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The third paper I will review is titled ‘Mineral Nutrient Concentration and Uptake of Tomato Irrigated with Recirculating Aquaculture Water as Influenced by Quantity of Fish Waste Products Supplied‘.
This study demonstrates that the Integrated AquaVegeculture System (iAVs) can provide sufficient nutrients for plant growth without the need for additional supplementation of base minerals.
The study found that all nutrients were assimilated above deficiency levels, with tissue concentrations of nitrogen (N), phosphorus (P), potassium (K), and magnesium (Mg) not being limiting. Although calcium (Ca) was found to be low and sulfur (S) was high when their sole nutrient source was fish waste, micronutrients were assimilated in excess of sufficiency, and toxicity was not observed. This indicates that the nutrient profile provided by the fish waste in the iAVs system is largely adequate for plant growth.
Furthermore, the study suggests that alterations in fish feed mineral nutrient content could better meet plant requirements while still remaining within the range of fish needs, rather than adding supplementary nutrients directly to the system. For example, the fish feed formulation employed in the study was found to be relatively low in calcium (Ca) for supporting plant growth, suggesting that the Ca component of the fish feed might be increased to mitigate deficiencies in tomato crops irrigated with recirculatory aquaculture water. This approach maintains the closed-loop nature of the iAVs system, leveraging adjustments in fish feed composition to balance nutrient availability for plants, rather than relying on external nutrient inputs.
In summary, the iAVs system, as evidenced by the research, does not require the usual addition of base minerals like magnesium, potassium, iron, etc., because the system inherently provides a balanced nutrient profile.