Evaluating energy flow and greenhouse gas emissions in rainfed wheat production

Excessive consumption of energy in Iran resulted greenhouse gas emissions and related risks to the environment and human health. The aim of this study was to evaluate the effects of tillage and cultivation of wheat (including conventional farming, reduced tillage and direct seeding) on energy consumption and environmental pollution in the Kalpoosh region of Semnan province. Data were collected through interviews in 30 typical fields of wheat production. Data were analyzed with regard to inputs consumption, inputs energy and greenhouse gas emissions from the consumed energy and tillage method. Total inputs energy from the consumed inputs varied between 13900 to 18713 MJ ha-1. Results indicated that in conventional method, fuel consumption had the most share of energy input (37.8 % of total) followed by Nitrogen (26.5%) and seed (17.4%), respectively. Nitrogen had the most share of energy input in reduced tillage (31.7%) and direct seeding (35.7%). Maximum and minimum of greenhouse gas emissions (CO2, CH4 and N2O) were related to conventional seeding (11713 kg equivalent CO2 ha-1) and direct seeding ( 2721 kg equivalent CO2 ha-1.), respectively. Wheat yield differences in three methods wasn’t significant, maximum and minimum of wheat yield related to reduced tillage, direct seeding, respectively. Maximum and minimum of productivity belonged to direct seeding (0.21) and conventional tillage (0.16), respectively. It can be concluded that using conservation tillage (tillage and direct seeding), without a significant decrease in the yield of wheat, reduced fuel consumption, energy and greenhouse gas emissions, and increased energy efficiency and economical productivity.