Using Treated Wastewater For Irrigating Forage Sorghum (Sorghum Bicolor) In Khartoum State

Abstract

Recycling of wastewater has emerged as a realistic option to overcome problems related to water shortages and its adverse environmental impacts. Wastewater reuse could free huge amounts of fresh water currently used for irrigation and make this resource available to meet the growing needs for fresh water for domestic uses. The present study is an attempt to evaluate the reuse of treated wastewater for irrigation under Khartoum state conditions. The experiment involved comparing the effects of three types of water viz: treated wastewater (W1), alternating treated wastewater with River Nile water (W2) and River Nile Water (W3), using three different tillage operations, harrowing (T1), disc ploughing (T2) and chisel ploughing (T3). Replicated soil samples were taken from three depths D1 (0-20 cm), D2 (20-40 cm) and D3 (40-60 cm). Forage crop (Sorghum bicolor, locally known as \\\\\\\'Abu Sabain\\\\\\\') was used as the indicator plant. The parameters measured include soil properties, plant growth & yield attributes minerals transfer factor and quality of the forage as animal feed. The treated wastewater was analyzed with reference to international (FAO) standard for irrigation water. W1 constituents were found to conform to FAO and Jordon standards for irrigation water. However, the bicarbonate (HCO3-) is in the severe restriction zone according to FAO standard. W1 significantly (P< 0.05) increases Ec, pH, OC, N, Na, Ca, Mg, K, Cl, Cu, Zn, Fe, Mn, Pb, Co and P in soil, followed by W2 and W3, respectively. On the other hand plant growth parameters, plant yield and concentrations of Na, Ca, Mg, K, N, Cu, Zn, Fe, Mn, Pb, Co and P in plant tissues were significantly (P< 0.05) increased with W1 followed by W2 and W3, respectively. Tillage operations and depths showed significant (P< 0.05) effects on the distribution and concentration of trace elements and nutrients in soil and plant tissues. The study showed that there was no significant (P< 0.05) difference between water treatments in transferring the elements from soil to plant. Of these Ca (0.77) and Co (0.74) registered higher transfer factor (TF) followed by P (0.47), K (0.36), Cu (0.34), Zn (0.28), Pb (0.21), Fe (0.16), Mn (0.12) and Na (0.11), respectively. The forage produced by W1 was found to comply with the standards of the American National Academy of Sciences, for domestic animal feed.