The benefits of informed management of sunlight in production greenhouses and polytunnels

The effective management of light is beneficial for growers plants in greenhouses, polytunnels and under cloches. materials structures used to construct these environments often create light-limited conditions crops change the spectral composition sunlight they receive. Combining practical measures, drawn from knowledge plant photobiology, allows monitor, forecast optimise their growing environment according its geographical location crop grown. Improved through measures could be expected improve food quality yield, potentially reduce use energy, water pesticides. Horticultural production greenhouses expands viable geographic range many species extends productive season. These semi-controlled buffer natural fluctuations heat, cold hold potential security with a low environmental footprint. Over last decade, technological advances cladding materials, smart filters, photo-electric cells energy LED lighting have created opportunities within structures. In parallel, there been large underpinned by progress identifying mechanisms photomorphogenesis photoprotection, mediated photoreceptors interactions, across regions spectrum. However, remains unexploited synthesise transfer fields horticulture, particularly respect tailoring specific locations systems. Here, we systematically explain (1) value modelling monitoring patterns allow informed design growth environment; (2) means optimising selection structures; (3) requirements different terms amount that will benefit yield quality; (4) combine this sunlight; and, finally, (5) additional benefits actions may bring society at large, beyond themselves, efficiency. Tehokas valoympäristön hallinta on hyödyllistä kasvihuoneissa, muovitunneleissa ja muissa suojatuissa tiloissa kasvatettaville kasveille. Näiden tilojen rakentamiseen käytetyt materiaalit rakenteet vähentävät usein kasvien saaman valon määrää muuttavat niiden vastaanottaman auringonvalon spektrin koostumusta. Kasvien valobiologiseen tietämykseen perustuvien käytännön toimenpiteiden käyttäminen antaa viljelijöille mahdollisuuden seurata, ennustaa optimoida kasvuympäristön olosuhteita sen maantieteellisen sijainnin viljellyn kasvilajin mukaan. Paremmalla hallinnalla voidaan parantaa sadon laatua sekä mahdollisesti vähentää energian, veden torjunta-aineiden käyttöä. Une gestion efficace de la lumière est bénéfique pour les cultivateurs travaillant en serres, tunnels plastiques et Les matériaux utilisés construire ces environnements créés souvent des limitantes plantes modifient venant du soleil qu'elles reçoivent. En combinant mesures pratiques qui sont inspirées nos connaissances photobiologie, seront à même surveiller, prédire optimiser leur environnement plantation accord avec localisation géographique plante utilisée. Avec une meilleure travers mesures, s'attend améliorer qualité nourriture, le rendement, potentiellement l'utilisation d'énergie, d'eau, ????????????????????????????????????????????????????????????????????????, ?????????????????????????????????????, ??????????????????????, ????????????????????????????????, ????????????, ?????????????????? A great challenge 21st century how efficiency can continue improved, efficient resource use, while maintaining yields along better high nutritional (FAO, 2014; IPCC, 2019; Ort al., 2015). suite approaches needed meet challenge, including improvements varieties available farmers growers, integrated pest nutrition soil science. addition biological aspects, scope manipulate approach optimum (Bergstrand, 2017; Poel & Runkle, 2017). Greenhouses, (typically walk-in wide crops, over areas; sometimes called ‘high tunnels’) cloches (plastic coverings less than metre are employed commercially, e.g., strawberries or salads, small-scale production; ‘low provide seasonal year-round protection undesired temperature, moisture, wind, irradiance extreme weather events. application new technologies supplemental lighting, produce spectrum radiation which matches photosynthesis provokes desirable changes form, already reaping more energy-efficient (Nelson Bugbee, 2014). Further, polytunnels, tuning reaching plants, maximised (Zheng 2019). purpose manipulating depends whether receive predominately insufficient excessive radiation. protected cropping systems, ambient solar filtered (by refer greenhouse window-panes, panels climate screens, plus plastic heat transmitted). Well-informed variety structural available, selectively filter spectrum, should make best crop's (Folta Carvalho, 2015; Kotilainen 2018). Even modest alterations configuration affect shading (i.e., received plants). consequences rate, morphology, physiology, phenology (the timing development) biochemistry; thus, nutrition, desirability (Alvarado 2020; Folta gives greater particular given (Impron 2007). Typically, mapping has not prioritised because relatively little attention focussed productivity compared other factors. This lack awareness overcome dissemination information researchers manufacturers groups representing growers. To date, most consultants concentrate thermal characteristics regulating temperature when designing plastics environments, giving attenuation those utilised perception light, is, photosynthetically active (PAR) 400–700 nm (similar region visible people) ultraviolet (UV-B 290–315 UV-A 315–400 nm). Beyond affects deficiency largely occurs instruments required measure accurately until recently