Agricultural plastic film residual (PFR) increase quickly with the development of mulching cultivation

and have a strong impact on soil water movement. In order to study the influence of PFR on water flow movement mechanism

the experiment was carried out in water saving experiment station of Jiuzhuang

Hetao irrigation area. There were six treatments

including three PFR amounts(0

300

600 kg/hm2) and two water infiltration amounts (20

80 mm). The influence of different PFR amounts on soil physical properties was studied

the effects of different PFR amounts and different infiltration amounts on soil water flow was analyzed based on dye tracing method

and the preferential flow characteristics for each treatments were evaluated. The results showed that soil bulk density

saturated water conductivity

and initial soil moisture content showed a decreasing trend with the increase of PFR amount

while an increasing trend for soil porosity. The random distribution of residual film in soil lead to higher variation coefficient of each physical parameter of PFR treatment. The development degree of soil preferential flow increased with the increase of PFR amount and infiltration amount. The maximum dyeing depth (MDSD) and the coefficient of variation of soil staining profile (Cv) of 300

600 kg/hm2 PFR treatment increased with the increase of PFR amount.Compared with 20 mm infiltration

the MDSD and Cv for PFR treatment at 80 mm infiltration increased by 47.23% and 27.34%

respectively. In addition

the characteristic index of preferential flow of different treatments was significantly different. Five characteristic preferential flow indexes (dyeing area

uniform flow depth

preferential flow ratio

length index

and coefficient of variation) revealed that the preferential flow of 300

600 kg/hm2 PFR treatment was higher than that of 0 kg/hm2 treatment. It can be seen that the increase of residual film amount and infiltration amount will increase the occurrence probability and strength of soil preferential flow.