conservation tillage can reduce energy consumption and carbon emissions in the production of rainfed sunflower

abstract in order to assess the environmental impact of agricultural activity, the long-term sustainability should be considered. in order to achieve solutions to reduce energy consumption and carbon emissions in the production of rainfed sunflower, this assessment was conducted in the north east of iran. four production methods, i.e. conventional tillage (ct), tow reduced tillages (rt1and rt2) and direct seeding (nt) were evaluated. the highest energy consumption (12.3 gj.ha-1) and carbon emissions (248 kg c-eq ha-1 and 155 kg c-eq t-1) were related to the conventional method. the least energy input (9.12 gj ha-1) and carbon emission (183.3 kg c-eq ha-1 and 118.6 kg c-eq t-1), were related to nt method. the greatest amount of sustainability index (is) was related to nt method, followed by rt2 (1.96), rt1 (1.79) and ct (1.53). in farm operations, fuel and nitrogen fertilizer were the key factors relating to energy use and carbon emission. in comparison of production methods, the conservation tillage was significantly more efficient. in conservation tillage, input energy and fuel consumption per hectare were 30% and 90% lower than conventional method, respectively, but there was no reduction in yield and energy output. based on the lower power consumption and greater energy efficiency, conservation tillage methods (in particular, reduced tillage and no-tillage) was recommended to  replace the conventional tillage.