Toward Environmentally Sustainable Wheat Harvesting Operation in Rainfed and Irrigated Systems

This study aimed to assess the environmental sustainability of wheat harvesting operation in rainfed and irrigated farming systems in three different locations in Iran, including Sari, Mashhad and Parsabad Moghan counties. Four sustainability indices of energy, emergy, exergy, and greenhouse gas emissions were investigated in this research. Results revealed that the energy efficiency of harvesting operation in irrigated systems was higher than that in rainfed systems. The emergy analysis results highlighted that the environmental sustainability indices for rainfed systems in Mashhad, Parsabad Moghan, and Sari were 0.047, 0.035 and 0.034, respectively. The values for the irrigated systems were 0.036, 0.035 and 0.034, respectively. The results of exergy analysis also indicated that the exergy efficiency of harvesting operation in rainfed and irrigated systems in Sari and Parsabad Moghan was higher than that in other areas by 56.07 and 128.72, respectively. Total GHG emissions of harvesting operation in Sari, Parsabad Moghan, and Mashhad in rainfed systems were determined to be lower than that in the irrigated systems (54.88, 47.64 and 36.03 kg CO2eq ha-1 versus 67.52, 66.56 and 59.22 kg CO2eq ha-1, respectively). In conclusion, the wheat harvesting system was environmentally more sustainable in Sari and Parsabad Moghan counties in rainfed and irrigated farming systems, respectively.