EFFECTS OF VAPOUR PRESSURE DEFICIT AND RADIATION ON THE TRANSPIRATION RATE OF A GREENHOUSE SWEET PEPPER CROP

J.C. Gázquez, J.C. López, E. Baeza, J.J. Pérez-Parra, M.D. Fernández, A. Baille, M. González-Real
The effects of air vapour pressure deficit (VPD) and radiation reduction by whitening on the transpiration rates of a greenhouse sweet pepper crop (transplanted in July) under a semi-arid climate (Almería, south-eastern Spain) were studied. Measurements were carried out during ontogeny in three analogue multi-span curved greenhouses: (i) without air VPD control and no whitening ii) with a fog-system operating when air VPD was higher than 1.5 kPa and iii) without air VPD control and with whitening (about 30% reduction in greenhouse solar radiation transmission). Leaf transpiration vs. inside solar radiation, air VPD and leaf area index were studied and analysed. A model has been developed (multiple regression analysis), based on the simplified Penman-Monteith formula, between the measured transpiration rate and the radiative and advective components, equation: λE = A f1(LAI)Rg + B f2(LAI)VPD, which for different conditions of air VPD and inside radiation, gave a good prediction of the hourly water consumption. This simplified transpiration model can be used to manage irrigation with different conditions of VPD and incoming radiation.
Gázquez, J.C., López, J.C., Baeza, E., Pérez-Parra, J.J., Fernández, M.D., Baille, A. and González-Real, M. (2008). EFFECTS OF VAPOUR PRESSURE DEFICIT AND RADIATION ON THE TRANSPIRATION RATE OF A GREENHOUSE SWEET PEPPER CROP. Acta Hortic. 797, 259-265
DOI: 10.17660/ActaHortic.2008.797.36
https://doi.org/10.17660/ActaHortic.2008.797.36
irrigation control, ventilation, fan ventilation, fog-system, whitening, lysimeter
English

Acta Horticulturae