According to a new study carried out in Spain, the majority of greenhouses in the Mediterranean basin have very inefficient ventilation systems, aggravated by insect screens over air vents that act as a physical barrier to air circulation, leading growers to resort to simple, but inefficient cooling methods.
Greenhouse implemented with interior mobile shading
Report authors the Andalusian Institute for Research and Training for Agriculture’s greenhouse unit (IFAPA) and shading technology specialist Svensson found that whitewashing caused considerable yield losses as a result of a shortage of sunlight reaching crops.
In fact, researchers found that the reduction in light transmission occurred during the entire day, even during periods (morning and afternoon) when shading would not be necessary.
However, by using dynamic or active shading systems as an alternative to the quick fix of whitewashing the study revealed that growers can achieve an increase in yields of up to 25%.
Shading systems react to the temperature and the intensity of the sunlight entering the greenhouse, meaning that effective protection for crops can be provided at the hottest times of the day particularly around noon when temperature and humidity reach harmful levels for plants.
Higher yields
The joint study carried out by Svensson and IFAPA at the institution research centre in La Mojonera, Almería1 looked at the performance of the Harmony mobile screen during the spring-summer 2013 tomato season, examining the effect on the greenhouse climate and tomato yield.Detail of the crop in full production
As part of the project, one greenhouse was equipped with a mobile shading screen while a whitewashing was applied to a second facility.
Researchers found over the course of the study2 that plants in the greenhouse using the shading system received 27.9% more sunshine than the whitewashed facility, with the yield in the mobile shaded greenhouse higher during the whole harvesting period.
Overall, the report revealed that the tomato yield in the greenhouse using the Harmony mobile screen was 25% higher during the season than the whitewashed greenhouse, with 12.4 more fruits harvested per metre squared.
The study concluded that using the mobile shading system during the central hours of the day – when temperatures can exceed safe levels for crops – delivered higher precocity and an increase in the tomato yield compared with traditional whitewashed greenhouses.
For more information
Ludvig Svensson BV
Dasha Koptina
+31 181 39 26 66
dasha.koptina@svenssonglobal.com
IFAPA (Centro La Mojonera)
Dr Pilar Lorenzo Minguez
+34 950156453
mojonera.ifapa@juntadeandalucia.es