The effect of farm size on the sustainability of wheat production using emergy approach

The effect of three farm areas, including small, medium, and large, on the sustainability of wheat production was studied using the emergy technique in 2018–19 in Jovein, Iran. By increasing the size of the farm, the share of renewable natural resources decreased and the share of purchased resources increased. The total emergy supporting small, medium, and large farms, was 1.39 × 10¹⁶, 1.95 × 10¹⁶, and 2.16 × 10¹⁶ sej ha⁻¹ yr⁻¹, respectively. In small farms, the share of renewable natural inputs, non-renewable natural inputs, and purchased inputs of total input emergy were 55.6 × 10¹³, 63.01 × 10¹⁴, and 70.30 × 10¹⁴ sej ha⁻¹ yr⁻¹, respectively. However, the share of renewable natural inputs, non-renewable natural inputs, and purchased inputs on large farms were 50.9 × 10¹³, 11.38 × 10¹⁶, and 98.03 × 10¹⁵ sej ha⁻¹ yr⁻¹, respectively. As the farm size increased from small to large, the emergy yield ratio and emergy investment ratio increased by 11.11% and 101%, respectively, while the unit emergy value, renewable emergy ratio, emergy investment ratio, and environmental sustainability index decreased by 27.31, 50.61, 45.45, and 18.65%, respectively. According to the results, although cultivation in large farms uses less renewable environmental resources and more purchased resources, a higher yield is produced per unit area.