Introduction: In Golestan province, due to decreased rainfall and the subsequent decline in groundwater levels, the cultivation of crops such as rice has faced serious challenges. The use of cultivation techniques with lower water consumption and agricultural inputs can be an appropriate solution to this problem. For this purpose, a comparison was made between traditional (conventional) systems and dry-farming (direct-seeded) systems.
Materials and methods: To investigate fuel consumption, energy use, and greenhouse gas emissions in paddy rice (wet cultivation) and dry-farming systems in Gorgan County, 30 farms were selected through sampling of production systems during the years 2019–2020. The required data were collected through face-to-face interviews with the producers of this crop and by taking notes of all agronomic operations. The energy inputs of fuel, human labor, machinery and implements, pesticides, chemical fertilizers, and seeds were calculated based on their respective coefficients. The output energy was also calculated based on the paddy rice yield. Furthermore, energy indices including energy use efficiency, specific energy productivity, and net energy yield were also calculated. In this study, to calculate the Global Warming Potential (GWP), the emissions of three greenhouse gases—carbon dioxide (CO₂), nitrous oxide (N₂O), and methane (CH₄)—resulting from energy consumption for the production of agricultural inputs and the execution of various agronomic operations were taken into consideration. Finally, all calculations were performed using Microsoft Excel spreadsheets.
Results: The results showed that the total energy consumption in traditional farms with electric wells was 15 percent lower than in traditional farms with diesel wells. On the other hand, in dry-farming farms, the use of sprinkler or drip irrigation systems did not show much difference. Direct energy consumption in traditional diesel farms was the highest, which was 34, 71, and 74 percent higher than in traditional electric farms, dry-farming farms with sprinkler systems, and dry-farming farms with drip systems, respectively. The energy consumption efficiency in traditional diesel farms, electric farms, dry-farming farms with sprinkler systems, and drip systems was 5.10, 6.35, 13.15, and 13.22, respectively. Energy efficiency was lowest in the traditional diesel system and highest in both dry farming systems, so that for every megajoule of energy consumed in the traditional diesel, electric and dry farming systems, 160, 200 and 390 grams of product were produced, respectively, which actually indicated higher energy efficiency in dry farming farms. Also, for every kilogram of product produced in the traditional diesel, electric, dry farming with sprinkler system and tip, 950, 800, 430 and 430 grams of carbon dioxide equivalent were emitted, respectively, which in fact, traditional systems had almost 2 times more carbon dioxide emissions than dry farming systems.
Conclusion: Based on the assessment of greenhouse gas emissions resulting from input consumption, it was concluded that in the traditional diesel system, fossil fuel consumption, and in the traditional electric system, dry-farming with sprinkler irrigation, and dry-farming with drip irrigation, electricity consumption caused the highest greenhouse gas emissions. The largest share of energy consumption for rice production is related to irrigation water and chemical fertilizer use. Proper irrigation scheduling and management in paddy fields have a significant impact on reducing water and energy consumption and can be beneficial from an energy consumption perspective in the northern rice-growing regions of the country. Additionally, the use of organic fertilizers can reduce the energy consumption associated with chemical fertilizers, which could be favorable for the sustainability of the regional agroecosystem and rice cultivation systems. Keywords: Electricity, Energy productivity, Fossil fuel, Energy use efficiency. |
