IMPROVING ENERGY EFFICIENCY IN PROTECTED CROPPING BY EXPLOITING PLANT RESPONSES TO SOLAR ULTRAVIOLET RADIATION

Lead Research Organisation: Lancaster University
Department Name: Lancaster Environment Centre

Abstract

Horticulture, the production of fresh fruit, vegetables, salads etc, is often overlooked in discussions of food security yet is vital to avoid hidden hunger due to shortage of micro-nutrients. Delivering a year-round supply of fresh produce for N Europe involves local crops produced in heated glasshouses, or crops imported from the Mediterranean basin and beyond. In either case, energy is a major commercial constraint (costs and C footprint) and any technology that reduces energy use is immediately attractive, commercially and environmentally. This project addresses this energy challenge in protected cropping by delivering fundamental insights into a newly recognized crop response to the ultraviolet (UV) radiation in sunlight.

Previous research at Lancaster contributed to the development of new UV-transparent (UV-T) crop-covers used in protected crops. Growers using UV-T cladding report that crops mature earlier than under conventional cladding, and they attribute this to the crop being warmer under UV-T covers. We have tested this and shown for the first time that additional UV exposure within a physiologically relevant range results in small but significant increases (0.5-1.7C) in leaf temperature. This is caused by UV decreasing stomatal conductance and transpirational cooling, thereby warming the leaves. This CASE studentship will investigate this effect of UV on crop temperature in a range of commercial protected crops, both fruit crops (e.g. strawberry, tomato, pepper, cucumber) and leafy crops (e.g. basil, coriander, lettuce, rocket). The student will go on to investigate in selected crops whether UV during the day also affects crop temperature at night, and whether effects are confined to leaves, or also occur in other tissues.

Arid's commercial assessment is that objective scientific evidence that UV-T covers leads to increased crop temperature would be highly attractive to growers, especially for early and late crops in the Mediterranean rim. The new understanding obtained through the project will also inform the design of new energy saving claddings. In the longer term, this understanding may also allow improved energy use in crops lit by LEDs.

The project will start at Lancaster (Years 1 & 2) studying temperature and physiological responses in a range of crops (as above). During Years 3 or 4 the student will spend at least six months placement at Arid's base in Antalya, Turkey. We believe an international dimension is essential for understanding the complexities of modern commercial protected crop management. Also, the impact from this project will most likely be applied most quickly in the environments like Turkey, where any temperature benefit would be a major commercial advantage for UK-manufactured UV-transparent plastics.

This collaboration between Arid Agritec and LEC provides an immediate opportunity to field test academic findings at commercial field sites. The collaboration also provide the student with a unique opportunity to undertaken research across the range of scales (laboratory, glasshouse, field) and different research environments, and with an obvious, immediate route to exploitation.

The student will have contact with a range of agri-business professionals, including growers, technicians, consultants and supply chain personnel. Such interactions will ensure the student understands the needs of the industry, and provide training in business strategy. That understanding will be underpinned at Lancaster by formal skills training consistent with the Researcher Development Statement developed by Vitae. The student will also benefit from a supervisory team (Prof Nigel Paul and Dr Ian Dodd at Lancaster, Dr Jason Moore at Arid) with a total of 60 years research experience in plant science across the academic-commercial spectrum. These are important contexts for the development of the student's wider skills base as well as for the successful commercialization of their research.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
BB/M017109/1 01/10/2015 30/09/2019
1653788 Studentship BB/M017109/1 01/10/2015 30/09/2019 Tom Williams
 
Title Antalya (Turkey) polytunnel dataset 
Description Data collected on leaf temperature, stomatal conductance, transpiration rate, assimilation rate, intracellular carbon dioxide (with instantaneous water use efficiency calculated from these) with a LI-6400 (LI-COR), also leaf temperature day & night (infrared thermometer), and leaf thickness growth rate and stem elongation rate , in custom made polytunnels to assess the response of tomato (cv. Money Maker) to solar UV radiation over 1 week. 3x polytunnels were clad in UV blocker plastic and 3x polytunnels in UV transparent plastic cladding. After 1 week some plants (others remained as a control) were swapped into the opposite UV treatment polytunnel (i.e. from UV blocker to UV transparent) and the same parameters measured 24 hours later to determine the effect of 'transfer' between UV environments. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? No  
Impact None, no response detected because UV radiation levels were insufficient. 
 
