Effect of various types of plastic films on the soil and air temperatures in 80-cm high tunnels

Abstract

Studies on the effects of various types of plastic films on the soil and air temperatures in 80-cm high tunnels indicated that a polyvinyl-chloride (PVC) film retained more heat during the night than a clear polyethylene (PE) film, while the maximum daily temperatures were not as extreme. Daily temperature variations were less under PVC than under clear-PE film. Soil temperatures in plastic tunnels were similar with or without black-PE mulch, but air temperatures were raised by black-PE mulch under the tunnel. An unusually late snow-fall of 33.5 cm that occurred on 5 April 1982 did not damage the plastic tunnels. Soil temperatures outside the tunnels under the cover of snow remained at 0°C, while those under the tunnels reached 27°C during the day. The maximum air temperature above the snow cover was only 4.5°C; the maximum inside the plastic tunnels was about 24°C.