High tunnel production systems improve yields and fruit size of sweet cherry
Intensive sweet cherry production in tunnel covered orchard systems offer an advantage of reducing rain-induced fruit cracking. In May 2005 four Haygrove multibay tunnel systems were installed on a gentle slope at the experimental farm at Bioforsk Ullensvang, western Norway. In these tunnels, feathered 1-year-old sweet cherry 'Sweetheart'/Colt trees were planted with two rows at a spacing of 2×4 m in each tunnel. Each tunnel was split into two halves and covered from the end of April to beginning of September with one of two different plastic covers, having different light spectral transmittance; Luminance THB film (absorbing infrared light) and traditional Visqueen clear UV polythene film. Climatic parameters were monitored inside and outside the tunnels from the beginning of May to the beginning of September each year and yield data and fruit quality parameters were recorded. In 2009, from May 7 to September 16 the average temperature measured outside the tunnels was 14.3°C. Temperatures exceed 25°C only on two days. Temperatures inside the tunnels were 0.3°C higher on average during the entire season but exceeded 30°C on the same two hot days. Temperatures under the Luminance film were slightly lower compared to the clear film and especially reduced the temperature build up on sunny days. The harvest period was the second half of August. Average yield tree-1 was 8.8 kg (11 t ha-1) in the fourth leaf and 18.8 kg (23.5 t ha-1) fifth leaf. There were no yield differences between the two different films. Fruit size measurements found that 80% of the fruits were larger than 30 mm in diameter in the fourth leaf and 51% in the fifth leaf. Total soluble solid content was generally high (17-18%) and no significant differences were found between the different films.
Meland, M., Frøynes, O. and Kaiser, C. (2017). High tunnel production systems improve yields and fruit size of sweet cherry. Acta Hortic. 1161, 117-124
Prunus avium L., protected environment, fruit quality, covering length, high density orchard, Luminance THB film, Visqueen clear UV