Environmental impacts of energy use in wheat tillage systems: A comparative life cycle assessment (LCA) study in Iran

The agricultural sector is facing increasing societal expectations to contribute to the global reduction of impacts on the environment. This study aims to evaluate energy use and environmental impacts of different winter wheat tillage systems in the central Fars province, Southwest Iran. To meet the objectives, different energy indices and environmental impact categories were assessed for five wheat tillage systems; two conventional tillage systems: CT1 and CT2, and three conservation tillage systems: CMT (moldboard plough and combined seeder), RDT (reduced tillage) and NT (no-tillage). Total average energy consumption was estimated at 30,000 MJ/ha caused mainly by fertilizers, diesel fuel, water and seed inputs. The highest output-input energy ratio and energy productivity were observed in the conservation tillage systems RDT followed by NT and CMT. The LCA analysis confirmed that system RDT is the wheat tillage system in the region with the lowest impacts on the environment, the lowest energy input and the highest benefit to cost ratio compared to all other considered systems.