Carbon footprint and yield performance assessment under plastic film mulching for winter wheat production

As the demand for cereals increases with the growth of the global population, wheat (Triticum aestivum L.) yield needs to be improved, and the environmental impacts of wheat production need to be lessened. Plastic film mulching (PFM) is becoming recognized as a strategy that guarantees the sustainability of water resources and food production. To date, insufficient attention has been paid to examining the carbon (C) footprint of the PFM practice. A six-year field experiment was conducted to identify the effects of PFM with supplementary irrigation and nitrogen (N) fertilizer application on grain yield, greenhouse gas (GHG) emissions and the C footprint of winter wheat production. In comparison with conventional flat planting without mulch (CFP), the PFM strategy increased grain yield by 31.7% (P < 0.001) and water use efficiency (WUE) by 30.7%, mainly due to the improved soil hydrothermal conditions. Supplementary irrigation (I) under PFM (PFM+I) further enhanced grain yield (by 26.6%) but reduced WUE (by 37.3%) compared to PFM. PFM+I decreased the C footprint by 21.2% at the higher N application rate but increased the C footprint (27.2%) at the lower N application rate compared with CFP. The findings suggest that additional irrigation and higher N application rates should be avoided under CFP because of the resultant lower grain yield and increased environmental impacts. Conversely, under PFM, an increased N rate (higher than 75 kg had 1) and irrigation (if drought occurs) are recommended due to the higher grain yield and decreased C footprint. Nitrogen fertilizer application was the largest source of GHG emissions (56.5%), and increasing the N rate increased the C footprint of the cropping systems (P < 0.001). This suggests that an optimal N application rate could substantially mitigate GHG emissions and reduce the C footprint. Taken together, the combination of PFM with an appropriate N rate and irrigation regime in winter wheat is an effective management practice when considering both agronomic and environmental benefits. However, environmental concerns about white pollution should also be considered to ensure cleaner agricultural production when implementing PFM. Crown Copyright (C) 2020 Published by Elsevier Ltd. All rights reserved.