Abstract

Greenhouse heating during cold seasons is costly as it is high energy-consuming. The use of latent heat stored during sunny periods for greenhouse heating could be an interesting alternative in several regions worldwide as in Tunisia. Thus, new agronomic/climatic approaches were developed to produce several crops such as tomato (Lycopersicum esculentum L.) in a sustainable way. In this context, the growth, photosynthesis, yield and quality of tomatoes cultivated inside a greenhouse equipped with a new solar air heater with latent storage (IGLHS) were studied in comparison to an unheated greenhouse (IG). Using the solar air heater, the night recovered heat reached 30% of total heating requirements. Consequently, IGLHS microclimatic conditions positively affected plant growth and physiology and led to an early fructification and an increased yield as compared to the unheated greenhouse. Besides, fruit quality evaluation allowed observing significant increases in the lycopene, phenolics, flavonoids and tannins contents (61%, 57%, 63% and 54%, respectively) under IGLHS conditions. The solar air heater collector revealed to be an efficient competitive system enhancing early maturity, leading to increased tomato yields and reducing considerably greenhouse heating costs as it utilizes a highly solicited natural renewable energy.

Keywords: Greenhouse; Growth; Heat; Photosynthesis; Renewable energy; Tomatoes