Abstract: Three treatments including dripping irrigation under plastic film mulching (DIUPM),furrow irrigation under plastic film mulching (FIUPM) and furrow irrigation without plastic film mulching (FIWPM) were designed in order to study the influence of irrigation patterns on environmental factors inside wide-span plastic film covered tunnel greenhouse. The relative humidity (RH),dew duration,soil water content,air and soil temperature were observed. The results indicated that the RH in the treatments of DIUPM and FIUPM were decreased compared to the FIWPM treatment. The dehumidified effectiveness in the DIUPM treatment was better than that in the FIUPM treatment. The dehumidified effectiveness varied at different times and different weather conditions. It was better during day times than at nights and btter in the sunny days than in the cloudy days. The dew duration decreased,the soil temperature in air and in 10cm soil depth enhanced,and the soil water content increased by the treatments of DIUPM and FIUPM.

Key words: Irrigation pattern, Irrigation pattern, Wide-span plastic film covered tunnel greenhouse, Air relative humidity, Soil temperature, Minimum air temperature