Biodegradable film: a sustainable alternative to polyethylene film for Loess Plateau maize production

The use of biodegradable film as an alternative to polyethylene film is still controversial. Thus, a split-plot field trial was performed with planting patterns [traditional planting (FNM), and ridge-furrow planting with polyethylene and biodegradable films mulching (RPM, RBM)] coupled with nitrogen application levels [0 kg ha^-1 (N0), 180 kg ha^-1 (N180)] to explore the substitution of RBM for RPM in maize production. Compared with FNM, RBM and RPM increased the soil moisture storage by 11.6% and 11.5%, respectively, and soil mineral N concentration by 23.0% and 16.0% (under N180), but they reduced evapotranspiration by 3.9-11.7% and 7.9-36.4%, NH₃ volatilization by 38.3% and 35.3%, and N₂O emissions by 69.4% and 82.3% (2019 season). Moreover, compared with FNM, RBM and RPM increased the leaf area index by 16.8% and 19.4%, and aboveground dry matter by 10.8% and 16.5%, respectively. However, both mulching and N fertilization reduced the soil organic matter after 3 years of production. Path analysis revealed the differences in the influencing pathways of yield and the utilization of water and nitrogen. Consequently, compared with FNM, RBM and RPM under N180 improved the maize yield by 6.2% and 8.4%, and water use efficiency by 17.3% and 44.4%, respectively, but regardless of fertilization, they increased N harvest index by 9.2% and 10.8% and N use efficiency (2019 season) by 6.5% and 4.0%. These results demonstrated that the biodegradable film mulching was a viable replacement for polyethylene film mulching in maize production on the Loess Plateau in terms of soil fertility, plant growth, yield, and utilization of water and nitrogen.