Suitability evaluation of four methods to estimate leaf wetness duration in a greenhouse rose crop
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Resumo
A water-film above the leaf surface is a necessary condition for the start of
the infective process of many pathogens. Therefore, the Leaf Wetness Duration
(LWD) has a strong relationship with the development and outbreak of plant
diseases. The occurrence of free water on leaf surfaces is a common situation for the
simple plastic greenhouses used to grow ornamental crops in the Bogota Plateau
(Colombia). The objective of this work was to evaluate the suitability of four models
to predict LWD occurrence in a greenhouse rose crop. Model performances were
compared against the measurement of dielectric leaf wetness sensors, placed at 1.2
and 1.8 m above the ground, within two sampling locations inside a greenhouse
during a 25-day period. Sensors were connected to dataloggers, programmed to
store data every 10 min. Two copper-constantan thermocouples measured air and
wet-bulb temperature and were used to calculate relative humidity (RH). Three
empirical models were evaluated: Constant RH threshold (RH≥90%), locally
calibrated RH threshold (RH≥94%) and dew point depression (DPD). Also, one
physical model that estimates LWD based on the latent heat flux (LE) of the leaf was
considered. As a result the following four scores were calculated: fraction of correct
estimates, correct success index, false alarm ratio and bias. LWD estimated at 1.8 m
above the ground showed the best performance for all the empirical models whereas
the physical model yielded the best results for measurements made at 1.2 m. The
results obtained with the models indicated a differential degree of success for the
prediction of LWD. In general, RH and DPD with thresholds of 94% and 2°C
respectively were the most suitable models to estimate LWD, resulting in higher
precision and accuracy. The results will contribute to the development of integrated
pathogen management in greenhouse rose crops in the Bogota Plateau.
Palabras clave
Energy balance; Relative humidityLink para o recurso
https://www.actahort.org/books/893/893_87.htmCollections
- Año 2011 [102]
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