Mohammad Hosein Torabi; Afshin Soltani; Salman Dastan; Hosein Ajam Norouzi
Volume 16, Issue 4 , January 2019, , Pages 187-212
Abstract
Introduction: Environmental assessment of the life cycle of crops in production systems is an accepted method for achieving agricultural sustainability. Moreover, the agricultural sector has a significant contribution to greenhouse gas emissions and global warming. Hence, improving agricultural operations ...
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Introduction: Environmental assessment of the life cycle of crops in production systems is an accepted method for achieving agricultural sustainability. Moreover, the agricultural sector has a significant contribution to greenhouse gas emissions and global warming. Hence, improving agricultural operations is an appropriate way to mitigate the effects of climate change. Therefore, the aim of this research was the environmental assessment of different scenarios of the production of improved rice cultivars. Material and methods: After preliminary evaluation and consultation with rice specialists, 100 paddy fields were selected for semi-mechanized planting method and 100 paddy fields for traditional planting method in Sari region from 2015 to 2016. After recording the data, each planting method was converted into four planting systems based on agronomic management and input consumption, which formed a total of eight scenarios. Four scenarios of the semi-mechanized method were systems of low-input (SL), conservation (SCI), conventional (SCII) and high-input (SH). Four scenarios of the traditional method were systems of low-input (TL), conservation (TCI), conventional (TCII) and high-input (TH). Results and discussion: The results indicated that the average paddy yield in eight scenarios was 6418 kg.ha-1. The average input energy in eight scenarios was 28138.93 MJ.ha-1, which contained 45.44% renewable (biologic) energy and 54.56% non-renewable (industrial) energy. The highest input energy was observed in scenarios IV and VIII, which was related to the SH in both planting methods. The average output energy in eight scenarios was equal to 197076 MJ.ha-1. The highest output energy was obtained in scenarios III, IV, VII and VIII. The average energy productivity in the eight scenarios was equal to 0.23 kg.MJ-1 that the least amount was obtained in both planting methods and the other scenarios were on the same level. The average CO2 emissions in all eight scenarios were 1120.37 kg CO2.eq ha-1, which had the highest share related to seed, fuel, and machinery. In terms of global warming potential per unit area, scenario VIII was ranked first and scenario IV ranked second. The highest global warming potential per grain weight and GWP per input energy were achieved in scenarios I and V. The highest heavy metal emission into water and soil was observed in the SH and SCII, respectively. The highest net primary productivity (NPP) in production scenarios was related to SCII and SH, which was higher in the semi-mechanized method than the traditional method. In both planting methods, the most relative carbon inputs (Ri) were obtained in scenarios of the SH (I and V). With regard to input-output carbon and net carbon in eight scenarios, the average sustainability index was 4.66. The highest sustainability index was observed in scenario II (5.05), which was related to the conservation system. The scenarios V, I, III and VI were next ranked in terms of the sustainability index. In fact, the correct management of the paddy field in the SCI has led to a reduction in emissions of environmental pollutants. Conclusion: According to the findings, SL and SCI were closer to sustainable development indicators in both methods. Furthermore, the economic efficiency of rice production was more important to farmers than environmental sustainability and energy efficiency. Hence, using the findings of this research can be very effective in increasing environmental sustainability and reducing the environmental impacts of chemical inputs and achieving agricultural sustainability.
Salman Dastan; Afshin Soltani; Ghorban Noormohamadi; Hamid Madani; Reza Yadi
Volume 14, Issue 1 , April 2016, , Pages 19-28
Abstract
Optimal management approaches can be adopted in order to increase crop productivity and lower the carbon footprint of grain products. The objective of this study was to estimate the carbon (C) footprint and global warming potential of rice production systems. In this experiment, rice production systems ...
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Optimal management approaches can be adopted in order to increase crop productivity and lower the carbon footprint of grain products. The objective of this study was to estimate the carbon (C) footprint and global warming potential of rice production systems. In this experiment, rice production systems (including SRI, improved and conventional) were studied. All activities, field operations and data in production methods and at different input rates were monitored and recorded during 2012. Results showed that average GWP across production systems was equal to 2803.25 kg CO2-eq ha-1. The highest and least GWP were observed in the SRI and conventional systems, respectively. GWP per unit energy input was the least and most in SRI and conventional systems, respectively. Also, the SRI and conventional systems had the maximum and minimum GWP per unit energy output, respectively. SRI and conventional system had the greatest and least GWP per unit energy output, respectively. Therefore, the optimal management approach found in SRI resulted in a reduction in GHGs, GWP and the carbon footprint.
Mohammad Hossein Rajabi,; Afshin Soltani,; Bita Vhidnia,; Ebrahim Zeinali; Elias Soltani
Volume 9, Issue 2 , January 2012
Abstract
With regard to the careless consumption of fossil fuels in Iran and the resulting greenhouse gas emissions and related risks to the environment and human health, many attempts are being undertaken to try to control this consumption. The agricultural sector is no exception to this vital and important ...
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With regard to the careless consumption of fossil fuels in Iran and the resulting greenhouse gas emissions and related risks to the environment and human health, many attempts are being undertaken to try to control this consumption. The agricultural sector is no exception to this vital and important issue. The objectives of this research were: (1) to determine amount of fuel consumption and related energy use in wheat fields in Gorgan Province, (2) to estimate the environmental impact of the consumed fuel using global warming potential (GWP), and (3) to explore options to optimize fuel consumption. Data were gathered from six representative fields by monitoring production practices and inputs used. Data were analyzed with regard to fuel consumption, energy inputs related to fuel consumed and greenhouse gas emissions from the consumed fossil fuels. Fuel ranged between 53 to 123 L ha-1 and the energy from the consumed fuel varied between 2026 to 4664 MJ ha-1. Results indicated that seedbed preparation had the highest rate of fuel consumption (59.5 % of total) followed by harvesting, irrigation and sowing operations at 10.5, 9.4 and 8.1 %, respectively. The average of greenhouse gas emissions (CO2, CH4 and N2O) from the consumed fossil fuels was estimated at 244 kg equivalent CO2 ha-1. It was concluded that through better farm management and more research it is possible to reduce fuel consumption and greenhouse gas emissions.
