The objective of this study was to estimate the duration of wetness by dew (DWW), from 18 to 06 h, using two empirical models: a) number of hours with relative air humidity > 97% (NHUR > 97%) and b) depression of the dew point < 0.5 °C (NHDPO < 0.5 °C). A meteorological station was placed in a cocoa plantation at Camacan Bahia, Brazil, in which data were collected for air temperature (tar) and relative humidity (UR). These data were used for calculations of the partial pressure, vapor saturation and temperature of the dew point (to). The depression of the dew point (DWP) was obtained by the difference between to and tar. With the hourly data of UR and DWP the models were established for estimating DWW. The choice of the best model was based on the statistical indexes of precision and accuracy. It was observed that DWW occurred, on average most of the days (> 61%), although the percentage for winter and summer months was 80.8 and 15.8% respectively. The high statistical indexes observed here show the viability of the models for estimating, with high precision, the DWW in a cocoa ecosystem. The models are of easy application and operation, dispensing the utilization of sensors and of more complex methods. Howerer, they still need some adjustments to be used for other crops and conditions.
cocoa tree; microclimate; temperature of the dew point air; relative humidity
