Evaluation of Schwartzman & Zur's Model in Order to Determine Emitter's Distance in Drip Irrigation

In trickle irrigation, dripper spacing consider on the basis of wetting pattern and wetted area. Then, wetting pattern dimension that is named wetting bulb, is effective parameter in dripper choice and in optimal design of trickle irrigation systems, it is necessary to determinate its amount exactly. In order to study possibility of use of Schwartzan & Zur model to determinate of dripper spacing in trickle irrigation, this research have done in a sandy soil in Albaji region, Khuzestan province, Iran.this model has no suitable efficiency in wetting patterns approximation in this study conditions. so on the basis of measured data, Schwartzman & Zur model was calibrated. With mean relative error of 7%, R2=0.944 and RMSE=5/7 for predicting of wetted diameter and mean relative error of 6/8%, R2=0.914 and RMSE=5 for predicting of wetted depth was successful. Finally, in order to determine dripper spacing in optimal designation and management of trickle irrigation systems and for increase of irrigation efficiency in this study region a table was offered.