Effects of drip irrigation regimes on tomato fruit yield and water use efficiency

A well-designed drip irrigation system with appropriate intervals and water amount loses almost no water to runoff, deep percolation and evaporation. In the present study, potted tomato plants were watered by different regimes of drip irrigation and the effects of tomato vegetative growth, fruit yield and irrigation water use efficiency were examined in order to find an appreciate drip irrigation regime for greenhouse tomato in Jiangsu Province, China. Experiment was designed as a factorial split plot with 3 levels (2, 3 and 4 day) of irrigation frequencies or intervals as the main plot and 3 levels (1.8, 1.5 and 1.2 dm) of water amounts. As confirmed by the growth curve analysis using a modified mathematic equation, the differences in plant vegetative growth among different drip irrigation regimes were small. The differences in fruit yield among irrigation water frequencies were significant (P≤0.05) and there was also a significant interaction (P≤0.05) between irrigation frequency and water amount. The highest fruit yield was recorded in the plot with irrigation interval of 3 days and irrigation water amount of 1.5 dm and the lowest fruit yield was recorded in the treatment of 4 day1.2 dm. This suggested that the fruit yield would be further lower if the irrigation interval was set longer and the irrigation water amount was set lower at the same time. In general, irrigation water use efficiency tended to increase with a decline of irrigation amount at the same irrigation interval, with the highest value recorded in the treatment of 3-day irrigation interval with 1.2 dm water amount. It was suggested that the 3-day irrigation interval and 1.5 dm water amount at each time were appropriate under the drip irrigation for greenhouse tomato in Jiangsu Province, China.