Agronomy | https://www.mdpi.com/journal/agronomy | Published 12 July 2020

Supplementary LED Interlighting Improves Yield and Precocity of Greenhouse Tomatoes in the Mediterranean

Ivan Paucek ¹, Giuseppina Pennisi ^1,* , Alessandro Pistillo ¹, Elisa Appolloni ¹, Andrea Crepaldi ², Barbara Calegari ³, Francesco Spinelli ¹ , Antonio Cellini ¹ ,Xavier Gabarrell ⁴ , Francesco Orsini ¹ and Giorgio Gianquinto ¹

1 DISTAL–Department of Agricultural and Food Sciences, Alma Mater Studiorum–University of Bologna, viale Fanin 44, 40127 Bologna, Italy; ivan.paucekpagan@studio.unibo.it (I.P.); alessandro.pistillo@studio.unibo.it (A.P.); elisa.appolloni3@unibo.it (E.A.); francesco.spinelli3@unibo.it (F.S.); antonio.cellini2@unibo.it (A.C.); f.orsini@unibo.it (F.O.); giorgio.gianquinto@unibo.it (G.G.)
2 Flytech srl, Via dell’Artigianato, 65, 32016 Alpago, Belluno, Italy; andrea.crepaldi@flytech.it
3 I-POM Pellerossa, Via Cantapoiana, 12, 40054 Mezzolara di Budrio, Bologna, Italy; b.calegari@ipom.biz
4 Sostenipra Research Group (SGR 01412), Institut de Ciència i Tecnologia Ambientals (ICTA-UAB) (MDM-2015-0552), Z Building, Universitat Autònoma de Barcelona (UAB), Campus UAB, Bellaterra, 08193 Barcelona, Spain; Xavier.Gabarrell@uab.cat
* Correspondence: giuseppina.pennisi@unibo.it

In Northern Europe, the use of light–emitting diodes (LEDs) is widely adopted in protected horticulture, enabling to enhance plant growth by ensuring needed radiative fluxes throughout seasons. Contrarily, the use of artificial lighting in Mediterranean greenhouse still finds limited applications. In this study, the effects of supplemental LED interlighting on vegetative development, fruit growth, yield, and fruit quality of high-wire tomato plants (Solanum lycopersicum L. cv. ‘Siranzo’) during spring and summer season were addressed in a hydroponic greenhouse in Italy. Plants were either grown under natural solar radiation (control), or by adding supplemental LED interlighting. LED treatment featured red (R) and blue (B) light (RB ratio of 3) and a photosynthetic photon flux density of 170 µmol m^–2 s^–1 for 16 h d^–1. Supplemental LED interlighting enhanced yield as a result of increased fruit weight and dimension. While no effects on soluble solids content and fruit color at harvesting were observed, supplemental LED interlighting accelerated ripening by one week in spring and two weeks in summer and this also resulted in increased cumulated productivity (+16%) as compared to control treatment. Overall, supplemental LED interlighting can represent a feasible technology for tomato greenhouse production also in the Mediterranean region.
View Full-Text

Science Direct | https://www.sciencedirect.com/ | Published 9 June 2020

Optimal light intensity for sustainable water and energy use in indoor cultivation of lettuce and basil under red and blue LEDs

Giuseppina Pennisi ^a,b,c, Alessandro Pistillo ^a, Francesco Orsini ^a,*, Antonio Cellini ^a, Francesco Spinelli ^a, Silvana Nicola ^b, Juan A. Fernandez ^c, Andrea Crepaldi ^d, Giorgio Gianquinto ^a, Leo F.M. Marcelis ^e

a DISTAL – Department of Agricultural and Food Sciences, ALMA MATER STUDIORUM – Bologna University, Bologna, Italy
b DISAFA-VEGMAP, Department of Agricultural, Forest and Food Sciences, University of Turin, Turin, Italy
c Departamento de Ingeniería Agronómica, Universidad Politécnica de Cartagena, Cartagena, Spain
d Flytech s.r.l., Belluno, Italy
e Horticulture & Product Physiology Group, Wageningen University, Wageningen, the Netherlands

