Abstract:The residual plastic film seriously affected the soil water infiltration and evaporation. Five residual plastic film treatments were conducted to study the effects of different residual plastic film amounts (0kg/hm2,50kg/hm2, 100kg/hm2, 200kg/hm2 and 400kg/hm2) on soil water infiltration and evaporation characteristics, and the infiltration front, infiltration rate, cumulative infiltration, cumulative evaporation and the evaporation rate were mainly studied based on the different residual plastic film quantities for sandy loam and sandy soil, and then the performance of main soil infiltration and evaporation model with residual plastic film was evaluated. The results showed that with the increase of residual plastic film quantity in the soil, the infiltration rates of sandy loam and sandy soil were decreased slowly, the time required for wetting front migration was increased significantly, and the sandy loam with 400kg/hm2 residual plastic film treatment (SL5) was increased by 27.56% compared with that of nonresidual plastic film treatment (SL1) at 30cm soil layer. In addition, the cumulative infiltration amount was significantly decreased (P<0.05) in the same infiltration time, and the cumulative infiltration amount of SL5 treatment was reduced by 52.01mL (23.12%) compared with SL1 at the end of infiltration. The evaporation rate and cumulative evaporation were significantly reduced (P<0.05) with the increase of residual plastic film quantity, the cumulative evaporation rate of SL5 treatment was 30.63% less than that of SL1 after evaporation, and the influence of different residual plastic film amounts on sandy loam was greater than that of sandy soil. The four major soil water infiltration and evaporation model were evaluated, it was showed that both Kostiakov and Philip infiltration models can well simulate the soil water infiltration for the soil with residual plastic film, but the Philip model had better performance than Kostiakov model, and had better adaptability for sandy soil with plastic film residue. The fitting accuracy of Black evaporation model was decreased with the increase of residual plastic film quantity, but the Rose evaporation model was less influenced by the amount of residual plastic film. So it can be concluded that the Rose evaporation model was more suitable for the plastic film residual soil cumulative evaporation estimation.