expensive. Furthermore, reliable estimates economic gleaned improving as highly specific. All issues mean biosciences slow. Growers remain convinced about cost–benefit trade-off purchasing devices require training interpret measurements irradiance, investment tailor purposes. focussing sunlight, suggest several steps towards addressing shortfall among researchers, manufacturers: characterisation (greenhouses polytunnels); illustration substituting one material another produce; existing plants' photobiology guide decisions composition; combining preceding involving substitution responses quality, simple models might able adjust suit needs; consider end-users use. shade-houses typically either protect detrimental effects combined temperatures; moisture rainfall; events such intense hail dust storms; increase control fluctuating combination factors depending season location. At basic level, simulation map environment, enabling pre-emptively identify hot-spots excessively shaded areas. Where allow, modern commercial designed homogeneous illuminated areas shading, otherwise cause reductions (Figure S1). optimal height shape well orientation, differs latitude accounting up 17% 2007; Sahdev Xu 2020). Thus, planning stage ensure selected structure appropriate crop, later grower correctly select position 1). north–south versus east–west orientation determine daily pattern (Sethi, 2009; Ting Giacomelli, 1987). North–south ridges maximise annual ingress whereas enter winter (14% 50°N), critical latitudes. Additionally, highlight effect dirt algae hence need frequent cleaning windows, surrounding buildings, topography aging total (Casilla, 2013; von Zabeltitz, 2011). effects, influence vegetation usually considered but reflected far 50 m away red far-red ratio incident (660 nm/730 nm), during periods elevation (Kotilainen facility (e.g., benches, vents irrigation), display angle thickness glass cladding, also optimised location—which determines sun day length—balance requiring targeted enhancement Sensors PAR instantaneous readings units photons (Watts ?mol m?2), integral (DLI) day. Unfortunately, interpretable still gathered using sensors foot-candles lux do directly scale responses. Measuring useful variation involved photomorphogenesis, photoprotection shade avoidance facilitate assessment required, itself, grown, space. Local remote meteorological services feed into whole calculated, enables feedback repeated illumination. Denmark, an achieved savings 5% reducing reliance so lowering costs electricity (Kjaer 2011, 2012). While systems becoming initial financial outlay expertise individual install provides barrier uptake. provision general guidelines combinations would help users decisions. value, increased market facilitated facilities. Two contrasting limited excess high-latitude locations, where much year irradiances, it advantageous transparency transmitted UV blue (400–500 nm) reach (Quintero-Arias 2021; Snowden 2016; 1987; Wargent, 2017) optical properties important, durability, double single layers/panels used. considerations represent compromise between retention (Ting filters spray-on coatings diffuse fraction (Riga Benedicto, absorb reflect infra-red (El-Bashir Timmermans type ‘spectral filters’ releasing absorbing 30°C 40°C warming (Timmermans An alternative incorporate photovoltaic roof green (500–600 generate (Cossu Loik limiting unevenly obscured structure, principle, via shift enrich wavelengths give greatest photochemical 1) (Loik explored films containing dyes quantum dots short wavelength reemit some (600–700 (Parrish Ravishankar 2021). practice, effectiveness established assumes minor photobiology. necessarily case demanding aubergine (Solanum melongena) lettuce (Lactuca sativa), loss (23% lower 20% DW anthocyanin content, respectively) reported energy-saving load warm substantially inside (Chavan emerging flexibility light-limiting light/heat conditions, depend addition, requires appreciation roles affecting pests/pathogens management. intentional manipulation composition, greatly beneath them (Ili? Fallik, important considering syndrome (SAS) interacting (Ballaré Pierik, high-light scenarios, look without triggering nets screens (Alokam 2002). Maintaining ratio, avoiding depletion radiation, overcomes chemical regulators keep compact inhibiting (Latimer Whipker, 2012; Palonen 2011; Paul 2005). latitude, length time all input polytunnels. They included purpose. Likewise, grown vertical gradients fruit like tomatoes lycopersicum), foliage canopy causes reduction close ground, health ripening fruits (Shin Mapping plan countermeasures implemented diminish Such include making judicious positioning inter-row Diffusive glass, scatter materials. Under clear cloudless sky, proportion low, enable even horizontal distribution (at least 10% canopy; Shin 2021), retaining similar overall absorption leaves (Li uniform canopies leaf area index, implies self-shading Yang, 2015), helps curtail photoinhibition temperatures associated strong direct (Burgess results enhancing whole-canopy altering absorbed Shao productivity, evident fresh weight harvested (up tomato cucumber) enhanced due (Hemming Li Improvements made ground surface mulches medium. As balance, reflective mulch accelerate increasing content peach tomato, absorbs yield: example, 16% (Decoteau 1989; Lee Traditional polytunnel shorter wavelengths. research found UV-B plastic, controlled 2): form colour herbs salad (Stutte Edney, 2009). High-value