Application of subsurface drip irrigation with PVC tube to tomatoes in greenhouse

In view of the demand of efficient irrigation in greenhouse, a new subsurface drip irrigation with PVC tube was developed. Experiments of irrigation without plants and with tomato cultivation were carried out, and the irrigation capability and effect of subsurface drip irrigation with PVC tube were studied. The outer diameter of PVC tube was 20.4 mm, the inner one was 17.9 mm, 0.1 kg/m. Holes of irrigation were drilled on the wall of PVC tube, the diameter of which was 1 mm, and four holes became a group. Holes of irrigation were arranged along the PVC tube extended direction. The distance between central pots of two holes within a group was 20 mm, and the distance of central pots between groups was 300 mm. This drip irrigation system was designed specially for greenhouse irrigation, and the length of PVC tube was 6 m, the same as the length of greenhouse ridge. The tube was embedded below 30 cm of the soil surface, and there was a layer of filtration on the holes of irrigation. The results show that the uniformity of irrigation with PVC tube can meet the designed standard, using 15 kPa as irrigation pressure and 30 kPa soil water suction as the lower limit of irrigation. Compared with the common drip irrigation, subsurface drip irrigation with PVC tube is simple to be embedded, rapid to irrigate and evident to increase yield and water saving.