Effect of residual plastic film on infiltration of one-dimensional soil columns under drip irrigation

ABSTRACT Plastic-film mulching plays an important role in farming practice and acts as a barrier to soil surface. Residual plastic film (RPF) affects the water and nutrient flow in the soil. A column experiment was conducted to observe the variation of water infiltration in the soil and wetting front under different amount and distribution of RPF. Eight kinds of RPF treatments (0, 40, 80, 160, 270, 400, 800 and 1400 kg hm−2) and two kinds of distribution treatments (average distribution and decreasing distribution layer by layer) were designed in the experiment. The results showed that RPFs had a negative impact on soil water infiltration and wetting front, especially if higher than 400 kg hm−2. The stable infiltration rate decreased 64.3% in average distribution and 71.4% in decreasing distribution layer by layer. The migration distance of the wetting front decreased by 2.51 cm in average distribution and 3.32 cm in decreasing distribution layer by layer. The Kostiakov and power function models suggest that decreasing the distribution layer by layer provides greater benefits to farming soil. This study provided a theoretical reference for actual soil water movement patterns in RPF-contaminated areas of the field.