Indoor plant cultivation systems are gaining increasing popularity because of their ability to meet the needs of producing food in unfavourable climatic contexts and in urban environments, allowing high yield, high quality, and great efficiency in the use of resources such as water and nutrients. While light is one of the most important environmental factors affecting plant development and morphology, electricity costs can limit the widespread adoption of indoor plant cultivation systems at a commercial scale. LED lighting technologies for plant cultivation are also rapidly evolving, and lamps for indoor cultivation are often designed to optimize their light emissions in the photosynthetically active spectrum (i.e. red and blue), in order to reduce energetic requirements for satisfactory yield. Under these light regimens, however, little information is available in literature about minimum photosynthetic photon flux density (PPFD) for indoor production of leafy vegetables and herbs, while existing literature often adopts light intensities from 100 to 300 µmol m^–2 s^–1. This study aims at defining the optimal PPFD for indoor cultivation of basil (Ocimum basilicum L.) and lettuce (Lactuca sativa L.), by linking resource use efficiency to physiological responses and biomass production under different light intensities. Basil and lettuce plants were cultivated at 24 °C and 450 µmol mol^–1 CO₂ under red and blue light (with red:blue ratio of 3) and a photoperiod of 16 h d-1 of light in growth chambers using five PPFD (100, 150, 200, 250 and 300 µmol m^–2 s^–1, resulting in daily light integrals, DLI, of 5.8, 8.6, 11.5, 14.4 and 17.3 µmol m^–2 s^–1, respectively). A progressive increase of biomass production for both lettuce and basil up to a PPFD of 250 µmol m^–2 s^–1 was observed, whereas no further yield increases were associated with higher PPFD (300 µmol m^–2 s^–1). Despite the highest stomatal conductance associated to a PPFD of 250 µmol m^–2 s^–1 in lettuce and to a PPFD≥200 µmol m^–2 s^–1 in basil, water use efficiency was maximized under a PPFD≥200 µmol m^–2 s^–1 in lettuce and PPFD≥250 µmol m^–2 s^–1 in basil. Energy and light use efficiencies were increased under a PPFD of 200 and 250 µmol m^–2 s^–1 in lettuce and under a PPFD of 250 µmol m^–2 s^–1 in basil. Furthermore, in lettuce grown under 250 µmol m^–2 s^–1 antioxidant capacity, phenolics and flavonoids were higher as compared with plants supplied with PPFD≤150 µmol m^–2 s^–1. Accordingly, a PPFD of 250 µmol m^–2 s^–1 seems suitable for optimizing yield and resource use efficiency in red and blue LED lighting for indoor cultivation of lettuce and basil under the prevailing conditions of the used indoor farming set-up.
View Full-Text

