Performance of Aquaculture Effluent for Tomato Production in Outdoor Raised Beds

Abstract

Raised bed production trials were conducted to evaluate the effectiveness of effluent from a biofloc-style recirculating aquaculture system producing nile tilapia (Oreochromis niloticus) as nutrient-rich irrigation water for fall ‘Celebrity’ tomato (Solanum lycopersicum) production. The objective of this study was to provide baseline vegetable production data and justification for using aquaculture effluent as a water and nutrient resource. The experiment was a split-plot, randomized block design with three treatments: aquaculture effluent, granular fertilizer, and fertigation. Tomato seeds were sown in June, transplanted in August, and grown until Oct. 2019 in nine replicated raised beds. Conventional field tomato production practices were followed throughout the trial, and data were collected for tomato fruit yield, market quality, size, leaf greenness (SPAD), and foliar nutrient analysis. Fruit yield was similar between fertigated and aquaculture effluent treatments, with granular fertilizer resulting in yield that was significantly lower (P ≤ 0.033). SPAD measurements were similar among treatments. All nutrients met or exceeded sufficiency ranges. Foliar nutrient analysis revealed no significant difference for nitrogen, phosphorus, potassium, magnesium, calcium, boron, zinc, manganese, and iron among treatments. Sulfur and copper levels were significantly lower (P < 0.05) with aquaculture effluent treatment as compared with the granular and fertigated treatments. Overall, tomato production using aquaculture effluent as a water and nutrient supplement produced similar yields to commercial practices, making it potentially viable for producers.