Agronomic and Environmental Assessment of a Polyculture Rooftop Soilless Urban Home Garden in a Mediterranean City

Boneta, Anna; Rufí-Salís, Martí; Ercilla-Montserrat, Mireia; Gabarrell, Xavier; Rieradevall, Joan

doi:10.3389/fpls.2019.00341

Cited by 40 publications

(32 citation statements)

References 22 publications

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“…For example, Sanyé-Mengual et al (2015b) assessed the performance of a rooftop home garden in Bologna (Italy), concluding that year-round polyculture, i.e., growing a wide variety of vegetables, meets the residents' demand for diversified foods. Similarly, Boneta et al (2019) found that 8.2 m 2 of rooftop polyculture can cover up to 62% of the average vegetable consumption per capita in the region of Catalonia. In addition to Boneta et al (2019), Orsini et al (2014) described the existence of large variations in the yields throughout the year when producing food in urban rooftops, as well as the difficulties found in producing vegetables in cold periods.…”

Section: Introductionmentioning

confidence: 90%

“…Similarly, Boneta et al (2019) found that 8.2 m 2 of rooftop polyculture can cover up to 62% of the average vegetable consumption per capita in the region of Catalonia. In addition to Boneta et al (2019), Orsini et al (2014) described the existence of large variations in the yields throughout the year when producing food in urban rooftops, as well as the difficulties found in producing vegetables in cold periods.…”

Section: Introductionmentioning

confidence: 90%

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Identifying eco-efficient year-round crop combinations for rooftop greenhouse agriculture

Rufí-Salís

Petit‐Boix

Villalba

et al. 2020

Int J Life Cycle Assess

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Purpose: Rooftop greenhouses (RTGs) are agricultural systems that can reduce the food supply chain by producing vegetables in unused urban spaces. However, to date, environmental assessments of RTGs have only focused on specific crops, without considering more long-term impacts resulting from seasonality, combinations of crops, and non-operational time. We analyze the production of an RTG over 5 years to determine the crop combinations that minimize yearly environmental impacts while diversifying the food supply. Methods: The system study consists of an integrated RTG (i-RTG) with hydroponic irrigation in Barcelona (Mediterranean climate). By using life cycle assessment (LCA) with the ReCiPe hierarchical midpoint method, we evaluated the environmental performance of 25 different crop cycles and seven species cultivated during the 2015-2018 period. Two functional units are used: 1 kg of edible fresh production and 1 unit of economic value (€) in the wholesale market. The system boundaries consider two subsystems: infrastructure (greenhouse structure, rainwater harvesting system and auxiliary equipment) and operational (fertilizers and their emissions into water and substrate). In addition, we perform an eco-efficiency analysis, considering the carbon footprint of the crop cycles and their value at the wholesale market during their harvesting periods. Results and discussion: Spring tomato cycles exerted the lowest impacts in all categories, considering both functional units, due to the high yields obtained. In contrast, spinach and arugula had the highest impacts. Regarding relative impact, the greenhouse structure presented a large impact, while fertilizer production had notable relative contributions in tomato cycles. Moreover, nitrogen and phosphorus emissions from fertigation exerted the majority of the impact on freshwater and marine eutrophication. Growing two consecutive tomato cycles was demonstrated to be the best alternative with the functional unit of yield (0.49 kg CO 2 eq./kg), whereas a long spring tomato cycle combined with bean and lettuce cycles in the autumn was the best scenario with the functional unit of economic value (0.70 kg CO 2 eq./€). Conclusions:The present study has demonstrated that increasing the diversity of the system leads to better environmental performance of greenhouse urban agriculture if suitable crops are selected for the winter season. The functional unit involving the economic value and the eco-efficiency analysis were useful to demonstrate the capability of the framing system to produce added-value vegetables under harsher conditions, while categorizing and classifying the crops to select the most suitable based on economic and environmental parameters.

