Tomato root response to subsurface drip irrigation

Four depth treatments of subsurface drip irrigation pipes were designated as 1) at 20, 2) 30 and 3) 40 cm depths all with a drip-proof flumes underneath, and 4) at 30 cm without a drip-proof flume to investigate the responses of a tomato root system to different technical parameters of subsurface drip irrigation in a glass greenhouse, to evaluate tomato growth as affected by subsurface drip irrigation, and to develop an integrated subsurface drip irrigation method for optimal tomato yield and water use in a glass greenhouse. Tomato seedlings were planted above the subsurface drip irrigation pipe. Most of the tomato roots in treatment I were found in the top 0-20 cm soil depth with weak root activity but with yield and water use efficiency (WUE) significantly less (P = 0.05) than treatment 2; root activity and tomato yield were significantly higher (P = 0.05) with treatment 3 compared to treatment 1; and with treatment 2 the tomato roots and shoots grew harmoniously with root activity, nutrient uptake, tomato yield and WUE significantly higher (P = 0.05) or as high as the other treatments. These findings suggested that subsurface drip irrigation with pipes at 30 cm depth with a drip-proof flume placed underneath was best for tomato production in greenhouses. In addition, the irrigation interval should be about 7-8 days and the irrigation rate should be set to 225 m(3) ha(-1) per event.