Introduction: In the current era, ecological degradation, depleted resources, and insufficient food supplies have linked energy consumption and greenhouse gas (GHG) emissions to the long term sustainability of agricultural systems. In the transition from traditional to modern agriculture, commercial energy use has increased sharply, along with higher production costs and declining energy reserves. Both direct effects and indirect energy consumption have contributed significantly to major food production. Direct energy is required to perform various tasks related to crop production processes, such as land preparation, irrigation, inter-cultivation, harvesting, and transportation of agricultural inputs and products. The specific energy consumption of a major cropping system depends on factors such as soil type, machinery, electricity, fossil fuels, chemicals, fertilizers, harvesting, and post‑harvest operations. Crop management practices can also be beneficial and play an important role in increasing energy productivity. Energy assessment in agricultural systems can help develop and improve environmentally friendly and energy‑efficient agricultural technologies. Agricultural mechanization, increased fertilizer use, and expanded irrigation have all led to a significant increase in energy consumption in agriculture. Intensive agriculture has become one of the main causes of the energy crises and global warming effects we observe today, and it should be considered a serious threat to sustainable agricultural development.
Materials and methods: A study was conducted to evaluate the energy consumption, energy balance, and greenhouse gas emissions in sugar beet production in Gorgan County. This research was carried out on 25 square meters of sugar beet fields during the 2018–2019 cropping year. First step: After selecting the target fields, all agricultural operations were recorded one by one. Also, the consumption rates of inputs in each field were noted. During the activity, the yield of the investigated fields was recorded. In the second step, based on the amount of fuel and input consumption for each type of agricultural operation performed, and considering the corresponding coefficients, the input energy and greenhouse gas emissions per hectare were analyzed.
Results: According to the results, 240 liters of diesel and 25,476 megajoules of energy were required to produce each hectare of sugar beet, which resulted in greenhouse gas emissions of 2,687 kilograms of carbon dioxide equivalent. The output energy was also 202,500 megajoules per hectare. Accordingly, the ratio of output energy to input energy was calculated as 94.7. Also, the net energy of sugar beet was estimated to be 177,024 megajoules per hectare, energy efficiency was 92.1 kilograms per megajoule, and specific energy was 52.0 megajoules per kilogram. Based on the results, the greenhouse gas emissions for each hectare of sugar beet were estimated to be 2,687 kilograms of carbon dioxide equivalent. Also, on average, 105 grams of greenhouse gases were emitted per megajoule of energy consumed per hectare of sugar beet, which was estimated to be 13 grams for output energy.
Conclusion: Finally, it can be stated that the consumption of chemical fertilizers, especially nitrogen fertilizers, as well as fossil fuels, accounted for a significant portion of energy consumption and greenhouse gas emissions. Reducing their use can be a step toward decreasing energy consumption and greenhouse gas emissions in sugar beet production. |
