Optimisation of the irradiation dose and duration factors in conditions of lettuce-and-leaf vegetable photo-culture matches the goals of development of controllable plant cultivation systems for greenhouses and other protected-ground facilities. Based on the literature of the last years, it is specified that the DLI (Daily Light Integral) factor is paid great attention to in development of sustainable industrial phyto-technology with use of online meteorological and satellite-navigation data. The opportunities of control of the factors under consideration are demonstrated through the example of the author’s experiment in photo-culture conditions of two lettuce cultivars (Frisee and Adamant) made using an automated multi-layer City Farm installation in a room with controlled environment. During the experiment, the variable values of PPFD (photosynthetic photon flux density) in range (180–220) μmol/(m2s), daily photoperiod τф from 13 to 21 hours, vegetation duration t about 24 to 30 days were used with constant VLI, which is the new concept of vegetation light integral (VLI), was introduced similarly to DLI. It is found that the principle of reciprocity of irradiance parameters and time (the Bunsen-Roscoe law) is not met at constant dose. In terms of average producing capacity, it was possible to increase the level of biomass synthesis by 30 % for Frisee lettuce and by 36 % for Adamant lettuce. A series of partial dependences relating producing capacity of lettuce cultivars to DLI, photoperiod, and vegetation duration was obtained (the authors understand producing capacity as biomass over the vegetation period).
The experiment results may be used as input data for the Virtual Agronomist software developed for controlled plant cultivation.
1. Prikupets, L.B., Boos, G.V., Terekhov, V.G., Tarakanov, I.G. Studying of the Affects of Radiation in Different Ranges of PAR Region on Capacity and Biochemical Composition of Biomass of Lettuce and Leaf Vegetables [Issledovaniye vliyaniya izlucheniya v razlichnykh diapazonakh oblasti FAR na produktivnost i biokhimicheskiy sostav salatno-zelennykh kultur] // Svetotekhnika, 2018, # 5, pp. 6–12.
1.a. Prikupets, L.B., Boos, G.V., Terekhov, V.G., Tarakanov, I.G. Research into influence from different ranges of PAR radiation on efficiency and biochemical composition of green salad foliage biomass // Light & Engineering, 2018, Vol. 26, # 4, pp. 38–47.
2. Prikupets, L.B., Boos, G.V., Terekhov, V.G., Tarakanov, I.G. Optimisation of Light Engineering Parameters of Lettuce and Leaf Vegetables Photoculture Using LED Emitters [Optimizatsiya svetotekhnicheskikh parametrov pri svetokulture salatno-zelennykh rasteniy s ispolzovaniyem svetodiodnykh izluchateley] // Svetotekhnika, 2019, # 4, pp. 6–13.
2.а. Prikupets, L.B., Boos, G.V., Terekhov, V.G., Tarakanov, I.G. Optimisation of lighting parameters of irradiation in light culture of lettuce plants using LED emitters // Light & Engineering, 2019, Vol. 27, # 5, pp. 43–54.
3. Chub, V.V., Mironova, O. Yu. Light Absorption by Plants and Bioactive Molecules [Pogloshcheniye sveta rasteniyami i biologicheski-aktivnyie molekuly] // Svetotekhnika, 2019, Special issue, pp. 13–18.
4. The importance of DLI and Light Quality, Agro Tech Tomorrow Online Trade Magazine, 11.09.21.
5. Runkle, E., DLI Requirements, Greenhouse product news, May, 2019
6. Tikhomirov, A.A., Ushakova, S.A., Shikhov, V.N., Shklavtsova, E.S. The Conceptual Approaches to Selection of Lamp Radiation Spectra for Plant Cultivation in Artificial Conditions [Kontseptualnyie podkhody k vyboru spektra izlucheniya lamp dlya vyrashchivaniya rasteniy v iskusstvenykh usloviyakh] // Svetotekhnika, 2019, Special issue, pp. 19–23.
6.а. Tikhomirov, A.A, Ushakova, S.A., Shikhov, V.N., Shklavtsova, E.S. Conceptual Approach to Selecting Radiation Spectrum of Lamps for Plant Cultivation // Light & Engineering, 2019, Vol. 27, # 6, Special Issue, pp. 24–30.
7. Faust, J.E., Logan, J. Daily Light Integral: A Research Review and High-resolution Maps of the United States. American Society for Horticultural Science, Sep, 2018.
8. Sollum unveils new features for its service cloud platform. Hortibiz Daily, 8.10.21.
9. Terekhov, V.G. Lighting System for a City Farm Automatic Multi-Layer Phyto-installation [Sistema osveshcheniya dlya avtomatizirovannoy mnogoyarusnoy fitoustanovki tipa City Farm] // Svetotekhnika, 2019, # 5, pp. 59–63.
9.а. Terekhov, V.G. Irradiation System for a City Farm Automated Multi-Layer Phytoinstallation // Light & Engineering, 2019, Vol. 27, # 6, pp. 106–111.
10. Virtual Agronomist Article. Certificate of Deposit with the KOPIRUS Reproduction Rights Organisation No. 020–010894 dated November 25, 2020.
11. Terekhov, V.G. Virtual Agronomist–the Cutting-Edge IT Technologies Go to the Aid of Greenhouse Facilities [Virtualniy agronom – peredovyie IT-tekhnologii idut na pomoshch teplichnym kompleksam] // Teplitsy Rossii, 2022, Vol. 1, pp. 22–25.
12. Rakutko, S.A., Rakutko, E.N. The Dependence of the Leaf Area of Lactuca sativa L. on the Radiant Flux Dose and its Components [Zevisimost ploshchadi listyev salata Lactuca sativa L. ot dozy potoka opticheskogo izlucheniya i eyo sostavlyayushchikh] // Bulleting of the Saint-Petersburg State Agrarian University, 2018.
13. Golovko, T.K., Dalke, I. V., Grigoray, E.E., Butkin, A.V., Tabalenkova, G.N. Protected-Ground Vegetable Cultivation in the North [Ovoshchevodstvo zashchishchyonnogo grunta na Severe], Syktyvkar, 2017, 156 p.

• Previous article

• radiation
• photosynthetically active radiation (PAR)
• photo-culture
• multi-layer phyto-installation (MPI)
• irradiance
• photosynthetic photon flux density (PPFD)
• DLI
• VLI
• photoperiod
• vegetation period
• reciprocity
• controllable plant cultivation