Analyze of Microclimate Characteristics of Plastic Greenhouse in Winter in Southern Area of Guangxi

The microclimate characteristics of plastic greenhouse in the winter in southern area of Guangxi is studied. Mi- croclimate condition in the winter was observed in the plastic greenhouse. The microclimate characteristics in the inside and outside of the plastic greenhouse were analyzed. The results showed that transmittance was 70%-80% in the awning, and was high in the overcast days, low in the sunshine days. The daily average temperature increased 1.3-1.9℃ equally in the awning, The highest temperature increased 3.9-8.4℃, The lowest temperature increased 0.8-1.3℃, The diurnal range inside was 2.7-7.1℃ higher than outside, The temperature reversal is 0.2-0.9℃ inside the plastic greenhouse in the fair days and the cloudy days night. In awning 0, 5, 10, 15, 20 cm various soil layers ground temperature average warming 2.8-3.6℃. The surface maximum temperature in the cloudless days and in the greenhouse was 0.1-3.6℃ higher than out- side, while the lowest temperature was 2.2-5.2℃. The diurnal range inside was -5.1-2.2℃ higher than outside. There was temperature reversal at 12:00 p.m. Inside the plastic greenhouse in the fair days. The average relative humidity inside was higher than outside 10%-23%. The research provided the scientific basis for the instruction agricultural production and the big awning management in winter.