Abstract: The prefabricated solar greenhouse has the tendency to replace the traditional greenhouse in the protected cultivation in China. The prefabricated solar greenhouse with double membrane and double insulation cover is one of them. But studies on microclimate of such greenhouses are lack. Therefore, the study of the microclimate in this kind of greenhouse is necessary, which can provide the basis for cultivation and management. The tested greenhouse is located in Zhengzhou, Henan province. Temperature, ground temperature at −0.1m（0.1m depth underground）, relative humidity and illuminance were measured both inside and outside the tested greenhouse. There are three recorders in the greenhouse, one 10m from the east wall, one 50m from the east wall and one 10m from the west wall, and there is also a 10m away from the southern greenhouse. The test period was from Nov.1, 2020 to Feb.28, 2021. The results showed that the ten-day average air temperature was 11.4−21.4℃, and the ten-day average of daily minimum air temperature was 9.4−16.7℃ in the greenhouse. The ten-day average temperature of soil temperature at 0.1m depth was 15.4−22.9℃, and the ten-day average of daily minimum soil temperature at 0.1m depth was 15.7−21.1℃ in the greenhouse ,and the max air temperature and soil temperature difference between indoor and outdoor was 17.0℃ and 15.6℃. During the coldest January late of the test, the ten-day average of daily minimum air temperature and soil temperature at 0.1m depth was 7.9℃ and 2.2℃. Ten-day average of daily minimum air temperature and soil temperature at 0.1m depth greenhouse was 9.9℃ and 15.8℃. The illuminance in the greenhouse increased gradually in the whole period. The typical sunny days illumination changed between 2000−22000lx, and average light transmittance were 42%, 52%, 49% and 45% in the greenhouse. The light transmittance existed obvious differences between each month, which was highest in December. The typical cloudy days illumination change between 300−4000lx and average light transmittances were 34%, 35%, 36% and 33% in the greenhouse, when light transmittance was not obvious difference between each month. The relative humidity was relatively high and was close to 100% at night in the greenhouse. The relative humidity is 95.4%−99.0%, and the proportion of the duration of leaf condensation is 89.1%−99.5% at night from late-Nov. 2020 to late-Jan. 2021. Come to a conclusion, the prefabricated solar greenhouse with double film and double insulation structure cover has better thermal insulation performance, and it can be used for the basis for cultivation and management. But the illumination transmittance light is low.

Key words: Prefabricated solar greenhouse, Double film and double insulation structure cover structure, Temperature, Illumination, Humidity