Restriction of available water observed in the last years in arid or semiarid areas forces the planners to consider any source of water for irrigation. The purpose of this paper was to investigate the suitability of wastewater produced by the treatment plant of the city of Larissa, Central Greece for irrigation of corn. With a three year's field experiment it was shown that wastewater significantly increased corn yield and may substitute considerable quantities of mineral fertilizers. Increase in corn yield was attributed mainly to the increase of N uptake and secondary to the increase of P, K, B, Fe, Zn, Mn, and Cu uptake.
During the last years a severe restriction of available water for various uses was recorded especially in semiarid or arid areas. In such cases, planners are forced to consider any source of water for possible use for irrigation. One such source, is wastewater produced by the municipal wastewater treatment plants that is commonly used for irrigation of agricultural crops (Tsobanoglous and Burton, 1991). From the other hand, wastewater contains considerable amounts of nutrients such as N and P that can substitute proportional quantities of mineral fertilizers. In Greece during the last years wastewater treatment plants were established in many cities, even the small ones, producing considerable quantities of treated wastewater, that must be managed in a sound way from both economical and environmental viewpoints. Research related to the use of wastewater for irrigation and its impacts is limited. So, the purpose of the present study was to investigate the suitability of wastewater produced by the treatment plant of the city of Larissa, Central Greece, for irrigation of corn and as partial substitution of mineral fertilizers.