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Section: Introductionmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 90%

Identifying eco-efficient year-round crop combinations for rooftop greenhouse agriculture

Rufí-Salís

Petit‐Boix

Villalba

et al. 2020

Int J Life Cycle Assess

Self Cite

View full text Add to dashboard Cite

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“…Catalogna Verde). Hydroponic production in perlite grow bags was selected as the control system as it is a standard system for horticultural production in the Mediterranean region, and this system can be used in both commercial and small-scale urban growing contexts [30,39,81].…”

Section: Novel Sustainable Growing Media Alternativesmentioning

confidence: 99%

“…Agronomy 2020, 10, x FOR PEER REVIEW 4 of 28 scale urban growing contexts [30,39,81]. These media were also tested on their ability to mitigate stress in lettuce crops during an induced drought period, in order to understand their potential to reduce irrigation requirements and buffer shocks in the hydroponic system.…”

Section: Growing Media Preparationmentioning

confidence: 99%

Evaluation of Recycled Materials as Hydroponic Growing Media

et al. 2020

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Conventional soilless growing media, such as perlite, are mined from nonrenewable resources and can only be disposed of in landfills after limited use. There is a need to investigate novel, sustainable growing media adapted from waste or engineered to be reused over multiple cycles. This study investigated waste almond shells and a recycled plastic drainage plank as hydroponic growing media alternatives. Physiochemical properties were evaluated, and a germination and greenhouse growth trial was conducted to understand the effect these media have on production and nutritional quality of lettuce (Lactuca sativa L. cv. Catalogna Verde). Drought testing was carried out to understand how the media affected the lettuce’s response to water stress. In comparison to perlite, yields under regular irrigation were reduced by 52% in almond shells and 72% in plastic planks, although lettuce grown in almond shells still obtained commercially relevant yields. Reduced yields in almond shells were likely caused by the shell’s high salinity. Lettuce growth in plastic planks was limited by impeded root growth and low water-holding capacity. In conclusion, with minor alterations, almond shells could be used as a sustainable growing media alternative to perlite in hydroponic lettuce production. More research is needed to manufacture the planks to be conducive to plant growth.

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“…However, UA is not free of environmental impacts. Similar to conventional agricultural systems, nutrient discharge resulting from intensive fertilizer use is particularly problematic due its impact on water eutrophication ( Muñoz et al, 2008 ; Torrellas et al, 2012 ; Romero-Gámez et al, 2014 , 2012 ; Boneta et al, 2019 ). The application of circular economy strategies in UA systems could help mitigate these impacts.…”

Section: Introductionmentioning

confidence: 99%

Closed-Loop Crop Cascade to Optimize Nutrient Flows and Grow Low-Impact Vegetables in Cities

et al. 2020

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Urban agriculture systems can significantly contribute towards mitigating the impacts of inefficient and complex food supply chains and increase urban food sovereignty. Moreover, improving these urban agriculture systems in terms of nutrient management can lead to a better environmental performance. Based on a rooftop greenhouse in the Barcelona region, we propose a cascade system where the leachates of a tomato cycle from January to July (donor crop) are used as the main irrigation source for five successive lettuce cycles (receiving crop). By determining the agronomic performance and the nutrient metabolism of the system, we aimed to define the potential of these systems to avoid nutrient depletion and mitigate eutrophication, while scaling the system in terms of nutrient supply between the donor and the receiving crops. The results showed that low yields (below 130 g per lettuce plant) are obtained if a cascade system is used during the early stage of the donor crop, as the amount of nutrients in donor’s leachates, specially N (62.4 mg irrigated per plant in the first cycle), was not enough to feed the lettuce receiving crop. This effect was also observed in the nutrient content of the lettuce, which increased with every test until equaling the control (4.4% of N content) as the leachates got richer, although too high electrical conductivity values (near 3 dS/m) were reached at the end of the donor crop cycle. Findings on the uptake of the residual nutrient flows showed how the cascade system was able to take advantage of the nutrients to produce local lettuce while mitigating the effect of N and P in the freshwater and marine environments. Considering our case study, we finally quantified the scale between the donor and receiving crops and proposed three major ideas to optimize the nutrient flows while maintaining the yield and quality of the vegetables produced in the receiving crop.

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Agronomic and Environmental Assessment of a Polyculture Rooftop Soilless Urban Home Garden in a Mediterranean City

Cited by 40 publications

References 22 publications

Identifying eco-efficient year-round crop combinations for rooftop greenhouse agriculture

Identifying eco-efficient year-round crop combinations for rooftop greenhouse agriculture

Evaluation of Recycled Materials as Hydroponic Growing Media

Closed-Loop Crop Cascade to Optimize Nutrient Flows and Grow Low-Impact Vegetables in Cities

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