Energy and efficiency of use could make a

Energy plays a determinant role in the economic
growth of countries and its importance is constantly increasing. Scientific forecasts
and analysis of energy consumption will be of great significance for the planning
of energy strategies and policies (Liang et al., 2007). Agriculture is a main
energy resource consumer. Increasing use of energy inputs in agriculture has
led to numerous environmental problems such as high consumption of non-renewable
energy resources, loss of biodiversity and pollution (Nemecek et al., 2011). Non-renewable
energy includes diesel, chemicals, fertilizers and machinery, and renewable
energy consists of human labor, seeds, and manure (Mohammadi et al., 2008). Additional use of non-renewable energy sources
to boost agricultural productions in developing countries with low levels of
technological knowledge not only results in environmental deterioration but
also confronts us with the dilemma of a rapid rate of depletion of energetic
resources (Fadai, 2007). Energy analysis of agricultural ecosystems seems to be
a promising approach to investigate and assess the energy use efficiency,
environmental problems and their relations to sustainability (Giampietro et
al., 1992). Wider use of renewable energy sources, enhance in energy supply and
efficiency of use could make a valuable contribution to meeting sustainable
energy development targets (Streimikiene et al., 2007). Energy use patterns and
contribution of input energy depend on farming systems, growing season of crop and
farming conditions (Hatirli et al., 2006). Efficient use of energy will
minimize environmental problems, prevent the destruction of natural resources, and
promote sustainable agriculture as an economical production system (Erdal et
al., 2007). Moreover, efficient use of energy is one of the principal
requirements of sustainable agriculture. Energy input-output analysis is
usually used to evaluate the efficiency and environmental impacts of production
systems. Energy consumption by the agriculture sectors can be broadly categorized
into direct and indirect energy use. Agriculture uses energy directly as fuel
or electricity to operate machinery and equipment, to heat or cool buildings
and for lighting on the farm and indirectly in the chemical fertilizers, seed
production, machinery and biocides produced off the farm (Uhlin, 1998; Ozkan et
al., 2004a).

Global warming is one of the most
important issues in recent time. As a report, activities
contribute a large percentage of greenhouse gas GHG emissions (Guo and Zhou 2007). The global mean temperature has
increased during the past 100 years and raised concerns over global warming and
uncertainty over future impacts on the climate (Pimentel et al., 1996). Consumption
of fossil fuels that is required for crop production results in the emission of
carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4)
that so-called GHG. Therefore, the enhancement of energy efficiency not only helps
in improving competitiveness through cost reduction but also results in minimized
GHG emissions (Alluvione et al., 2011). Appropriate coordination of the affairs
in agriculture by the management and designing a proper cultivation pattern in
regions can be one solution to the energy consumption and GHG emission
reductions. This study was aimed to determine energy efficiency, GHG emission
such as CO2, N2O and CH4 and also global
warming potential (GWP) in some crop such as rain-fed
barley and wheat, canola, irrigated barley and wheat, bean, sugar beet, and potato
using TOPSIS method in Azna, Lorestan province, Iran.