short-rotation good return favourable replacing traditional alternatives transmit short-wavelength light. serve cues stimulate secondary metabolites, defence against herbivores pathogens, colouration (Robson Flavonoids, anthocyanins tannins favoured, berry production, flavour colour, perceived healthy (Tomás-Barberán Espín, 2001). It tea bushes cloth (to load) flavonoids soft fruits, northern Europe (Xu 2014), likewise southern 2013) 2). Manipulating photoreceptor-mediated tailored fit growers' requirements, reduced branching stomatal closure biomass/flower hormones (Kotiranta Williams 2022). Transmittance responsible (c +12% weight, c +41%) shelf life (firmness, slower desiccation decay) (Ibrahim lead larger (+17%–21%), interception (Zhang Analysis architecture spectra most-open canopy, allowing penetration deeper layers, was enriched 10%–17% gross level light; Dieleman Recent studies cucumbers (Cucumis sativus) maintain morphology (Jeong Qian Both upregulation 40% respectively after 5 days; 2019), although strongly conditioned (Palma Perhaps visually apparent lettuce, elevations Andes displays (2.9 times more) transparent significant latitudes, necessary precondition young tree seedlings transplant shock planting outdoors. 380 LEDs hardening Scots pine (Pinus sylvestris) Norway spruce (Picea abies) seedlings, consumed mortality irradiation always cost (Hernandez Velasco Mattsson, aid circumstances (outside latitudes winter) prior propagated higher density fitness. Manipulation way enhances outdoors Klem More understand fine-tune photomorphogenic shifting both. addressed ‘light recipes’ moderated signals location, sort Pollinating insects set being prominent (Toni Bumblebees UV, navigate (Chittka Wells, 2004), polycarbonate hinders navigation. impaired flower visibility pollinators decreases effectiveness, irradiances exacerbate issue. bumblebee colony sizes smaller clusters misshapen raspberries, bees decline pollination (reviewed Dag, 2008, Kendall Greenhouse computers wirelessly link release colonies intensity incoming extending span unproductive flying (van Velden, 2013). Further refinements system response dynamic relevant pollination. improved produced standard represents promoting activity (orientation take-off stimulus) pests pathogens. Standard cut 360 nm, horticultural purposes out 400 alternately down 290 (Fennell Spectrally selective UV-attenuating successfully restrict populations Drosophila (D. suzukii), below 405 navigate, 50% UV-transmitting (Fountain meshes attenuate potato blight outdoors, presumably sporulation Alternaria solani Phytophthora infestans (Merfield 2019) Although block thought outweigh transmittance pathogen control, reality, crop–species insufficiently studied draw conclusions balance employing transmitting part pollinator (Egan evidence suggests producing desirable, tasty robust longer shelf-life, negative fungal aforementioned herbivore vision triggered Drawbacks entering must accounted for, accelerated photodegradation equipment material, workers take precautions sunburn eyes. Eventually, altered stages development pest/pathogen agriculture, site-specific forecasts (Mitchell Sheehy, 2018; Trnka 2007), model protein wheat (Triticum aestivum) real-time nutrient status (Shu applied if bottom atmosphere, extended filtering calculated Radiative generally explore interacts constituents atmosphere (Lindfors Liou, Modelling radiative challenging research, complex, heterogeneous non-randomly distributed array absorptive surfaces, unlike atmospheric particles (Durand Nevertheless, expanded simulate then function. library models, libRadtran (Emde 2016), accounts scattering H2O, O3, O2, CO2, NO2 aerosols angle, forth, suited (Mayer, Mayer Kylling, Validating spectrometer let changing environment. Hence, developed, circumvents exhaustive irradiance. coupled data database Kotilainen, 2018 [dataset]) put accessible interface https://agronomous.shinyapps.io/spectramap/ possible consumption, chemicals. natural-light trade-offs production. impact placed framework disparate aspects technology combined. For track local regional patterns, external back regulation lights anticipate requirements. By utilising internet things, sensor centralised database, implementing remotely 3). initially too expensive implement outside industrial-scale automation continued innovation drive time, apps mobile phones trickle Large solutions Currently, diffusive coatings, spectrally selective, seasonally avoid acute short-term conditions. Whereas, automatically deployed change, well-calibrated maintained function effectively (Berruto 2008; Hernandez more-elegant solution coordination pollination, open Technical eventually employment actively levels (Baeza differential lighting. We highlighted under-exploited modify achieve monitoring, sciences ecophysiology business matching managed Selecting complemented strategic deployment technology. Maximising footprint work funded Academy Finland grants T.M.R., #304653 #324555. authors no conflict interest declare. paper conceived T.M.R. T.K.K. written T.M.R.; figures were M.D., M.P. P.J.A. edited text approved final version. Data sharing applicable—no generated. Figure S1 alter Left column normal photos showing right UV-A. photographed shortwave side walls UV-transparent Plexiglas, ventilation three creates overlaid complex Please note: publisher functionality any supporting supplied authors. Any queries (other missing content) directed corresponding author article.