Colture Protette | https://coltureprotette.edagricole.it/ | Published April 2020

Led interlighting su pomodoro in serra

Negli ultimi anni, l’applicazione di Led per l’illuminazione supplementare in serra si è ampiamente diffusa in Nord America, Europa settentrionale e Giappone, in sostituzione a tecnologie di illuminazione più diffuse come le lampade al sodio ad alta pressione (Gunnlaugsson & Adalsteinsson, 2005). I principali benefici offerti dalla tecnologia Led si evidenziano nella possibilità di modulare lo spettro tramite l’impiego di diodi con specifiche lunghezze d’onda, nell’elevata vita utile delle lampade e nell’efficienza di conversione dell’energia elettrica in radiazione luminosa, riducendo così i costi energetici. Le potenzialità offerte dalla tecnologia Led sono numerose: studi recenti hanno dimostrato che la possibilità di adattare lo spettro alle diverse specie vegetali, così come alle diverse fasi fenologiche della coltura, può consentire non solo di aumentare la resa produttiva, ma anche di migliorare le proprietà nutrizionali del prodotto, come nel caso del contenuto di sostanze antiossidanti e del profilo aromatico in basilico (Pennisi et al., 2019). Inoltre, grazie alla limitata dispersione termica di queste lampade rispetto alle precedenti tipologie, è possibile posizionarle in prossimità della chioma o addirittura all’interno di essa, come nelle cosiddette lampade interlighting comunemente usate per la coltivazione di pomodoro (Gunnlaugsson & Adalsteinsson, 2005). Si considera, inoltre, che la possibilità di concentrare la luce nelle regioni in cui si trovano i picchi di assorbimento della clorofilla (blu tra 400-500 nm e rosso tra 600-700 nm) possa contribuire a migliorare ulteriormente l’efficienza d’uso dell’energia, apportando significativi aumenti di resa, soprattutto in condizioni di limitato accesso alla radiazione solare diretta. Mentre l’efficacia dei Led nell’aumentare la resa produttiva nelle serre del nord Europa è stata validata da numerosi studi, ad esempio su pomodoro (Kaiser et al., 2019; Tewolde et al., 2018) e colture floricole (Bergstrand and Schussler, 2013), nell’orticoltura mediterranea l’adozione di questa tipologia di illuminazione è, ad oggi, estremamente limitata. Ciò è probabilmente associabile sia al moderato livello tecnologico del comparto serricolo nel sud Europa che a una generalmente scarsa percezione della luce come fattore limitante a queste latitudini. Invero, a fronte della stagionalità produttiva del comparto (più remunerativa nelle stagioni invernali) e delle elevate densità colturali all’interno degli apprestamenti produttivi (al fine di massimizzare l’efficienza energetica associata alla climatizzazione della serra), si osserva spesso un forte e repentino decadimento dei tassi fotosintetici spostandosi dalla parte apicale della chioma alle foglie di altezze inferiori, ad esempio su cetriolo.
View Full Text

Colture Protette | https://coltureprotette.edagricole.it/ | Published January 2020

Luce artificiale per sistemi indoor

I cambiamenti climatici e il deperimento delle risorse naturali disponibili rappresentano importanti sfide per i sistemi agricoli attuali. Nei prossimi decenni sarà necessario soddisfare richieste crescenti di alimenti per sfamare città sempre più grandi, cercando di ridurre il più possibile l’impatto ambientale. In questo contesto si sta diffondendo l’uso di sistemi innovativi di coltivazione, noti come indoor farms o Plant factories with artificial lighting (Pfal) o vertical farms, indipendenti dalla luce naturale e dal suolo agrario, che possono essere sviluppati in ambiente urbano, consentendo la riconversione di edifici abbandonati in spazi di produzione agricola. In tali sistemi la coltivazione avviene in ambienti chiusi in cui è possibile controllare tutti i fattori ambientali. Ciò permette di produrre durante tutto l’anno e di aumentare le rese fino a 23 volte rispetto ai sistemi tradizionali. Inoltre, permette di migliorare la qualità e ottenere una maggiore stabilità nella produzione. L’impiego dell’idroponica migliora l’efficienza d’uso delle risorse rispetto ai tradizionali sistemi di coltivazione, consentendo un risparmio di acqua (fino al 97%) e di nutrienti, grazie al ricircolo della soluzione nutritiva drenata. L’illuminazione artificiale è imprescindibile per sviluppare questi sistemi. Ne consegue che, ad oggi, lo sviluppo e la diffusione del comparto siano limitati dai sostenuti costi energetici e di impianto.
View Full Text

Nature | https://www.nature.com/srep/ | Published 01 October 2019

Resource use efficiency of indoor lettuce (Lactuca sativa L.) cultivation as affected by red:blue ratio provided by LED lighting

