Ecological footprints of environmental resources for agricultural production in Iran: a model-based study.

A modeling system was used to calculate the resource footprints (land, water, nutrients, energy, fuel, electricity, and carbon) on a large scale in agricultural production systems (Iran as a case study), and this report is an introduction of this modeling system for future studies. Under irrigated conditions, the highest land footprint was observed in pulses and oil grains (0.6 ha t-1). The lowest water footprints were found in silage corn (300 m3 t-1), and the highest water footprints were observed in oil grains (4525 m3 t-1). The highest footprints of nitrogen were observed in maize (31.7 kg t-1), wheat (30.9 kg t-1), and oil grains (30.4 kg t-1), and the lowest value belonged to production of sugar crops (2.6 kg t-1). Most of the energy, fuel, electricity, and greenhouse gas (GHG) emissions were occurred under irrigated cropping systems compared with the rainfed systems. Under irrigated conditions, the highest footprints of energy, fuel, and electricity and GHG emissions occurred in the production of oil grains, and their values were 24397 MJ t-1, 161 L t-1, 1195 kWh t-1, and 1699 kg CO2eq. t-1, respectively. In general, wheat production in Iran has the highest cost in terms of resource use (water, elements, energy, and carbon) compared with the other plant products. Livestock and poultry products (especially red meat) also had the highest ecological footprint among the products.