The quantities of residual plastic film in soil will further increase with the wide application of agricultural plastic mulching film, and the residual plastic film in soil will not only influence soil water movement, but also lower the infiltration properties. In the study, the experiments with six treatments and Three-time repetition were carried out in Huhhot, China, which included three kinds of cumulative quantities of residual plastic film (0, 5, 20 kg/hm-2), and two kinds of dripper discharges (0.5 and 2 L/h). The effects of different cumulative quantities of residual film and different dripper discharge on the drip wetting front and wetting patterns were studied by experiments and mathematical analysis, and the uncertain infiltration model was proposed on the basis of Kostiakov infiltration model, and the uncertainties of infiltration rate for different cumulative quantities of residual film treatments were quantitatively analyzed and compared using Bayesian analysis. The results showed that migration distances of drip wetting front decreased significantly with the increase of residual film for all treatments in the same period of time, especially that the effect of residual film on migration distance of drip wetting front in vertical direction were more significantly different (p<0.01) for high dripper discharge in the phase of soil water redistribution. When cumulative quantities of residual plastic film increased in soil, the drip infiltration rate would significantly slow down, which caused that the drip wetting patterns were smaller, and the drip wetting patterns of vertical direction under residual plastic film treatments were 10%-20%lower than that under the non-film treatment. In the meantime, cumulative quantities of residual plastic film had irregularly changed for the wetting patterns in the residual film region between 10 and 20 cm soil layer, and the more cumulative quantities of residual plastic film, the more irregular variety for wetting patterns. As the residual film increased, the posterior parameters standard error of uncertain infiltration model based on Kostiakov model apparently increased, and 95%posterior distribution interval were also enlarged using Bayesian analysis, and the effect of infiltration uncertainties for high dripper discharge (2 L/h) were more significant, which explained the augment of cumulative quantities of residual plastic film and increased the uncertainties of infiltration rate because of randomness of residual film location and the uncertainties of mixing compactness between residual film and soil. In conclusion, agricultural plastic mulching film would increase uncertainties of drip infiltration.% 随着农用地膜的大规模使用土壤中残膜量也随之剧增,土壤中农膜残留阻碍了水分迁移,降低了水分入渗性能。本文通过室内滴灌入渗试验设置了3个残膜量处理,分别为0、50、200 kg/hm2,并设高、低2个滴头流量处理,研究了残膜对滴灌水分入渗的湿润锋、湿润体的影响,分析了残膜条件下滴灌入渗速率的不确定性的变化过程。结果显示：随着土壤中残膜量增加,在相同时间内滴灌湿润锋的运移距离明显变小,其中高滴头流量处理在垂直方向更明显；随着残膜量的增加滴灌湿润体明显变小,同时湿润体在10~20 cm残膜区出现明显的不规则分布；通过 Kostiakov 入渗模型结合贝叶斯概率系统分析显示,土壤中残膜量增加将导致入渗模型的后验参数的标准偏差变大,95%置信后验区间增大,特别是高滴头流量处理影响更明显,可见随着残膜量的增加滴灌入渗速率的不确定性随之增加。
展开▼
