TRANSPIRATION OF GLASSHOUSE ROSE CROPS: EVALUATION OF REGRESSION MODELS
Regression models of transpiration (T) based on global radiation inside the greenhouse (G), with or without energy input from heating pipes (Eh) and/or vapor pressure deficit (VPD) were parameterized.
Therefore, data on T, G, temperatures from air, canopy and heating pipes, and VPD from both a lysimeter experiment and from a cut rose grower were analyzed.
Based on daily integrals, all T models showed good fits due to the dominant effect of global radiation G (solar + supplementary radiation) inside the greenhouse on T. Similar G-T relations on high-light and low-light days indicated identical effects of solar radiation and radiation from supplementary light on T.
For both data sets, similar regression coefficients of 0.3 l/MJ were obtained with models including G and VPDair, G and Eh, or G and a constant intercept.
Including the difference between saturated pressure at leaf temperature and air vapor pressure (VPDleaf-air) did not improve the regression models.
G accounted for 74% of latent heat transfer.
The contribution of heating underneath the canopy on T was investigated by switching off the heating on days during the winter period, and was on average 13% or 0.2 l/m².day for an extra energy input by heating pipes of 3 MJ/m².day.
Therefore, the efficiency of sub-canopy heating was smaller than 0.07 l/MJ, less than 23% of the efficiency of global radiation.
Baas, R. and van Rijssel, E. (2006). TRANSPIRATION OF GLASSHOUSE ROSE CROPS: EVALUATION OF REGRESSION MODELS. Acta Hortic. 718, 547-556
DOI: 10.17660/ActaHortic.2006.718.64
https://doi.org/10.17660/ActaHortic.2006.718.64
DOI: 10.17660/ActaHortic.2006.718.64
https://doi.org/10.17660/ActaHortic.2006.718.64
global radiation, heating, lysimeter, supplementary lighting
English