Effects of biodegradable film types and drip irrigation amounts on maize growth and field carbon sequestration in arid northwest China

Biodegradable film (BF), as a superior substitute for traditional polyethylene film (PF), has experienced a consistent increase in China. However, a significant research gap persists regarding the utilization of BF in assessing farmland carbon balance. This experiment examined the responses of maize growth, yield, irrigation water productivity (IWP), CO2 emissions, and field net carbon sequestration (NCS) to two BF types (BF1, 100-day induction period, and BF2, 80-day induction period), and PF, and three irrigation amounts (I1, I2, I3: 5250, 5625, and 6000 m3 ha–1), by conducting a two-year (2019–2020) field trial in a typical arid and semi-arid region of China. The results indicated that biodegradable film mulching (BFM) negatively affected maize growth, resulting in reduced yield and IWP. Especially under the I1 irrigation level, the biodegradable film reduced maize yield by 6.26%–13.99% and IWP by 6.64–13.85%. Notably, in the I2 irrigation level, BF1 mulching had a comparable impact on maize yield and IWP to that of PF. Additionally, the increase in irrigation amounts exerted a more pronounced promoting effect on maize total biomass than on yield and IWP. Concerning carbon balance, short-term BF application resulted in reduced CO2 emissions (5.74–6.30% under BF1 and 9.27–12.37% under BF2), without any significant impact on NCS in cropland. Taking into account the economic value of maize and farmland ecology, we recommended utilizing irrigation amounts of 5625 m3 ha–1 for BF application in arid areas, while opting for a BF with a longer induction period whenever feasible.