Evaporation increased especially during the first weeks after transplanting where plants did not have enough canopies to shade the soil. Plastic mulches directly affect the microclimate around the plant by modifying the radiation budget (absorptivity vs. reflectivity) of the surface and decreasing the soil water loss. These results are also in agreement with those of Jenni et al. (2000), Orzolek (2000), Orzolek et al. (2003), El-Nemr (2006) and Korir et al. (2006). Table 5 shows the climatic data as average during both of experimental seasons. It also shows potential evaporation rates from class A pan which sets near field and reference crop evapotranspiration (ET0) values were calculated based on FAO Penman–Monteith method.