Study on the Diurnal Variation of Greenhouse Environment under Different Weather Conditions

[Objective] The aim was to provide basis for reasonably regulate the environmental factors and guide the production practices of crops in greenhouse.[Method] Through determining the temperatures and light intensities in and outside sunlight greenhouse under different weather conditions,the variation law of ground temperature in sunlight greenhouse under different weather conditions and the ground temperature change at different soil depths under the same weather condition were analyzed.[Result] In cloudy days,while it was sunny,the light intensities and air temperatures in and outside sunlight greenhouse were increased;while it was cloudy,the light intensities in and outside sunlight greenhouse were decreased and their temperatures were increased sowly or even decreased.In rainy days,both the light intensities in and outside sunlight greenhouse were very low,the average light intensities in and outside sunlight greenhouse in daytime were 60 and 150 lx resp.and their highest light intensities were 142 and 307 lx resp.In snowy days,the average light intensities in and outside sunlight greenhouse in daytime were higher than that in rainy days,being up to 150 and 200 lx.The largest decreasing range of indoor temperature was 5.40 ℃ and that of outside temperature was 10.46 ℃.The change range of ground temperature in sunlight greenhouse in clear days was largest.Under the same weather condition,the change ranges of ground temperature at different soil depths were: 5 cm10 cm 15 cm 20 cm.[Conclusion] The daily change of greenhouse environment mainly depended on pridian weather and insulation situation.