Contribution to the optimization of the drip irrigation duration

With the aim of rationalizing the use of water, several combinations betwee n discharge rate, time of irrigation and distance between emitters are gene rally used. Two drippers each discharging 4 l/h were used to produce a total volume of 36 liters during four and half hours. Three dripper distances namely 30, 50 and 70 cm were tested. The distribution of water and its uniformity were t he two parameters used to evaluate different irrigations. The analysis of the inter-dripper root-zones has shown that it is not neces sary to apply an amount of 18 liters per dripper in one irrigation for the two inter-dripper distances 30 and 50 cm. A study considering three criteri a such as bulb overlapping, uniformity coefficient and moisture average, sh owed that a time of one, two and four hours may be adopted as optimal irrig ation time for the three dripper distances 30, 50 and 70 cm respectively. I n term of those irrigation times, the inter-dripper root-zone will be submi tted to an average of volumetric water content equal to 45% and to a unifor mity coefficient equal to 90%. The irrigation times thus obtained, allow to reduce greatly the amount of w ater given to the crop at only one irrigation, and to avoid an important lo ss of water. They can also increase the number of irrigation application.