Early production of strawberry in aquaponic systems using commercial hydroponic bands

Abstract

Aquaponics is emerging as an interesting alternative for sustainable agriculture which meets the philosophy of circular economy, decreasing not only the need of external resources but also increasing their use efficiency. Several studies can be found dealing with the analysis of different fish species combined with a great variety of crops in systems with diverse sophistication levels. Strawberry crop may be interesting for aquaponics systems. However, early production and the quality of the fruit, which are crucial factors affecting crop profitability, have not been previously assessed in aquaponics systems. This work aimed at evaluating these factors together with the consumption of resources in strawberry production using commercial multi-layer NFT channels coupled with tench production in an aquaponic system. Production of tench with low density of fish (700–1300 g m−3) was associated to 2 hydroponic lines where plants were transplanted in rockwool plugs or bare roots. Despite the fact that the transplanting of the strawberries was performed one month later than usual for this crop, the extra-early production was 31.9 and 33.6 g per plant for rockwool and bare root substrates, respectively. No significant differences were found neither in strawberry production nor in fruit quality for the two types of substrates studied. However, parameters related to earliness varied differently along time between bare root and rockwool. The cultivation of bare root plants is recommended, since it involves lower costs by saving in the acquisition of the substrate and less environmental and health problems for workers. Despite the fact that tench is a species very well adapted to the weather conditions in the production area, its low average daily gain ratios and its long growth cycle makes it unsuitable for combination with the cultivation of strawberry. However, the combination of a joint production of fish and plants in simple aquaponic systems would allow savings in fertilizer and water, within a production framework of circular economy.