HIGHLIGHTS:
Fish farming effluent is a viable alternative for use in hydroponic watercress cultivation.
Integrated production between aquaculture and hydroponic vegetable can increase water use efficiency.
The use of effluent from fish farming reduces the use of nutrient solution in NFT hydroponic system.
ABSTRACT
Aiming at a more sustainable food production, the reuse of effluent from fish farming in hydroponics can be a viable option. Thus, the objective of present study was to evaluate the effects of the use of effluent from fish farming on the development of ‘Folha Larga’ watercress and the possibility of reducing the use of fertilizer in a hydroponic system. The assay was carried out in a greenhouse from October 2021 to February 2022 (two cycles). The treatments were distributed in randomized blocks, with four replications, with split plots, consisting of two times of recirculation of the solution in the plots (T1 = 15 min operating by 15 min off and T2 = 15 min operating by 30 min off) and five solutions, in the subplots, obtained by mixing different proportions (0, 25, 50, 75, and 100%) of nutrient solution and effluent from fish farming. The variables analyzed were: plant height, number of leaflets, leaf area, SPAD index, fresh and dry weight of the aerial part and roots. The use of effluent from fish farming reduces the amount of fertilizers for the yield of ‘Folha Larga’ watercress. Nutrient solution recirculation time of 15 minutes is suitable for hydroponic watercress.
Key words:
Nasturtium officinale; water quality; Oreochromis niloticus
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NS 0% - 0% NS and 100% RW; NS 25% - 25% NS and 75% RW; NS 50% - 50% NS and 50% RW; NS 75% - 75% NS and 25% RW; NS - 100% NS and 0% RW
** - Significant at p ≤ 0.01 by the F test. Vertical bars represent the standard deviation of the mean
** - Significant at p ≤ 0.01 by the F test. Vertical bars represent the standard deviation of the mean
** - Significant at p ≤ 0.01 by the F test. Vertical bars represent the standard deviation of the mean
S1 - 0% NS and 100% RW; S2 - 25% NS and 75% RW; S3 - 50% NS and 50% RW; S4 - 75% NS and 25% RW; S5 - 100% NS and 0% RW. T1 = 15 minutes operating at 15-minute interval and T2 = 15 minutes operating at 30-minute interval
** - Significant at p ≤ 0.01 by the F test. Vertical bars represent the standard deviation of the mean 1st and 2nd production cycles
** - Significant at p ≤ 0.01 by the F test. Vertical bars represent the standard deviation of the mean in the 1st and 2nd cycles