Effect of air-circulating and condensation dehumidification inside greenhouse in South China.

Taking plastic-mulch coverage greenhouses with steel-frame arch for experient greenhouses,three treatments including air-circulating condensation dehumidification,plastic-mulch coverage dehumidification and control were orranged,and the effect of dehumidification was studied.The results showed that:on the sunshine,air relative humidity inside three different treatment greenhouses and outdoor were all at the lowest point in the 14:00-15:00;and changed smoothly from 19:00 to 10:00,showing for the outdoor condensation coverage control,air relative humidity of upper level,middle level and lower level of the condensate greenhouse were lower than 2.7%-10.5%,2.0%-7.5% and 2.4%-11.3% respectively compared with that of the control.Air absolute humidity of condensation was the smallest among three treatment,and showed vertical variation of the upper the middle the lower.In the cloudy sky and rain,air relative humidity values was showed control ≥condensation coverage,and the margin is very small.In January,air relative humidity inside greenhouses showed control coverage condensation,and with the largest changing range on the sunshine and smaller in the cloudy sky and rain;air absolute humidity inside greenhouses showed control coverage condensation on the sunshine and control condensation coverage in the cloudy sky and rain.