Effect of Wood, Sand, and Tire Chips Mulches on Evapotranspiration Using ZFP Model

One method of determining evapotranspiration is zero flux plane (ZFP). This method estimate the evapotranspiration based on water content and soil suction. This method can also estimate the value of evaporation, evapotranspiration and ground water recharge. The data used in this study were obtained from a field experiment at Isfahan University of Technology. The experiment was factorial design [3×8] in the basic design of randomized complete blocks that the first factor was the types of mulch and the second factor was the depth of soil mulch. The field trial was conducted for 44 days. Results obtained from the ZFP model was compared with Ref-ET and OPTIWAT models. The experiment consisted of wood, sand and tire chips mulches with 2.5 and 5 cm thickness in the plots. Three plots were planted with grass and three plots left uncovered. The results showed that the depth of ZFP varied in different mulches. The highest ZFP depth was related to the uncovered plot and the lowest ZFP depth was related to the plot with 5 cm sand thickness. the results indicated that the experiment plot with no mulch had the greatest evapotranspiration (178 mm) and then woody chips mulch with a thickness of 5 cm, tire chips mulch with a thickness of 5 cm, tire chips mulch with a thickness of 2.5 cm, sandy mulch with a thickness of 2.5 cm, the woody chips mulch with a thickness of 2.5 cm and sandy mulch with a thickness of 5 cm, had more evapotranspiration, respectively. the results showed that the amount of evapotranspiration obtained by the ZFP model with the results of the Ref-ET and OPTIWAT model, were different. Ref-ET and OPTIWAT models under-estimated the actual evapotranspiration obtained by ZFP. In Ref-ET model, the equation of modified Blany-Cridle had the closest estimation (159 mm) to the evapotranspiration determined by ZFP model. In OPTIWAT model, the modified Jensen-Haise method had the nearest estimation (161.4 mm) to the ZFP model.