Esgoto doméstico tratado como fonte de água e nutrientes no cultivo em substrato do morangueiro

Abstract

The disproportionate distribution of natural resources and the demand for water and nutrients in agricultural systems make it important to search for alternative sources for irrigation. Thus, a mitigating measure that has been disseminated is the use of treated domestic sewage in agriculture, in addition to providing water for agricultural crops, can ensure increased production due to the contribution of nutrients and organic matter. Thus, the objective of this work was to evaluate the feasibility of the cultivation technique, productivity and quality of strawberries (Fragaria x ananassa Duch) San Andréas obtained in cultivation with substrate, using solution from treated domestic sewage with and without the addition of mineral fertilizers. The experiment was conducted in an agricultural greenhouse, in which strawberry plants were grown in a system with Styrofoam troughs filled with coconut fiber substrate. The three types of treatments: (TA) drinking water plus mineral fertilizers, (TRA) treated domestic sewage supplemented with mineral fertilizers, and (TR) treated domestic sewage only were experimentally designed in randomized block design. Quantitative results were evaluated using analysis of variance and followed by the Shapiro-Wilk test and Tukey's test at 5% significance level. The experimental results showed that the use of treated domestic sewage as the only source of water and nutrients (TR), resulted in plants with low productivity and commercial fruit quality. The productivity and quality of the fruits such as number of fruits, length, diameter, fresh mass and total soluble solids, produced with the TRA solution was statistically similar to the conventional growing system (TA), demonstrating the phytotechnical feasibility of using treated sewage water. The substrate culture technique also proved to be safe, with no reported contamination of the fruits by Escherichia coli bacteria. The use of treated domestic wastewater promoted savings of 13.1% mineral fertilizers and approximately 4500 L of drinking water during the entire cultivation cycle. With these results, it is concluded that the use of treated household wastewater as a source of water and nutrients in substrate cultivation presents feasibility in productivity and fruit quality of strawberry without compromising food safety.