Evaluation of the Development and Nutritional Quality of Halophytes Cultivated with Saline Water from Different Aquaculture SystemsAuthor: Larissa Midori Konishi Britz (Currículo Lattes)
Advisor: Dr. Cesar Serra Bonifácio Costa
Abstract
In addition to enhancing food and water security, the cultivation of vegetables using nutrient-rich sources such as saline aquaculture water is a sustainable alternative capable of generating additional income for producers. For plant production under saline water conditions, halophytes—plants adapted to high concentrations of Na⁺ and Cl⁻ ions—are required. This study evaluated the production and nutritional quality of the halophytes Apium graveolens (var. Tall Utah) (commonly known as celery) and Salicornia neei (progeny BTH2) (sea asparagus) under different saline cultivation conditions. Initially, both halophytes were grown in aquaponics (hydroponics using aquaculture water) integrated with the cultivation of the coastal fish miragaia (Pogonias courbina) under clear water and Biofloc Technology (BFT), the latter characterized by high total suspended solids (TSS) and resulting in the "flocponic" cultivation of plants. Additionally, A. graveolens and S. neei were cultivated in beds with different planting densities, irrigated with saline water from an extensive Pacific white shrimp (Penaeus vannamei) farming system. The first experiment took place on floating rafts inside juvenile miragaia tanks with two treatments: BFT and clear water systems (both with salinity of 10 g L⁻¹ and in triplicate). After eight weeks, celery was harvested and its average stem weights were evaluated at 22.30 ± 0.85 g and 0.83 ± 0.06 g, respectively, in aquaponics with and without bioflocs. The performance of sea asparagus was assessed through pruning and quantification of stem regrowth. After six weeks, average stem weights were 45.94 ± 2.04 g and 8.35 ± 0.42 g, respectively, in aquaponics with and without bioflocs. Salicornia neei (0.64 kg m⁻² 30 days⁻¹) and A. graveolens (0.23 kg m⁻² 30 days⁻¹) also achieved higher mean stem biomass productivities in floating raft systems under BFT. There was no difference in the growth of P. courbina juveniles between treatments. The second experiment occurred in beds with eutrophic solodic haplic Planosol and surface irrigation (420 L day⁻¹, average salinity of 21.9 ± 0.8 g L⁻¹), under planting density treatments of 13 and 25 ind. m⁻². All A. graveolens plants died within three weeks of planting. The average stem biomass of S. neei, regrown 28 days after leveling pruning, was 0.85 kg m⁻², with no significant differences between planting densities. However, better agronomic parameters (individual stem biomass and number of branches >10 cm) were observed at lower planting density and in moister soil in the lower area of the cultivation field. Salicornia neei proved to be a good alternative for aquaponic production of plant biomass on floating rafts coupled with P. courbina cultivation in BFT systems, as well as for soils irrigated with saline water from extensive shrimp farming. Apium graveolens showed good growth and productivity in BFT systems with 10 g L⁻¹ salinity, but was unable to develop in more saline soils (≈ 20 g L⁻¹) and high summer temperatures in southern Brazil (average 25 °C). Moisture, lipid, protein, and mineral contents in halophyte stems were little influenced by aquaponic conditions (clear water vs. bioflocs). Ash and crude protein values in S. neei stems were higher in field-grown plants compared to aquaponics, likely due to the higher salinity in the field experiment.