Abstract: To find out the characteristics of temperature and light conditions in sinking solar greenhouse, authors measured the air temperature, temperature of inner surface of back wall and total solar radiation in a sinking solar greenhouse, and compared with a non sunken greenhouse. The results indicated that on sunny day, at 13：00 the air temperature and temperature of inner surface of back wall were highest, which were 35.53℃ and 41.80℃, respectively, air heating rate was 6.48℃/h, mean temperature difference inside and outside greenhouse was 17.47℃, difference between day temperature and night temperature (DIF) was 14.20℃ in sinking solar greenhouse. The same indices on cloudy day were 15.83℃ and 15.35℃ at 14：00, 1.27℃/h, 9.78℃, 2.47℃. The highest temperature of inner surface of back wall was 18.71℃ at 13：00, air cooling rate was 0.10℃/h, mean temperature difference inside and outside greenhouse was 5.67℃, DIF was -0.19℃ in sinking solar greenhouse on light snow day. The mean minimum temperature was 7.35℃ in sinking solar greenhouse in winter. On sunny day, the total solar radiation transmittance in sinking solar greenhouse was 25%-80%, the relation between total solar radiation inside and outside greenhouse was positive correlation, daily variation of total solar radiation inside greenhouse presented a parabolic trend, the space distribution of total solar radiation was more complex than that in nonsunken greenhouse, so it needs to take proper measures to improve lighting conditions and use the space reasonably in the greenhouse. The test results can provide basis for the run of sinking solar greenhouse and guidance of crop production in greenhouse.

Key words: Sinking solar greenhouse, Air temperature, Temperature of inner surface of back wall, Total solar radiation, Radiation transmittance