Title Climate cabinet dataset 
Description Data collected with LI-6400 infrared gas analyser (LI-COR) in a Snijder climate cabinet to assess the dose response of tomato (cv. Money Maker) to UV radiation applied at various different irradiances for 90 mins. Data collected on leaf temperature, stomatal conductance, transpiration rate, assimilation rate, intracellular carbon dioxide and subsequent calculation of instantaneous water use efficiency. 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? No  
Impact Allowed determination of the UV dose response relationship in terms of the above mentioned parameters. 
 
Title LEC polytunnel dataset 
Description Data collected with a porometer (stomatal conductance,) infrared thermometer and thermal camera (leaf temperature) in custom made polytunnels to assess the response of tomato (cv. Money Maker) to solar UV radiation over 1 week and on a single night. 2x polytunnels were clad in UV blocker plastic and 2x polytunnels in UV transparent plastic cladding. After 1 week some plants (others remained as a control) were swapped into the opposite UV treatment polytunnel (i.e. from UV blocker to UV transparent) and data collected with a LI-6400 (LI-COR) on leaf temperature, stomatal conductance, transpiration rate, assimilation rate, intracellular carbon dioxide and subsequent calculation of instantaneous water use efficiency, 24 hours later to determine the effect of 'transfer' between UV environments. This was repeated 4 times. 
Type Of Material Database/Collection of data 
Year Produced 2018 
Provided To Others? No  
Impact A clear trend of reduced stomatal conductance and increased leaf temperature was observed but was not statistically significant. 
 
Description Photobiology Workshop (Lancaster University) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Academics, business people and students, from as far away as London and Middlesbrough, gathered at the Lancaster Environment Centre (LEC) on the afternoon of the 6th February for the N8 Agrifood-sponsored workshop Lighting the Way to Resource Use Efficiency, which showcased different technologies for manipulating the light environment which crops are exposed to. International visitors from Pennsylvania State University (USA) and Cukurova University (Turkey) were able to join the meeting via video-conference. The workshop was held as part of an N8 Local Pump-Priming Award made by Lancaster University, to foster collaboration with the University of Liverpool and Stockbridge Technology Centre (Yorkshire).
Following a brief introduction by host Professor Ian Dodd (LEC), Professor Nigel Paul (LEC) provided a historical perspective on light manipulation in cropping systems, with projections into the future. Drawing on his archives of previous research, he convinced the audience of his ability to accurately predict the future use of light-emitting diodes (LEDs) in protected horticulture (give or take 5 years). A highlight was his video of "aphids dancing" in response to UV exposure.
Dr Miguel de Lucas Torres (Durham) providing a fascinating insight into the molecular mechanisms by which plants perceive lighting cues, with changes in gene expression orchestrated by transcription factors and nuclear chromatin modification. Dr Rhydian Beynon-Davies (Stockbridge) showcased results from some of the unique lighting facilities at his site, demonstrating that light's influence extends below-ground, with substantial modification of rooting patterns (and transplant success) when seedlings are exposed to light regimes of different spectral quality.
Dr Kathleen Demchak (Pennsylvania) reported the initial results of the TunnelBerries project, which uses different plastic claddings to manipulate the light environment berry crops are exposed to. In addition to effects on crop yields and quality, certain claddings reduced the levels of some insect pests to manageable levels in the absence of pesticide applications. Dr Wagdy Sobeih (Arid Agritech) also discussed his company's ambitions to develop new plastic claddings to best suit specific crops, based on a wealth of experience in commercial protected horticulture in the Middle East, where increasing crop water use efficiency is a priority for growers.
Following enthusiastic discussion at the coffee break (with cakes the colour of some of the light regimes previously discussed !), the audience reconvened for the Practising Photobiologists session, allowing Lancaster-registered research students to briefly present their work:
Tom Williams outlined his research on UV effects on leaf gas exchange of tomato crops
Phoebe Sutton discussed her work with MayBarn Consultancy on developing bespoke lighting regimes for high value herbs
Hao Zhou presented his measurements of crop yield, gas exchange and volatile emissions, collected during his research placement at Stockbridge last summer, while a student at the University of York.
Several discussion points were considered in the closing remarks, with informal discussions suggesting sufficient interest in a follow-up meeting in Durham next year.
While resource use efficiency may be only one aspect that growers consider when developing horticultural cropping systems, it became apparent they could have their cake and eat it too - with increased yields, decreased costs and increased resource use efficiency all achievable following sufficient research.
Year(s) Of Engagement Activity 2019