Effect of Irrigation with Sewage Effluent and Rhizobia Inoculation on Growth of Tropical Tree Legumes in Northeast Brazil

The use of domestic sewage in the agriculture is an alternative for reduction of the pollution of rivers, pres- ervation of resources hydrics and availability of water and nutritious for plants. An experiment was conducted to investigate the effects of irrigation with sewage effluent and rhizobia inoculation on growth parameters and macro and micronutrients contents in shoots of leguminous trees grown in an Alisol in northeastern Brazil. Irrigation with sewage effluent and rhizo- bium inoculation affected significantly the growth parameters and nodulation of L. leucocephala and M. caesalpiniaefolia. Statistically higher values of shoot dry matter and plant height were observed in leguminous trees irrigated with sewage effluent, compared to treatment with water irrigation.Sewage effluent irrigation treatment also increased significantly the contents of N, P, K, Ca, Mg, Fe, Zn and Mn in shoots of woody legumes studied after harvest. Inoculation with Rhizobium promoted significant increases in growth parameters and macro and micronutrients contents, only when associated with application of sewage effluent.