Effects of thickened plastic film and its two-year reuse with no tillage on maize yield, water use efficiency, and plastic film recycling rate

Increasing maize yield and reducing residual film pollution ‌remain‌ important issues ‌that need‌ to be addressed for maize production in the ‌semi-arid‌ region of the Loess Plateau. A field experiment was conducted to ‌investigate‌ the effects of different plastic film thicknesses ‌and their two-year reuse under no-till‌ conditions on maize yield, water use efficiency (WUE), and film recovery rate in ‌central Gansu Province‌ from 2023 to 2024. The experimental design‌ included two factors: plastic film utilization methods (T1: new film; T2: ‌two-year reuse of plastic film with no till‌) and plastic film thickness (H1: 0.01 mm; H2: 0.015 mm; H3: 0.02 mm), with six treatments. The results showed that ‌compared with the two-year reuse of plastic film with no till, new plastic film under H1, H2, and H3 significantly increased the average soil temperature in the 0–25 cm layer during the seedling to jointing stages by 6.71%, 5.60%, and 5.77%, respectively. ‌From the jointing to maturity stages‌, no significant differences in the average soil temperature in the 0–25 cm layer were observed between the new film and the two-year reuse of plastic film with no till. ‌‌Both the new film and two-year reuse of plastic film with no-till treatments‌ showed no significant differences in ‌harvest biomass‌ or yield between H2 and H3. ‌Under the H1 thickness, the dry matter accumulation at maturity and the yield of new plastic film increased by 14.54% and 24.10%, respectively, compared to the two-year use of no-till plastic film mulch. ‌Thicker films (H2 and H3) significantly increased WUE by 26.78% and 29.71%, respectively, compared to H1‌. Under the new film‌, the net income or ratio of output to input‌ was not significantly different for H1, H2, and H3. ‌Under two-year reuse of plastic film with no till‌, H2 and H3 increased net income by 45.74% and 46.10%, respectively, and ‌elevated the ratio of output to input‌‌ by 11.11% and 9.63%, respectively, ‌compared to H1‌. ‌Although‌ two-year reuse of plastic film with no till significantly reduced the ‌film recovery rate compared to the new film, thicker films under two-year reuse with no till significantly improved the recovery rate compared to H1‌. These results indicate that under the new film, thicker films ‌did not‌ significantly increase yield or net income; ‌however, thicker films under two-year reuse with no till‌ ‌significantly enhanced yield and net income‌. Therefore, ‌considering the yield, WUE, film recovery, and economic benefits‌, a 0.015 mm plastic film combined with two-year reuse‌ of plastic film under no-till conditions is a suitable plastic film measure for arid agricultural areas in the Loess Plateau.