Soil irrigation using treated wastewater in the Brazilian semiarid region is a promising practice as this area currently faces water scarcity and pollution of water resources by domestic sewage. The aim of this study was to evaluate the use of treated wastewater in drip irrigation and its effect on the chemistry of soil cultivated with squash (Cucurbita maxima Duch.) Coroa IAC and to verify whether there was an increase in soil salinity under a semiarid climate. The experiment was conducted for 123 days on a farm close to the sewage treatment plant, in a randomized block design with five treatments and four replications. The treatments consisted of two irrigation water depths (100 and 150 % of the evapotranspiration), two applications of gypsum to attenuate wastewater sodicity (0 and 5.51 g per plant), and a control treatment with no application of wastewater or gypsum. During the experiment, treated wastewater and soil gravitational water, at a depth of 0.40 m, were collected for measurement of Na Besides an increase in pH and a reduction in total N, the irrigation with wastewater reduces soil salinity of the naturally salt-rich soils of the semiarid climate. It also led to soil sodification, in spite of the added gypsum, which indicates that irrigation with wastewater might require the addition of greater quantities of gypsum to prevent physical degradation of the soil.

RESUMOObjetivou-se, neste trabalho, avaliar a produção de moranga (Cucurbita maxima Duch. Cv Coroa IAC) irrigada com esgoto doméstico tratado. O delineamento experimental foi em blocos casualizados com cinco tratamentos e quatro repetições. Os tratamentos se constituíram de : T 1 -irrigação com lâmina de 150% da demanda hídrica da cultura; T 2 -irrigação com lâmina de 150% + adição de CaSO 4 no solo; T 3 -irrigação com lâmina de 100% da demanda hídrica da cultura; T 4 -irrigação com lâmina de 100% + adição de CaSO 4 no solo e T 5 -tratamento testemunha (sem irrigação). Foram avaliados a produtividade da cultura, o peso e o número de frutos, suas características físico-químicas (pH, acidez total, sólidos solúveis, açúcares totais, açúcares redutores e açúcares não redutores) e potencial de contaminação por agentes patogênicos na água. Foi identificada diferença significativa entre o tratamento testemunha e os demais tratamentos em relação à produção, produtividade e número de frutos. As características físico-químicas apresentaram valores similares em todos os tratamentos. Foi registrada a presença de coliformes termo tolerantes somente na superfície externa dos frutos porém em níveis abaixo dos padrões mínimos estabelecidos pelas normas sanitárias.Palavras-chave: reúso de água, irrigação, produtividade agrícola, aspectos sanitários Pumpkin yield irrigated with treated domestic wastewater ABSTRACT The objective of this study was to evaluate the yield of pumpkin (Cucurbita maxima Duch. Coroa IAC) irrigated with treated domestic wastewater. The study was conducted in a completely randomized design with five treatments and four replications. The treatments were: T 1 -irrigation depth of 150% of crop water demand; T 2 -irrigation depth of 150% of crop water demand with application of CaSO 4 in soil; T 3 -irrigation depth of 100% of crop water demand; T 4 -irrigation depth of 100% of crop water demand with application of CaSO 4 in soil and T 5 -control (without irrigation). The parameters evaluated were: crop yield, weight and number of fruits, their physico-chemical characteristics and potential contamination by pathogens in water. Significant differences in productivity, yield and number of fruits were identified between the control and all other treatments. The physico-chemical characteristics were similar in all treatments. Thermo tolerant coliforms were detected only on the surface of the fruit, but at levels below the minimum standards established by the sanitary legislation.