Distribution characteristics of residual film over a cotton field under long-term film mulching and drip irrigation in an oasis agroecosystem

Abstract

We examined the distribution characteristics of RPF in the topsoils (0–40 cm) in an oasis agroecosystem in Northwest China. After cotton harvest in 2016, we collected 2304 soil samples - A total of 2471 pieces of RPF were separated and weighted. The accumulation of the larger RPF fragments (>25 mg per piece) primarily took place from 5 to 15 years after mulching started. It took over 15 years for the larger RPF fragments to degrade into smaller ones (<25 mg per piece), which accounted for 65% of the total number of RPF fragments in the field with 19-year of mulching. That said, with the constant mulching management, RPF pieces became more fragmented and distributed deeper, making mulch film recovery more challenging. To the best of our knowledge, this is the first time that the dynamics of RPF distribution in the soil profile after long-term mulching have been characterized. If the current mulching method continues, the accumulated RPF is going to cause severe soil pollution and risk the sustainability of the oasis agroecosystem.