Analysis of several discharge rate–spacing–duration combinations in drip irrigation system

In order to study the use of water irrigation in a rational way, several combinations of discharge rate, irrigation duration and inter-emitter distances were tested. For instance, three dripper spacings of 30, 50 and 70 cm which delivered water volumes of 4, 8 and 16 l per dripper, respectively, and three discharge rates of 2, 4 and 8 l/h for each spacing, were applied. An overlapping of the wetted bulbs was observed at the end of the different irrigation experiments. The inter-dripper root-zone had an average water content of 45% and a coefficient of uniformity of 90%. The discharge rate of 2 l/h applied to a 70 cm dripper spacing was characterised by water losses of 15% due to the significant irrigation duration (8 h). From this study, we reach the following conclusions, specific to the soil type and practical culture. 1. The maximum irrigation duration does not exceed 4 h. 2. Two hours durations can be used for the different spacings, each of which was characterised by its own discharge rate.