The beneficial results of natural light greenhouse on temperature in the heartland of Takelamagan Desert

Air temperature in the greenhouse without heating in heartland of the Takelamagan Desert is more than 14℃ higher than outdoor air temperature, and soil surface temperature is more than 15℃ higher. Then vegetable varieties with high cold resistance can normally grow in the greenhouse. In addition,reed straw screen can increase air temperature about 0.9℃ and small plastic tunnel can add another 3.9℃ temperature to the greenhouse. Therefore most vegetables can be cultivated in the greenhouse when small plastic tunnel and screen are used.When greenhouse is heated,the temperature difference between greenhouse and outdoor could reach 30℃,then the thermophilic vegetables such as tomato, cucumber and pepper can grow very well. Air temperature in the greenhouse can be raised by 3.5℃/h by direct sunshine,and temperature does't fall quickly under cloudy conditions. Ventilation can reduce the air temperature increasing by 0.33 to 2.44℃/h·m²,and increase the air temperature falling by 3.7℃/h·m².The distribution of temperature in the greenhouse is variable with both ends' temperature are higher than that in the central section, the north side higher than the south side. If the distance between two stoves is at 25m,the temperature in the greenhouse will be keeped in homogeneity.