Temperature depression while aerating moist soils and the resultant effect on maize seedling growth

Summary Moist soil surfaces were aerated with air at relative humidities from 4 to 100%, flowing at rates from 0.07 to 3.5 liters per min. Evaporation occurred and resulted in measureable depressions of soil temperature when the aerating air was less than 100% saturated with water vapor and flowing at rates above 0.1 liter per min. Growth of young maize seedlings was markedly affected by depressed soil temperatures when the aerating air was at 30% relative humidity and flowing at 3.0 liters per min. Growth was affected even though the soil containers were submerged in constant temperature water baths to help maintain the uniformity of soil temperature. In containers similar to those used in this study, plant growth would be affected by aerating soils with air that is less than saturated with water vapor and is flowing at rates as low as 0.5 to 1.0 liter per min. On the other hand, plant growth would probably not be affected when aerated even with very dry air flowing at rates below about 0.1 liter per min.