Determination of ponding time and number of on-off cycles for sprinkler irrigation applications

The objectives of this study were to develop an equation for the ponding time, tp, and determine the number of on-off cycles using the infiltration equations introduced by Horton and Kostiakov and to compare the observed and predicted ponding times tp. To achieve these objectives, a sprinkler infiltration test was conducted on the Harran soil series at the Sanhurfa-Koruklu, Tubitak Agricultural Research and Development Station on the Harran plain. The soil characteristic parameters of the Horton and Kostiakov equations were determined from the results of sprinkler infiltration tests. The ponding time equations were developed by choosing a sprinkler application rate of is = 13.61 mm h−1 that is higher than the steady-state infiltrability rate of iss = 7.1 mm h−1. The number of on-off cycles was then determined from repeated cycles. The ponding times tp for the experiment, the Horton equation, and the Kostiakov equation were 4.17, 4.09 and 2.69 h, respectively. The numbers of on-off cycles for all three methods were estimated to be two. Under the same management conditions, it was concluded that irrigation at a rate is > iss could be completed in 44% less time without the occurrence of runoff and erosion.