Comparison of input, output energy and global warming potential in rainfed wheat and barley in Aq-Qala (Golestan province)

Introduction:
In recent years, energy consumption in agriculture has increased dramatically, and modern agriculture has become very scarce in energy. Most of the energy used to produce agricultural products is due to the use of inputs such as machinery, fossil fuels, fertilizers and pesticides, that inappropriate use of these inputs while reducing energy efficiency in production also causes problems for human health and the environment. At the moment, due to the energy crisis in the world, it is necessary to study more about energy consumption and find solutions for its optimal use (Darlington, 1997). This study was conducted to identify the energy evolution and global warming potential in wheat and barley production in northern lands of Gorgan plain and in the city of Aq-Qala. So that appropriate strategies can be identified to prevent energy wasting and reduce the environmental impact of resources.
Material and methods:
For this study 95 and 83 farmers were selected for wheat and barley production in Aq-Qala city, respectively. The data including (machines, seeds, fertilizers, fuel and pesticides) were collected by questionnaire. Then fuel, input and output energy, energy evaluation indices and global warming potential (kg CO2.ha-1) were calculated by related coefficients (Soltani et al., 2013).
Results and discussion:
The results showed that the highest direct input energy in wheat and barley production belonged to fuel consumption were 38.8% and 46.8% respectively. Also, the highest indirect input energy was obtained with 31.3 and 19.1 percent for nitrogen fertilizer for wheat and barley fields, respectively. The ratio of the energy output to the input for rainfed wheat and rainfed barley were calculated 5.01 and 5.03, respectively. Also, global warming potential in wheat and barley production was 943.9 and 739.1 (kg eq-CO2 ha-1), respectively. In another study, greenhouse gas emissions for wheat production in Golestan province were estimated about 1200 kg CO2.ha-1 (Rezvantalab et al., 2015). Also, the results showed that increased fuel and fertilizer consumption will increase the amount of input energy in both crop production and increase the production of greenhouse gases. Therefore, the use of more efficient machinery and equipment, which reduces fuel consumption, and also, considering proper crop rotation and using organic fertilizers can reduce energy consumption, increase energy efficiency and reduce the global warming potential of rainfed wheat and rainfed barley production.
Conclusion:
The results showed that the fuel consumed in both products had the highest input energy input, followed by fertilizer, especially nitrogen fertilizer, Therefore, the reduction of fuel consumption by using combinators and the use of protection culture systems (minimum tillage) is recommended to reduce the amount. It is also recommended to observe crop rotation and rotation with cover crops that are able to stabilize nitrogen as one of the ways to reduce fertilizer use. It is suggested that yield increase by improving management operations, optimum use of fertilizers, pest control, and then, will improve energy efficiency.