Analysis of energy and greenhouse gas balance as indexes for environmental assessment of wheat and maize farming: a case study | Analiza energetske bilance in bilance toplogrednih plinov kot ocena okoljskih kazalnikov pridelave pšenice in koruze na primeru dveh kmetij

English. In this study, the net balance of greenhouse gas (GHG) emission and energy of wheat and maize production systems in two farms in Khuzestan province of Iran was assessed. The results showed that totally wheat farming is more efficient than maize farming in terms of energy and CO2-eq indexes. The total energy requirement for maize and wheat farming was 92560.24 MJ ha-1 and 39624.15 MJ ha-1, which caused the emission of 20191.47 and 7541.04 kg CO2-equivalent per hectare in maize and wheat farms respectively. Electricity, fertilizers and fuel were the most important pollutants of environment in terms of energy and gas emission in both farms. Theses inputs consumed 55.52, 22.62 and 6.44 % of total energy of maize and 47.32, 21.19 and 9.01 % of total energy of wheat farm and were responsible for the 88.60, 8.79 and 2.03 % of CO2-equivalent in maize and 86.54, 9.54 and 3.24 % of CO2-equivalent in wheat farms respectively. The results of this study also showed that the enhancement of 60.74 and 27.02 % in energy ratio and 46.06 and 27.87 % in CO2-eq index in maize and wheat farming can be expected using simple improving scenarios.

Slovenian. V raziskavi sta bili ocenjeni letna energetska bilanca in bilanca toplogrednih plinov pri pridelavi pšenice in koruze na dveh kmetijah, v provinci Khuzestan, Iran. Rezultati so pokazali, da je pridelovanje pšenice učinkovitejše kot pridelovanje koruze glede na energetsko bilanco in bilanco CO2. Celokupna poraba energije je za pridelavo koruze in pšenice znašala 92560,24 MJ ha-1 in 39624,15 MJ ha-1, kar je povzročilo emisijo 20191,47 in 7541,04 kg CO2 ha-1 pri koruzi, oziroma pšenici. Elektrika, gnojila in goriva so bili najvažnejši povzročitelji onesnaževanja okolja in emisije toplogrednih plinov na obeh kmetijah. Ti vložki so porabili 55,52; 22,62 MJ ha-1, kar je 6,44 % celokupne energije koruze in 47,32; 21,19 MJ ha-1, kar je 9,01 % celokupne energije energije pšenice. Pridelavi sta bili odgovorni za emisiji 88,60; 8,79 kg CO2 ha-1, kar znaša 2,03 % ekvivalenta CO2 pri koruzi in 86,54; 9,54 kg CO2 ha-1 in 3,24 % ekvivalenta CO2 pri pšenici. Rezultati te študije so tudi pokazali izboljšanje ob uporabi izboljšanega scenarija na 60,74 and 27,02 % v energetski bilanci in 46,06 in 27,87 % v bilanci CO2 pri koruzi in pšenici.