The use of saline aquaculture effluent for production of Enterolobium contortisiliquum seedlings.

The use of aquaculture effluent for irrigation of field crops has been suggested as the most appropriate biological method for treatment of this effluent. However, using it for irrigation of tree species in seedling nurseries might be a better alternative to avoid soil salinization and groundwater contamination in agricultural fields. This paper aimed at assessing the production of Enterolobium contortisiliquum seedlings under irrigation with saline aquaculture effluent. The experiment was carried out in a randomized complete block design with four replicates and four seedlings per experimental unit. Each replicate was daily irrigated with five solutions containing different concentrations of saline aquaculture effluent diluted with freshwater (0, 25, 50, 75 and 100% effluent). Despite increasing substrate salinity, the dilution of saline aquaculture effluent in the irrigation water promoted greater shoot growth and higher total dry weight in E. contortisiliquum. Moreover, seedlings treated with low concentrations of this effluent increased their leaf area expansion and chlorophyll content. Therefore, the use of solutions containing 25 and 50% effluent allowed the production of high-quality seedlings. These results suggest that saline aquaculture effluent can be reused to irrigate tree species, enabling a successful integration of aquaculture and agriculture and reducing environmental impacts of improper effluent disposal.