Alternative planting patterns of film-mulching cotton for alleviating plastic residue pollution in Aksu oasis, southern Xinjiang

Plastic film mulching has been adopted for cotton production for nearly 30 years in Xinjiang, China, plastic residues accumulate in the soil at extremely high levels, which has resulted in severe negative influences on the soil environment and natural ecosystem. Hence, it is necessary to develop new cultivation patterns for future sustainable agricultural production. The present method of drip irrigation with film mulching (FMDI) pattern may be replaced by drip irrigation without mulching (WMDI) pattern. The paper aims to evaluate the cotton growth, yield, and economic profits under WMDI and FMDI based on field observation and simulation of the AquaCrop model. Cotton yield under WMDI was 26.21% lower than that under FMDI, and the increasing irrigation rate reduced the yield gap between FMDI and WMDI. The FMDI cultivation pattern also presented more interannual stability of cotton biomass and yield than the WMDI pattern, with the average coefficient of variation decreasing by 25.47% and 10.71%, respectively. The costs of plastic film and fertilizer application were reduced by 100% and 15.38%, respectively, when replacing FMDI with WMDI, but the inputs increased by 42.86% and 26.06%, respectively, in seed application and field management. The decrease in cotton yield, ranging from 4.53% to 16.23%, resulted in a remarkable decrease in the economic benefits of cotton production. The results suggest that, although several obstacles exist to large-area popularization and application of the WMDI pattern at present, the WMDI pattern is a viable method to maintain sustainable development of cotton production and reduce plastic debris pollution in Xinjiang oasis areas and similar regions.