Chis Plackett, FEC
James Bean, Crystal Heart Salads
Neal Wright, Micropropagation Services
Simon Budge, BHTA representative
Colin Frampton, Consultant
Steve Carter, Ornamentals
Geoffrey Smith, Mapleton Growers
AHDB Horticulture Cost: £69,327
Light is the primary driver of crop growth and ultimately yield. In greenhouse production, growers have a unique opportunity to modify the light environment for commercial gain. Many control light input via the use of supplementary lighting, including LEDs and the use of spectral filters within glazing materials. Despite these opportunities, the responses of whole plants to spectral quality are not fully understood. A clear acid test is that manufacturers and users (growers) of LEDs do not have clear guidance on which spectral output to design / select. This is despite large volumes of data on plant light responses to spectral quality. However, much of this literature does not describe whole plant responses, it tends to focus on specific physiological mechanisms. As yet, there have been no attempts to synthesise this data into an overall quantitative model describing how whole plants respond to light spectral quality. Such a model would help describe the optimal action spectra required by a crop and how it changes with phenology. It would synthesise at a whole plant level our known understanding of key physiological responses to light, including impacts on crop photosynthesis, phenology and photomorphology. Such a framework would be of significant interest and benefit to growers. It could be applied to develop optimise lighting systems (LED’s and spectral filters) and crop responses. The student will develop the model by applying data from a widescale meta analysis of existing published sources and validate it using data from AHDB funded research on plant light responses at Stockbridge Technology Centre and during a study period at Michigan State University.
Benefits to Industry:
This project will fundamentally underpin our understanding of the effects of light quality on a wide range of greenhouse crops. This will directly support the development, design, roll out and selection of LED systems by lighting designers and in particular UK growers. LED’s are seen as a key driver for driving crop yield in the next 5 to 10 years. They offer unprecedented energy efficiency combined with an opportunity for them to generate highly specific spectral wavebands. To give an insight into the impact of lighting systems, in the NL high pressure sodium lighting systems consume 7% (c. 7.6TWh) of the entire nations electrical load (Wageningen UR, Greenhouse energy monitoring report 2013). Electrical comsumption for assimilation lighting now represents 1/3rd of the entire energy cost of production in the Dutch electricity sector. In NL, energy in totality represents 16 to 25% of total production costs in crops such as tomatoes. It has a key and fundamental impact on the economic sustainability of the sector. No equivalent figures are available for the UK, but costs per grower will be analogous to those in NL. It is clear therefore that to drive the economic and environmental sustainability of the greenhouse sector, growers need to increase the efficiency of energy resources to crop demands. Understanding crop and plant spectral responses will be key to the development of energy efficient lighting strategies. Lighting systems can also be developed with spectral outputs optimised to crop needs. Moreover the development of improved greenhouse cladding materials through knowledge of crop spectral responses is an entirely passive technology. Growers could gain increased productivity and quality benefits without additional energy inputs.
The use of light in horticulture is a fundamental and underpinning driver for productivity, this studentship will train a graduate to a PhD level and be able to engage at a high level with the research and industrial community. The skills developed will help underpin a career in a key segment of the horticulture knowledge base.