Abstract
Glasshouse films with adjustable light transmittance and energy-efficient designs have the potential to reduce (up to 80%) the high energy cost for greenhouse horticulture operations. Whether these films compromise the quantity and quality of light transmission for photosynthesis and crop yield remains unclear. A “Smart Glass” film ULR-80 (SG) was applied to a high-tech greenhouse horticulture facility, and two experimental trials were conducted by growing eggplant (Solanum melongena) using commercial vertical cultivation and management practices. SG blocked 85% of ultraviolet (UV), 58% of far-red, and 26% of red light, leading to an overall reduction of 19% in photosynthetically active radiation (PAR, 380–699ÃÂ nm) and a 25% reduction in total season fruit yield. There was a 53% (season mean) reduction in net short-wave radiation (radiometer range, 385–2,105ÃÂ nm upward; 295–2,685ÃÂ nm downward) that generated a net reduction of 8% in heat load and reduced water and nutrient consumption by 18%, leading to improved energy and resource use efficiency. Eggplant adjusted to the altered SG light environment via decreased maximum light-saturated photosynthetic rates (Amax) and lower xanthophyll de-epoxidation state. The shift in light characteristics under SG led to reduced photosynthesis, which may have reduced source (leaf) to sink (fruit) carbon distribution, increased fruit abortion and decreased fruit yield, but did not affect nutritional quality. We conclude that SG increases energy and resource use efficiency, without affecting fruit quality, but the reduction in photosynthesis and eggplant yield is high. The solution is to re-engineer the SG to increase penetration of UV and PAR, while maintaining blockage of glasshouse heat gain.
Original language | English |
---|---|
Article number | e245 |
Number of pages | 18 |
Journal | Food and Energy Security |
Volume | 9 |
Issue number | 4 |
DOIs | |
Publication status | Published - 2020 |
Open Access - Access Right Statement
© 2020 The Authors. Food and Energy Security published by John Wiley & Sons Ltd on behalf of Association of Applied Biologists. This is an open access article under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits use, distribution and reproduction in any medium, provided the original work is properly cited.Keywords
- eggplant
- energy
- greenhouses
- light
- photosynthesis