulic conductivity, cation exchange capacity and macro-nutrients

Field studies were conducted at Agriculture Research Center, Oman during the year 2010/2011 to monitor the impact of reclaimed water irrigation on soil physical and chemical properties after wheat, cowpea and maize cultivation (in rotation). Three different water sources (Groundwater (GW), desalinized water (DW), and Reclaimed Water (RW)) were used as the treatments in Randomized Completely Block Design (RCBD) with 3 blocks (replicates). Samples were taken from four depths (30, 45, 60 and 90 cm) after harvesting time of the three crops. Soil salinity (ECe) in all soil depths decreased with time. Organic carbon did not show significant difference between harvest timings of wheat and cowpea. Organic carbon increased with time in soil irrigated with reclaimed water. The saturated hydraulic conductivity of the soil, Ksat didn’t show significant difference among the water types and their interaction with soil depths. Total nitrogen was the highest after cowpea harvest in reclaimed water irrigation. The soil phosphorus and potassium were not affected by any of the three water irrigation types. The highest concentrations of phosphorus and potassium were found to be in the upper soil layers. Overall, no adverse impacts of reclaimed water irrigation were observed after growing three crops of rotation.