Germán Darío Aguado

Introduction. A comprehensive evaluation of hydroponic production systems relative to conventional approaches is essential for understanding their performance, particularly regarding resource-use efficiency and spatial intensification. Objective. To compare the spatial productivity and water use efficiency of hydroponic and soil-based Lactuca sativa L. production systems. Materials and methods. The experiment was conducted at the Instituto Nacional de Tecnología Agropecuaria, Mendoza Research Station, Luján de Cuyo, Argentina, from August to October 2025. Four production systems were compared: indoor hydroponic vertical farming with artificial lighting (A), greenhouse hydroponic vertical farming with supplemental artificial lighting (B), conventional horizontal hydroponic cultivation in a greenhouse without artificial lighting (C), and soil-based cultivation in a greenhouse (D). Each system consisted of three independent experimental units, and the data were analyzed using a linear mixed-effects model. Yield, water consumption, water productivity, water consumption per unit of horizontal area, and lettuce nutritional status were evaluated. Results. Vertical systems (A and B) achieved higher yields per unit of horizontal area than C and D, while D produced greater individual plant biomass. System A showed the highest daily productivity and the lowest water consumption per production cycle. Hydroponic systems required significantly less water per plant and per cycle than D. For water consumption per unit of surface area, A showed the lowest value, B and C showed similar intermediate values, and D the highest. Foliar nutrient concentrations and chlorophyll index differed among systems. Conclusions. Vertical systems achieved greater spatial productivity, while hydroponic systems showed lower water consumption than soil-based cultivation.

Agro-industrial activities generate significant amounts of organic waste and a variety of effluents thus posing environmental challenges. Viticulture in Argentina, which covered 204,847 ha in 2023, faces water scarcity as a limiting factor conditioning its production. This industry produces large volumes of grape marc, sediments, and stalks, which can be valorised into products like alcohol, tartaric acid, and compost. However, these valorisation processes generate effluents with high organic load and salinity, further stressing water resources. This study explores the potential of utilising these effluents to cultivate plant biomass in arid regions (sorghum or perennial pasture), which could serve as bioenergy, animal feed, or composting co-substrates, contributing to circular bioeconomy principles. The combined use of effluent as a water resource and the sowing of sorghum and pasture increased soil organic matter content and led to a slight reduction in pH (depth: 0.30–0.60 m) compared to the control treatment. The sorghum plots showed better establishment and higher dry biomass yield (32.6 Tn/ha) compared to the pasture plots (6.5 Tn/ha). Sorghum demonstrated better tolerance to saline soils and high salinity effluents, aligning with previous studies. Although pasture had a lower biomass yield, it was more efficient in nutrient uptake, concentrating more NPK, ash, and soluble salts. Sorghum’s higher yield compensated for its lower nutrient concentration. For biomass production, sorghum is preferable, but if nutrient capture from effluents is prioritised, summer polyphytic pastures are more suitable. These results suggest that the final selection between plant biomass alternatives highly depends on whether the goal is biomass generation or nutrient capture.

Agro-industrial activities generate significant amounts of organic waste and a variety of effluents, thus posing environmental challenges. Viticulture in Argentina, covering 204,847 ha in 2023, faces water scarcity as a limiting factor conditioning its production. This industry produces large volumes of grape marc, sediments, and stalks, which can be valorized into products like alcohol, tartaric acid, and compost. However, these valorization processes generate effluents with high organic load and salinity, further stressing water resources. This study explores the potential of utilizing these effluents to cultivate plant biomass in arid regions (sorghum or perennial pasture), which could serve as bioenergy, animal feed, or composting co-substrates, contributing to circular bioeconomy principles. Sorghum plots showed better establishment and higher dry biomass yield (32.6 Tn/ha) compared to pasture (6.5 Tn/ha). Sorghum demonstrated better tolerance to saline soils and high salinity effluents, aligning with previous studies. Although pasture had lower biomass yield, it was more efficient in nutrient uptake, concentrating more NPK, ash, and soluble salts. Sorghum's higher yield compensates for its lower nutrient concentration. For biomass production, sorghum is preferable, but if nutrient capture from effluents is prioritized, summer polyphytic pastures are more suitable. These results suggest that the final selection between plant biomass alternatives highly depends on whether the goal is biomass generation or nutrient capture.