Growth of Okra Under Nitrogen Rates and Wastewater in the Brazilian Semiarid Region

Water is one of the most important natural resources, especially for semiarid regions where it is very limited. Thus, some alternatives to preserve water are necessary. In this sense, we aimed to evaluate the effect of irrigation with post-treated domestic wastewater associated with different nitrogen rates on the growth of okra in the semiarid region of Brazil. The experiment was performed in the municipality of Pombal, state of Paraíba, Brazil. It was used a randomized block design with six nitrogen rates (N1 = 0, N2 = 40, N3 = 80, N4 = 120, N5 = 160, and N6 = 200 kg ha-1) and wastewater corresponding respectively to 0; 25; 50; 75; 100; and 125% of the fertilization recommendation for the okra crop. In addition to these treatments, a control was added and the plants received 100% of the recommended dose of nitrogen and they were irrigated with water (IW). The control was compared with the treatments that were irrigated with wastewater and received the minimum (0%) and the recommended (100%) doses of nitrogen fertilization. The use of treated wastewater is an excellent technique for the reuse of water in semiarid regions, but it does not fully meet the okra nitrogen requirements.