Giuseppina Pennisi ^1,2,3, Francesco Orsini ¹, Sonia Blasioli ¹, Antonio Cellini ¹, Andrea Crepaldi ⁵, Ilaria Braschi ¹, Francesco Spinelli ¹, Silvana Nicola ², Juan A. Fernandez ³,Cecilia Stanghellini ⁶, Giorgio Gianquinto ¹ & Leo F . M. Marcelis ⁴

1 DISTAL – Department of Agricultural and Food Sciences, ALMA MATER STUDIORUM – Bologna University,Bologna, Italy.
2 DISAFA–VEGMAP, Department of Agricultural, Forest and Food Sciences, University of Turin,Turin, Italy.
3 Departamento de Ingeniería Agronómica, E.T.S. Ingeniería Agronómica, Universidad Politécnica deCartagena, Cartagena, Spain.
4 Horticulture & Product Physiology Group, Wageningen University, Wageningen, The Netherlands.
5 Flytech s.r.l., Belluno, Italy.
6 Wageningen UR Greenhouse Horticulture, Wageningen, The Netherlands.

LED lighting in indoor farming systems allows to modulate the spectrum to fit plant needs. Red (R) and blue (B) lights are often used, being highly active for photosynthesis. The effect of R and B spectral components on lettuce plant physiology and biochemistry and resource use efficiency were studied. Five red:blue (RB) ratios (0.5-1-2-3-4) supplied by LED and a fluorescent control (RB = 1) were tested in six experiments in controlled conditions (PPFD = 215 µmol m^–2 s^–1, daylength 16 h). LED lighting increased yield (1.6 folds) and energy use efficiency (2.8 folds) as compared with fluorescent lamps. Adoption of RB = 3 maximised yield (by 2 folds as compared with RB = 0.5), also increasing leaf chlorophyll and flavonoids concentrations and the uptake of nitrogen, phosphorus, potassium and magnesium. As the red portion of the spectrum increased, photosystem II quantum efficiency decreased but transpiration decreased more rapidly, resulting in increased water use efficiency up to RB = 3 (75g FW L^–1 H₂O). The transpiration decrease was accompanied by lower stomatal conductance, which was associated to lower stomatal density, despite an increased stomatal size. Both energy and land surface use efficiency were highest at RB ≥ 3. We hereby suggest a RB ratio of 3 for sustainable indoor lettuce cultivation.
View Full-Text

Sustainability | https://www.mdpi.com/journal/sustainability | Published 27 July 2019

Modelling Environmental Burdens of Indoor-Grown Vegetables and Herbs as Affected by Red and Blue LED Lighting

Giuseppina Pennisi ^1,2,3,†, Esther Sanyé-Mengual ¹,†, Francesco Orsini ^1,*,†, Andrea Crepaldi ⁴, Silvana Nicola ², Jesús Ochoa ³, Juan A. Fernandez ³ and Giorgio Gianquinto ¹

1 Department of Agricultural and Food Sciences (Distal), Research Centre in Urban Environment for Agriculture and Biodiversity (ResCUE-AB), University of Bologna, Viale Fanin, 44, 40127 Bologna, Italy
2 Department of Agricultural, Forest and Food Sciences, DISAFA-VEGMAP, University of Turin, Largo Paolo Braccini, 2, 10097 Grugliasco, Italy
3 Department of Agricultural Engineering, Universidad Politécnica de Cartagena, Paseo Alfonso XIII 48, 30203 Cartagena, Spain
4 Flytech s.r.l., Via dell'Artigianato, 65, Zona artigianale Paludi, 32010 Belluno, Italy
* Author to whom correspondence should be addressed.
† These authors equally contributed to this publication.

