Abstract:  In order to study the effects of three-year mulching with different thickness of plastic film on soil water and heat effects, maize yield and film residue, field experiments were conducted with three-year mulching of plastic film. In the field experiment, four thickness levels of the mulch (0.008, 0.010, 0.012, 0.015 mm) were randomly designed. The results showed that: ① The mulch film with thickness of 0.012 mm and 0.015 mm had good effect of increasing temperature and preserving the moisture of the soil after many years. Compared with one-year mulching CK, water consumption during the growth period of film mulching with thickness of 0.012 and 0.015 mm only increased by 1.96% and 1.14%, and the soil temperature from corn sowing to jointing stage only decreased by 0.74 and 0.71 ℃. ② Under three-year mulching, the growth of crops was affected, and the yield and water use efficiency of maize reduced. Yield and water use efficiency under 0.008 mm thickness mulch were significantly lower than that of CK, 13.24% and 18.12%, but the efficiency under the thickness of 0.010, 0.012 and 0.015 mm was close to that of CK, and only decreased by 2.27%~4.09%, 2.85%~8.36%. ③ Under three-year mulching, the input cost effectively reduced, and the ratio of output to input of maize significantly increased by 13.73%, 25.00%, 26.47% and 25.49% compared with CK. ④ Three-year mulching significantly reduced the film residues, which was 55.74%~61.42% lower than CK, but the film with thickness of 0.008 and 0.010 mm was fragile and difficult to recover, making the residual coefficient of plastic film as high as 35.60% and 32.97%. When the film thickness increased to 0.012 and 0.015 mm, the residual coefficient decreased to 21.99% and 19.81%. In conclusion, the application of plastic film with thickness greater than 0.012 mm in multi-year mulching could ensure maize yield, improve water use efficiency and the ratio of output to input, and effectively reduce residual film pollution.

Key words: film thickness, three-year mulching, water use efficiency, ratio of output to input, film residues, maize

摘要： 为探讨不同厚度地膜一膜三年覆盖对土壤水热效应、玉米产量及地膜残留的影响，分别设置厚度为0.008、0.010、0.012、0.015 mm的地膜一膜三年覆盖大田试验。结果表明:①厚度0.012、0.015 mm地膜覆盖三年仍有较好的增温保墒效果，生育期耗水量仅比一年一覆膜（CK）增加1.96%、1.14%，玉米播种至拔节期土壤温度分别降低0.74、0.71 ℃。②一膜三年覆盖不同程度影响了作物生长发育,降低了玉米产量及水分利用效率。0.008 mm地膜处理的产量、水分利用效率显著低于CK 13.24%、18.12%；但0.010、0.012、0.015 mm处理与CK相近，产量和水分利用效率的降幅分别为2.27%～4.09%、2.85%～8.36%。③一膜三年覆盖有效降低了投入成本，玉米产投比比CK分别显著提高13.73%、25.00%、26.47%、25.49%。④一膜三年覆盖显著降低了地膜残留量，比CK降低55.74%～61.42%；但厚度为0.008、0.010 mm地膜使用后易破碎、不易回收，使地膜残留系数分别高达35.60%、32.97%；地膜厚度为0.012、0.015 mm时，地膜残留系数可分别降低到21.99%、19.81%。研究认为，一膜三年覆盖中采用厚度大于0.012 mm地膜，可保证玉米产量，提高水资源利用效率及产投比，有效降低残膜污染。

关键词: 地膜厚度, 一膜三年覆盖, 水分利用效率, 产投比, 地膜残留, 玉米