Evaluation Energy Flow and Analysis of Energy Economy for Irrigated Wheat Production in Different Geographical Regions of Iran

Introduction :

Agriculture is an energy conversion process. In this process, solar energy, fossil fuel, and electricity are converted mainly into food and fiber. In the agricultural section, the trend of energy consumption increases rapidly every year. Constraints on agricultural land, population growth, changes in infrastructure, and a trend towards high living standards have contributed to increase energy use in the agricultural sector. Fuel, electricity, machinery, seeds, chemical fertilizers, and chemical pesticides have a significant share in supplying energy sources. Effective use of energy in agriculture reduces environmental problems and prevents the destruction of natural resources and develops sustainable agriculture as an economic production system. Wheat is the most strategic crop in Iran that more than 50.39% of arable land belongs to wheat.  

The current study has been done with the objects of evaluation of inputs and crop yield, input and output energy, and energy indices for irrigated wheat for seven provinces such as Alborz, Isfahan, Ardebil, Khorasan-e Razavi, Khuzestan, Golestan, and Hamadan. For this purpose, the required information gathered via study of publications, face to face interview with experts and leading farmers, and questionnaire completion by the irrigated wheat farmers in different cities of each understudy province. Then, with the help of equivalent energy equations, input and output energy and energy indices were calculated. In this research, simple random sampling method was used.

According to the results, total input energies of Alborz, Isfahan, Ardebil, Khorasan-e Razavi, Khuzestan, Golestan, and Hamadan provinces were calculated with 45458.84, 92714.8, 38755.34, 104701, 50971.2, 26198, and 49362. 64 MJ ha-1 respectively, while the output energy for those provinces were 162169.28, 131958.8, 77381.39, 122297, 141901.2, 134106, and 125511.69 MJ ha-1, respectively. The maximum share of energy input for Alborz, Ardebil, Khuzestan, Golestan, and Hamadan provinces were regarding to chemical fertilizers with amounts of 43.06, 43.16, 58.33, 38.05, and 47.57 percent, respectively, while irrigation energy requirement had maximum share in Isfahan and Khorasan-e Razavi with 62.36 and 57.17 percent, respectively. The minimum share of energy input for Alborz, Isfahan, Ardebil, Khorasan-e Razavi, and Golestan provinces was calculated for labor energy requirement with 0.39, 0.29, 0.79, 0.18, and 0.26 percent, respectively, while in Khuzestan and Hamadan, chemicals consumed the lowest energy with 0.55 and 0.89 percent, respectively. Share of direct energies for all understudy provinces were 44.61, 72.13, 41.22, 67.48, 30.75, 39.44, and 39.91 percent, share of indirect energies were 55.39, 27.87, 58.78, 32.52, 69.25, 60.56, and 60.09 percent, share of renewable energies were 27.99, 65.91, 32.35, 60.57, 19.26, 34.92, and 35.16 percent, and share of nonrenewable energies were 72.01, 34.09, 67.65, 39.43, 80.74, 65.08, and 64.84 percent, respectively. Energy ratio for Alborz, Isfahan, Ardebil, Khorasan-e Razavi, Khuzestan, Golestan, and Hamadan provinces were 3.57, 1.42, 3.48, 1.17, 2.78, 5.12, and 2.54, respectively, and energy productivities were 0.26, 0.11, 0.26, 0.08, 0.21, 0.38, and 0.18 kg MJ-1, respectively. Average input energy, output energy, energy ratio, energy productivity, and net energy gain for all provinces were 58308.83 MJ ha-1, 136092.15 MJ ha-1, 2.87, 0.212 kg MJ-1 and 77783. 31 MJ ha-1, respectively. Total input energy cost for irrigated wheat production was 57.966 ×106 Rial ha-1. The Energy intensiveness, Energy intensiveness value, Energy intensity cost, and Energy ratio cost were found as 1.299 MJ (103 Rial)-1, 0.641 MJ (103 Rial)-1, 10853.05 Rial kg-1, and 1.21, respectively.

In order to reduce the share of indirect energy and non-renewable energy, organic fertilizers should be replaced by chemical fertilizers and plant residues in the field. Minimum tillage should also be used in land preparation operations to reduce fuel consumption, maintain organic matter and soil moisture and reduce soil erosion. To compensate for some of the elements taken from the soil by the plant and the increase of organic matter and fertility of the soil, it is recommended to return part of the plant residues to the soil. The use of combined machines that can perform several simultaneous operations and minimizing and protecting soil tillage to reduce fossil fuel consumption through minimum use of machinery should be investigated as a national necessity.