Determination of emergy and greenhouse gas as indexes for agro-ecosystems sustainability assessment in production

Concerns about the growing trend of population and limited resources resulted in valuing sustainability and enhancing production. Discussion about new developments, environment, and productions cannot be complete without the sustainability model. Emergy analysis is one of the main tools to measure the sustainability of ecosystems by analyzing inputs, services, and energies with a nature-oriented approach. Accordingly, the present study strived for assessing ecological sustainability from emergy, greenhouse gas (GHG) emissions, and economic viewpoints in rice and wheat production in the province of Mazandaran, Iran. It was concluded that fuel contributes more to GHG emissions with shares equal to 53.89% and 50.6% in the production of rice and wheat, respectively. The average total GHG emissions in rice and wheat production in the region were also 1493.8 kgCO 2 eq/ha and 837.3 kgCO 2 eq/ha, respectively. Besides, the average total energy supporting rice and wheat production was estimated at 5.36E + 16 and 5.95E + 16 seJ/ha, respectively. The average modified environmental loading index for wheat and rice was 9.75 and 32.9, respectively. These values were larger than the results reported in the relevant studies, which reflect that there is heavy pressure on the environment due to such agricultural practices. The average environmental sustainability index was also 0.11 and 0.05 for rice and wheat, respectively. The smaller environmental sustainability index as compared to similar studies reflected the lower sustainability of these systems. Economic analyses revealed that the average total net returns of rice and wheat production were 16,980.51 and 1151.34 US$/ha, respectively. Therefore, rice production is more sustainable than wheat production. It is recommended to produce rice and wheat with more caution in this region, especially concerning chemical-based fertilizers and fuel consumption.