The evapotranspiration is a component of the water balance constituting a major challenge in its quantification. The complex physical processes involved in its effective determination on a large scale have spurred scientists to often make use of empirical equations, which have inherent limitations with regard to their applicability as descriptors of the evapotranspiration behavior in different regions across the world. This study was performed for the Campos dos Goytacazes region, in Rio de Janeiro state. It is proposed to investigate and to evaluate the performance of six empirical equations in contrast to FAO56-Penman-Monteith equation. The results indicated that the differences observed between the values obtained using the empirical models applied in this study and the values calculated by the FAO56-Penman-Monteith equation were greater than 10%, which means an error of about 0.5 mm.day-1.

Temperature monitoring is an important procedure to control the composting process. Due to cost limitation, temperature monitoring is manual and with daily sampling resolution. The objective of this study was to develop an automatic station with US$ 150 dollars, able to monitor air temperature at two different points in a compost pile, with a 5-min time resolution. In the calibration test, the sensors showed an estimated uncertainty from ± 1 to ± 1.9 ºC. In the field validation test, the station guaranteed secure autonomy for seven days and endured high humidity and extreme temperature (> 70 °C).