60 JUNE 2022 • WORLD AQUACULTURE • WWW.WA S .ORG Experiment with FrenchMarigold Algae pellets are sold as growth and flowering enhancers to supplement normal fertilization of flowering plants. The second experiment assessed the effects of microalgal treatments on growth and flowering parameters of French marigold Tagetes patula L (Fig. 2). Marigolds were grown from seeds in a peat moss and soil bed. Two-week old seedlings were individually transplanted to 3-L pots filled with air-dried soil and peat moss at a ratio of 1:1. Fifteen replicate pots were assigned to each of the ten treatments, distributed in the greenhouse in a completely randomized design. Irrigation regimen was 0.1 L per event per pot three times a week, calculated based on the water holding capacity of the soil to avoid deep percolation. Half (75) of the pots were labeled with these treatment designations: DW (distilled water), T1 (green aquaculture water), T2 (supernatant), T3 (wet microalgae) and T4 (mineralized microalgae) and treated as described for the radish experiment. Another half were labelled T5 T6, T7, T8 and T9 and treated as the first half of the pots but were also fertilized once with a commercial liquid fertilizer at the recommended dose on the day the plants were transplanted to the pots. These were then treated similar to the other five treatments where T5 was similar to DW, T6 to T1, T7 to T2, etc. Treatments were applied to the pots for ten irrigation events and then irrigated with de-chlorinated tap water for the remainder of the nine-week growing period. At study termination, all marigold plants were cut at the base of the shoot 1 cm above the soil surface. Shoot height, flower count, TABLE 2. Response of French marigold to various treatments of fertilizer and aquaculture effluent combinations. Treatment Fresh Fresh Fresh F lower Shoot Dr y Dr y Dr y shoot f lower above - count he ight shoot f lower above - we ight we ight ground (cm) we ight we ight ground (g /plant) (g /plant) biomas s (g /plant) (g /plant) biomas s (g /plant) (g /plant) DW 1.7c 0.6c 2.2c 1.3c 12.8c 0.31c 0.1cc 0.40c T1 3.4a 2.0a 5.4a 2.8a 17.0a 0.61a 0.34a 0.95a T2 3.2a 1.9a 5.1a 2.6a 15.5a 0.56a 0.32a 0.88a T3 3.7a 1.9a 5.6a 2.6a 15.3a 0.59a 0.31a 0.90a T4 3.0a 1.6a 4.5a 2.6a 16.1a 0.53a 0.26ac 0.77a T5 6.3b 2.4 8.7b 3.3b 17.5b 1.21b 0.62b 1.83b T6 6.3b 2.9b 9.2b 3.9b 18.2b 1.04b 0.75bb 1.79b T7 6.1b 3.0b 9.1bb 4.7b 17.9b 1.06b 0.70b 1.76b T8 6.7bb 2.8b 9.45b 3.9b 17.4b 1.14b 0.54bb 1.68b T9 5.71b 2.55b 8.26b 3.9b 17.5b 1.04b 0.46b 1.50b PSE 0.84 0.37 1.07 0.5 0.71 0.13 0.12 0.2 Note: Values with different superscript in each column are significantly different from each other p < 0.05 (n=15); SW is shoot weight, FW is flower weight. PSE is Pooled Standard Error. DW, control; T1, green aquaculture water; T2, aqueous extract; T3, microalgae; T4, mineralized algae; T5, fertilizer; T6, fertilizer + green aquaculture water; T7, fertilizer + aqueous extract; T8, fertilizer + microalgae; T9, fertilizer + mineralized microalgae. TABLE 1. Response of radish plants to various microalgae treatments. Treatment Fresh root Fresh shoot Fresh shoot Dry root Dry root Dry total weight (g/plant) weight (g/plant) biomass (g/plant) weight (g/plant) weight (g/plant) biomass (g/plant) DW 1.5b 2.8b 4.3b 0.10c 0.29b 0.39b T1 2.9a 4.6a 7.5a 0.18b 0.45a 0.62a T2 2.5a 5.1a 7.7a 0.16b 0.45a 0.61a T3 2.5a 4.6a 7.1a 0.21ab 0.42a 0.62a T4 2.8a 4.7a 7.5a 0.21a 0.43a 0.64a PSE 0.23 0.43 0.64 0.02 0.04 0.06 Note: Values with different superscript in each column are significantly different from each other p < 0.05 (n = 27). DW is distilled water; T1, green aquaculture freshwater; T2, supernatant aqueous extract; T3, wet microalgae; T4, mineralized microalgae; PSE, Pooled Standard Error.
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