通过探索适期揭膜技术对制种玉米生长及地膜残留的影响，为黑河灌区制种玉米产业可持续发展和降低制种玉米生产中地膜污染提供科学依据。于2022年开展提前揭膜大田试验，依据玉米生育期设置了拔节期、大喇叭口期、抽雄期、乳熟期及成熟期5个揭膜处理，研究了适期揭膜技术对制种玉米生长、土壤水热状况、经济效益以及地膜残留等的影响，2023年通过示范进一步验证适期揭膜技术的可行性。结果表明，与对照成熟期揭膜相比，2022年提前揭膜处理生育期延长2～5 d，制种玉米籽粒产量增产2.27%～6.60%，玉米秸秆产量增产2.24%～8.68%，利润提高了6.78%～12.16%，地膜捡拾率提高了5.5~23.7个百分点；2023年拔节期揭膜处理制种玉米籽粒产量增产3.27%，玉米秸秆产量增产3.17%，利润提高了7.67%，地膜捡拾率增加23.7个百分点，地膜残留量在连续揭膜3 a后下降39.2%。拔节期揭膜处理6 — 9月0～60 cm土层土壤含水量平均下降了0.55%～2.38%；4 — 9月0～15 cm土层土壤地温平均增加了-1.15～0.31 ℃。综合各项指标得出，黑河灌区制种玉米最佳揭膜时期为拔节期(7～9片展开叶)，此时揭膜不会造成玉米减产，同时实现地膜降残留、减污染，是适宜黑河灌区减轻制种田地膜污染的新型技术，有利于玉米制种产业的绿色发展。

To explore the effects of timely film removal on seed maize growth and plastic film residue, and to provide scientific evidence for sustainable development of the seed maize industry and pollution reduction in the Heihe irrigation district, a field experiment of early film removal was conducted in 2022. 5 removal stages were set according to maize growth stages: jointing stage, large trumpet stage, tasseling stage, milking stage, and harvest stage. Effects of timely film removal on seed maize growth, soil hydrothermal condition, economic benefit, and plastic film residue were studied, and its feasibility was further verified by demonstration in 2023. Results showed that, compared with film removal at harvest (control), early removal in 2022 prolonged the growth period by 2 to 5 days, increased seed maize grain yield by 2.27% to 6.60%, increased stalk yield by 2.24% to 8.68%, raised profit by 6.78% to 12.16%, and improved film recovery rate by 5.5 to 23.7 percentage points. In 2023, film removal at jointing stage increased seed maize grain yield by 3.27%, stalk yield by 3.17%, profit by 7.67%, film recovery rate by 23.7 percentage points, and reduced film residue by 39.2% after three consecutive years of removal. For jointing-stage removal, soil moisture in the 0 to 60 cm layer decreased by 0.55% to 2.38% from June to September, while soil temperature in the 0 to 15 cm layer increased by -1.15 to 0.31 ℃ from April to September. Based on comprehensive indicators, the optimal film removal stage for seed maize in the Heihe irrigation district was the jointing stage(7 to 9 expanded leaves). Removal at this stage did not cause yield reduction, while reducing plastic film residue and pollution, making it a suitable new technology for alleviating plastic pollution in seed fields and promoting green development of the seed maize industry.

S513

甘肃省农业生态环境保护专项新技术研发推广项目(HT-SHGK-2024-037-包2)；甘肃省科技厅重点研发项目(24YFNA008)；甘肃省农业农村厅科技支撑计划项目(KJZC-2024-14)；张掖市市级科技计划(B类)专项项目(ZY2024BJ53)；甘肃省科技厅科技型中小企业技术创新基金项目(23CXGG0010)。