پژوهشهای زراعی ایران (Jun 2023)
Evaluating the Sustainability of Canola Agroecosystems Using Energy Analysis, Carbon Footprint, and Greenhouse Gases
Abstract
IntroductionIn recent decades, the need for increased food production has resulted in the expansion of intensified agriculture practices characterized by high consumption of inputs, thereby reducing agricultural sustainability. The agricultural sector's contribution to the world's energy consumption, ecological footprint, and greenhouse gas emissions has grown substantially. Emissions of greenhouse gases have negative ecological effects, including climate change, global warming, and diminished sustainable development. In this sector, energy analysis and greenhouse gas emissions in ecosystems are the most common methods for assessing sustainability. This study was conducted to evaluate the sustainability of canola agroecosystems by analyzing energy consumption, carbon footprint, and greenhouse gas emissions.Methods and MaterialsThe study was conducted using a questionnaire in Kalaleh County, in Golestan province, and gathering information from Golestan Agricultural Jihad Organization, during 2018-2019. The number of samples was determined by the Cochran formula. Accordingly, 50 farms were selected for canola cultivation. The questionnaire's reliability was determined to be 0.81. To calculate the energy indices, carbon footprint, and greenhouse gas emissions, after determining the most important inputs and output, first, their amounts were determined in each of the 50 farms and then their average was calculated. The energy equivalent of each input and output was calculated by multiplying its raw value by the corresponding energy conversion factor. The carbon footprint of the canola system was calculated as the amount of land required to absorb the environmental pollution caused by input and resource consumption. Carbon uptake in canola agroecosystems served as the basis for evaluating the carbon footprint and consequently the sustainability of this study. Also, the amount of greenhouse gases produced was determined by multiplying the raw values of the consumed inputs by their emission coefficient. Results and DiscussionIn canola agroecosystems, the total energy input was calculated to be 13,200 MJ ha-1, the total energy output was 63,400 MJ ha-1, the energy use efficiency was 4.8, and the energy productivity was 0.17 kg MJ-1. In addition, the ecological footprint and global warming potential were 0.99 gha and 779.03 CO2e ha−1, respectively. In canola production, fossil fuel and nitrogen fertilizer inputs contributed the most to ecological footprint and global warming potential respectively. Reducing the number of machines entering the farm through the application of conservation tillage methods and the modernization of machines can be effective in reducing the consumption of this input. Due to the non-renewability of this input, reducing its consumption is effective in reducing both economic costs and environmental pollution. Consuming as much livestock manure (cattle) as possible and implementing crop rotations with legumes such as soybeans that can grow well in this area is effective in supplying soil nitrogen and reducing the need for chemical fertilizers. ConclusionAnalysis of energy indices, such as energy efficiency and net energy, revealed that energy loss in the canola farming ecosystem is low and that the system's sustainability is adequate. Evaluation of carbon footprint revealed that the value of this index for canola production in the county of Kalaleh was less than the ecological capacity of each hectare of land used for canola production, indicating the environmental sustainability of canola production in the county of Kalaleh. In general, canola agroecosystems in the county of Kalaleh were sustainable based on terms of all three indices: net energy, carbon footprint, and global warming potential. Due to the large proportion of two inputs, fossil fuel, and nitrogen fertilizer, in these indices and their significant impact on production sustainability, consumption management of these inputs and training and justification of farmers are recommended to increase production sustainability.
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