Economic benefit from irrigation of cotton and corn with treated wastewater

The effect of irrigation with treated municipal wastewater on the agricultural income from cotton and corn crops was studied by a three-year field experiment (1995-1997), carried out within the wastewater treatment plant (WWTP) of the city of Larissa, central Greece. The experimental design for both crops was randomised complete blocks with five treatments (M- control-irrigation with fresh water, W-irrigation with wastewater and no mineral fertilization, MF- irrigation with fresh water and complete mineral fertilization, WSF- irrigation with wastewater and reduced mineral fertilization, WTF- irrigation with wastewater and complete mineral fertilization). Each treatment was replicated four times. The agricultural income was assessed using the yield of the crops and the economic data of the area. The results showed that in the case of corn, the treatment WTF gave the highest agricultural income. The treatments W and WSF gave higher agricultural income compared to the control but was not significantly different compared to the treatment MF. In the case of cotton, all the treatments included wastewater use, increased significantly the agricultural income in comparison to the control, but at similar level as the treatment MF did. From the data of this study, it is concluded that treated wastewater can be used for irrigation of corn and cotton, saving fresh water and mineral fertilizers and obtaining the same or better economic results.