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Application of LCA methodology to agricultural production: an example of sugar beet production with different forms of nitrogen fertilisers. Life Cycle Assessment Merike Soodla. Materials and methods. LCA concept consists of four major steps: Goal and scope definition; Life Cycle Inventory;
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Application of LCA methodology to agricultural production: an example of sugar beet production with different forms of nitrogen fertilisers Life Cycle Assessment Merike Soodla
Materials and methods • LCA concept consists of four major steps: • Goal and scope definition; • Life Cycle Inventory; • Life Cycle Impact Assessment; • Interpretation.
The goal of the analysis (1) • To quantify and to evaluate the impact of the choice of different N fertilisers on the entire environmental burden associated with a sugar beet production system. • Three different N fertilisers were used at optimum N rates: • Calcium ammonium nitrate – CAN • Urea ammonium nitrate solution – UAN • Urea • All environmental impacts are related to the production of one tonne of extractable sugar, which is the functional unitfor this analysis. • The analysis is based on a field trial, which have been conducted in the north-eastern part of Germany in 1998.
Exploration, processing and transportation of raw materials • fossil fuels • process gas • Inputs • Energy • Land • Production and transportation of • mineral fertiliser • plant protection substances • seeds • machinery • Outputs • Emissions to air, water and soil • Arable farming • soil preparation • fertilisation • plant protection • harvest The goal of the analysis (2) • Description of the sugar beet system and its sub-systems
Life Cycle Inventory (1) Environmental impacts (all the inputs and outputs) associatedto the production of sugar beet
Life Cycle Inventory (2) Nitrogen inputs (+) and outputs (-) in the N balance • Into the system (+): • N min in soil in spring • Fertiliser N • Atmospheric N deposition • Net N mineralization during vegetation • Mineralization of N from sugar beet leaves during winter • Out of the system (-): • NH3 volatilisation • N2O emission • N removal with beets • N content of leaves • N uptake of winter wheat in autumn
Life Cycle Impact Assessment (1) • For this study the Eco-indicator 95 method has been chosen to analyse the environmental impacts of sugar beet production as well documented and regularly used method for the LCA studies. • The resulting index is called Eco-indicator value. • The higher the Eco-indicator value the stronger is the total environmental impact of an analysed system.
Life Cycle Impact Assessment (2) • In the first step (called as classification/characterization) the inventory data were aggregated to effect scores using the equivalence factors: InterventionsEquivalence factorEffects CO2 1 N2O 310 global warming [CO2 equiv.] CH4 21 NO3 0,42 N tot 0,42 eutrophication [PO4 equiv.] P tot 3,06 0,33 NH3 0,13 1,88 NOx 0,7 acidification [SO2 equiv.] SO2 1 VOC 0,42 summer smog [C2H4 equiv.]
Life Cycle Impact Assessment (3) • During the second step (normalization) the contribution of the analysed system to the total extent of the environmental effects in Europe was examined – the global environmental effect potential of the system was divided by the total environmental effect potential in Europe. • The total extent of different environmental problems was expressed as environmental effect caused by one person per year. • In the following, weighting step, the different level of severeness of the environmental effects were considered by multiplying each normalized effect value by a weighting factor.
Life Cycle Impact Assessment (4) • Weighting factors for sugar beet production according to the Eco-indicator 95 method
Results of the analysis (1) • The obtained Eco-indicator values were clearly different for the N fertilisers used in the sugar beet trial due to the following: • Differences in the CO2 emissions due to the differences in the energy consumption during fertilisers production; • N2O emissions are bigger for CAN fertiliser system because of the production of nitric acidduring fertiliser production process; • NH3 emissions are higher for systems of urea containing fertilisers; • NO3 leaching rate differs due to the differences in the N removal with beets; • Differences in fossil fuel consumption due to the different energy consumption during fertilisers production.
Results of the analysis (2) • In this analysis the contribution of the sugar beet production system to the following environmental effects was examined: global warming, acidification, eutrophication and summer smog. • Contribution of the fertilising systems to the environmental effects in Europe show that the biggest concerns are related to the eutrophication and acidification, smaller concern relate to the global warming and summer smog formation has the lowest environmental effect.
Results of the analysis (3) • The lowest Eco-indicator value has been calculated for the calcium ammonium nitrate (CAN) system and the highest for urea system. This is due to the differences in the ammonia volatilisation after application of N fertiliser and the differences in acidification and eutrophication potential between fertilising systems.
Conclusion • Thus the LCA method Eco-indicator 95 has proven to be applicable to analyse the environmental impact of agricultural systems although it has some constraints. • Besides the applied N fertiliser rate and application technique, the choice of the a mineral N fertiliser can clearly influence the environmental impact associated with the sugar beet production.