Notwithstanding that indoor farming is claimed to reduce the environmental pressures of food systems, electricity needs are elevated and mainly associated with lighting. To date, however, no studies have quantified the environmental and economic profile of Light Emitting Diodes (LED) lighting in indoor farming systems. The goal of this study is to quantify the effect of varying the red (R) and blue (B) LED spectral components (RB ratios of 0.5, 1, 2, 3 and 4) on the eco-efficiency of indoor production of lettuce, chicory, rocket and sweet basil from a life cycle perspective. The functional unit of the assessment was 1 kg of harvested fresh plant edible product, and the International Reference Life Cycle Data System (ILCD) method was employed for impact assessment. Even though most of the materials of the LED lamp and electronic elements were imported from long distances (14,400 km), electricity consumption was the largest contributor to the environmental impacts (with the LED lamps being the main electricity consumers, approximately 70%), apart from the resources use indicator, where the materials of the lamps and the mineral nutrients were also relevant. RB0.5 was the most energy-efficient light treatment but had the lowest eco-efficiency scores due to the lower crop yields.
View Full-Text

Frontiers in Plant Science | www.frontiersin.org | Original Research Published 13 March 2019

Unraveling the Role of Red:Blue LED Lights on Resource Use Efficiency and Nutritional Properties of Indoor Grown Sweet Basil

Giuseppina Pennisi ^1,2,3, Sonia Blasioli ¹, Antonio Cellini ¹, Lorenzo Maia ¹, Andrea Crepaldi ⁴, Ilaria Braschi ¹, Francesco Spinelli ¹, Silvana Nicola ², Juan A. Fernandez ³, Cecilia Stanghellini ⁵, Leo F. M. Marcelis ⁶, Francesco Orsini ^1,6 and Giorgio Gianquinto ¹

1 DISTAL – Department of Agricultural and Food Sciences and Technologies, Alma Mater Studiorum – Universitá di Bologna, Bologna, Italy
2 DISAFA–VEGMAP, Department of Agricultural, Forest and Food Sciences, University of Turin, Turin, Italy
3 Departamento de Producción Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Universidad Politécnica de Cartagena, Cartagena, Spain
4 Flytech s.r.l., Belluno, Italy
5 Wageningen UR Greenhouse Horticulture, Wageningen, Netherlands
6 Horticulture and Product Physiology Group, Wageningen University & Research, Wageningen, Netherlands

Indoor plant cultivation can result in significantly improved resource use efficiency (surface, water, and nutrients) as compared to traditional growing systems, but illumination costs are still high. LEDs (light emitting diodes) are gaining attention for indoor cultivation because of their ability to provide light of different spectra. In the light spectrum, red and blue regions are often considered the major plants energy sources for photosynthetic CO₂ assimilation. This study aims at identifying the role played by red:blue (R:B) ratio on the resource use efficiency of indoor basil cultivation, linking the physiological response to light to changes in yield and nutritional properties. Basil plants were cultivated in growth chambers under five LED light regimens characterized by different R:B ratios ranging from 0.5 to 4 (respectively, RB_0.5, RB₁, RB₂, RB₃, and RB₄), using fluorescent lamps as control (CK₁). A photosynthetic photon flux density of 215 µmol m^–2 s^–1 was provided for 16 h per day. The greatest biomass production was associated with LED lighting as compared with fluorescent lamp. Despite a reduction in both stomatal conductance and PSII quantum efficiency, adoption of RB₃ resulted in higher yield and chlorophyll content, leading to improved use efficiency for water and energy. Antioxidant activity followed a spectral-response function, with optimum associated with RB₃. A low RB ratio (0.5) reduced the relative content of several volatiles, as compared to CK₁ and RB ≥ 2. Moreover, mineral leaf concentration (g g^–1 DW) and total content in plant (g plant^–1) were influences by light quality, resulting in greater N, P, K, Ca, Mg, and Fe accumulation in plants cultivated with RB³. Contrarily, nutrient use efficiency was increased in RB ≤ 1. From this study it can be concluded that a RB ratio of 3 provides optimal growing conditions for indoor cultivation of basil, fostering improved performances in terms of growth, physiological and metabolic functions, and resources use efficiency.
View Full-Text

UrbanFarm 2019: FlyGrow sponsors the international urban regeneration competition

FlyGrow, through Flytech, is sponsoring UrbanFarm 2019, the international competition organised by the Universities of Bologna and Florence to design innovative urban farming systems. The aim of the challenge is to encourage students from all over the world to come up with solutions to convert unused spaces in towns and cities into areas of agricultural production.

