Moisture Balance Model for Soil Evaporation Estimation in the Greenhouse Airspace in Cold Regions

Abstract

<abstract><title>Abstract.</title> Greenhouse in cold regions easily experiences high levels of relative humidity, especially from April to October, which leads to plant diseases and reduce quality and yields. Several methods can be applied for greenhouse dehumidification, including the use of heat exchangers, mechanical refrigeration dehumidifiers, exhaust fans, etc. The dehumidification requirement needs to be estimated in order to size the dehumidification equipment. Some moisture balance models were developed to estimate plant transpiration, condensation, and ventilation, and then determine the greenhouse dehumidification requirement; however, none of them took soil evaporation into account. In this study, the soil evaporation was estimated using a moisture balance model based on the experiment conducted in a commercial greenhouse from April to June 2013. The main conclusion is that the simulating results reveals that the soil evaporation was the main contribution to the greenhouse moisture air, especially during the nights. Further research should be conducted to quantify the soil evaporation inside the greenhouse in order to determine the dehumidification requirement more precisely.