Three cities in Italy, Bologna, Belluno and Conegliano, have provided the spaces to redevelop and the challenge is to combine sustainability with strong entrepreneurial potential: in fact, the projects will also be judged on their contribution to the local community, namely the job opportunities they create.

The competition was inspired by the student challenge 'Design the Ultimate Urban Greenhouse' organised by Wageningen University and Research in the Netherlands and is open to teams of students from around the world who belong to the faculties of Agriculture, Biology, Architecture, Design, Economics, Engineering and Social Studies. The teams may be multidisciplinary and a group has been set up on Facebook to help students find a team looking for their particular expertise.

The students are being asked to come up with innovative solutions that have an impact across the board: not only will the buildings and places which are currently abandoned become new centres for agricultural and food production, they will also promote study and the farming culture. The architectural and technological redevelopment of the locations selected, each with its own unique features, will enable them to become an active part of the urban and social fabric of their city once again.

Teams from universities all over the world can take part, they do not necessarily have to be made up of students from the same university and can choose the location, or locations, they wish to work on. The universities organising the competition (Bologna and Florence) have selected an interdisciplinary jury made up of international experts who will award the three winning projects prizes of Euro 6000, Euro 1000 and Euro 500 respectively, one for each location. The deadline for submitting projects for the preliminary selection is 1 December 2018, while the final selection and award ceremony will take place during the Novel Farm trade show in Pordenone on 13 and 14 February 2019.

For more information, visit the official UrbanFarm 2019 website

The University of Bologna in partnership with FlyGrow: the preliminary results are published.

Over the past few years, the urban farming trend has become more and more popular around the globe: with the demand for food in urban areas growing constantly, agriculture is called upon to cultivate new spaces. To meet the needs of indoor and soilless farming, studies must focus on solutions which are geared to the limitations of this kind of farming, while still guaranteeing high-quality products.

FlyGrow has entered into a partnership with the University of Bologna to determine the feasibility of LED lighting in urban and indoor farming for three key reasons:
- LED technology is more sustainable as regards consumption and the life span of the light source.
- The surface temperature of LED lighting is lower than that of other solutions.
- The colour combinations of the light can be varied using LED technology.

The last point has been the focus of the preliminary research, and in particular the comparison between the effects of lighting with a greater ratio of blue or red on vegetable crops and low plants.

The initial results of this research were made public in September 2017 at the 1st International Symposium on Greener Cities for More Efficient Ecosystem Services in a Climate Changing World, organised in Bologna by the International Society for Horticultural Sciences (ISHS). The data were presented during the talk Different red:blue ratios in LED lighting affect productivity, nutritional and physiological parameters of indoor hydroponically grown lettuce.

The comparison between lights of different composition was also the subject of a talk in August 2018 at the 3rd International Symposium on Innovation and New Technologies in Protected Cultivation, organised by the International Society for Horticultural Sciences (ISHS). The studies conducted in partnership with FlyGrow formed the basis of the talk Improved red and blue ratio in LED lighting for indoor cultivation of leafy vegetables.

The assessment of the ecological impact of these solutions, on the other hand, was the subject of the poster presented in June 2018 in Bologna at the XII Giornate Scientifiche SOI (Italian Society of Vegetables, Flowers and Fruit) entitled Eco-efficiency assessment of LED lighting solutions for urban farming.

The complete study is due to be published soon and will contain all the criteria, experiments and results.
Contact us for more information