Environmental assessment of N fertilizer management practices

Transcription

1 Environmental assessment of N fertilizer management practices Joachim Lammel and Frank Brentrup Yara International Research Centre for Plant Nutrition Hanninghof, Germany

2 Contents Introduction environmental impacts and benefits of N fertilizer use Life Cycle Assessment (LCA) a methodology for the holistic environmental analysis of products and processes Environmental analysis of different N fertilizing intensities Regional adoption of the LCA methodology Summary Date: Page: 2

3 A N-fertilizer s life-cycle and some of its interactions with the environment N 2 CO 2, N 2 O, CO 2, NOx, NH 3, NO 3, N 2 O, N 2 Biomass Production Logistic Application Uptake Natural gas (feedstock) Fuel Minerals Fuel Fuel CO 2 Date: Page: 3

4 Environmental effects of N fertilizer use Impacts Eutrophication Nitrate leaching Ammonia Volatilisation Acidification Ammonia Volatilisaton Global warming CO2 emissions N2O emissions Benefits Biomass production Food, Feed, Energy Land preservation Carbon fixation Date: Page: 4

5 Contents Introduction environmental impacts and benefits of N fertilizer use Life Cycle Assessment (LCA) a methodology for the holistic environmental analysis of products and processes Environmental analysis of different N fertilizing intensities Regional adoption of the LCA methodology Summary Date: Page: 5

6 Life Cycle Assessment = LCA Definition: LCA is an inventory and evaluation of environmental impacts (emissions and resource consumption) along the life-cycle of a product For fertilizer: from raw material extraction, through fertilizer production to uptake by crop LCA is suitable to assess environmental impacts because: the entire production system is considered and all single environmental effects are included and evaluated, conclusive indicators are calculated. The LCA methodology is standardized (ISO/DIN series) Application to compare alternatives and /or to identify hot-spots Date: Page: 6

7 Life Cycle Assessment of arable production Raw material extraction Fossil fuels Minerals Production & transportation Fertilizer Pesticides Machinery Seeds Arable farming Tillage Sowing Plant nutrition Plant protection Harvest Inventory of environmental impacts (per t grain) Emissions (NO 3, NH 3, N 2 O, CO 2 etc.) and Resources (Oil, gas, land etc.) Wheat grain Date: Page: 7

8 The single impacts are combined into indicators for environmental effects Inventory of environmental impacts Eutrophication (PO 4 - / NOx-equiv.) NO 3 NH 3 N 2 O CO 2 CH 4 NOx SO 2 N tot P tot Arable land Oil Gas Coal Acidification (SO 2 -equiv.) Global warming (CO 2 -equiv.) Land use (m 2 *a) Energy consumption (MJ) Date: Page: 8

9 The EcoX method has been developed to aggregate different environmental effects Eutrophication Acidification Environmental index EcoX Land use Global warming Date: Page: 9

10 LCA of wheat production at different nitrogen application rates Yield response in the long-term Broadbalk experiment, Rothamsted/UK, different N rates since 1856 Grain yield (t/ha) Optimum yield Economic optimum N rate kg N/ha Date: Page: 10

11 Results from the Life Cycle impact assessment ha / t grain Land use kg PO 4 -equivalents / t grain Eutrophication of water kg CO 2 -equivalents / t grain Global warming kg SO 2 -equivalents / t grain Acidification Date: Page: 11

12 Today in Africa about 2 mio tons of cocoa beans are produced on about 5 mio ha other crops Average yield 400 kg / ha = 0,4 x ha Date: Page: 12

13 2 mio tons of cocoa beans can be produced on 50 % of the land that is planted today other crops Land for biodiversity? With intensification Average yield 800 kg / ha = 0,8 x ha Date: Page: 13

14 Results from the Life Cycle impact assessment ha / t grain Land use kg PO 4 -equivalents / t grain Eutrophication of water kg CO 2 -equivalents / t grain Global warming kg SO 2 -equivalents / t grain Acidification Date: Page: 14

15 Global Warming - Contribution of the different GHGs 500 kg CO 2 -equivalents / t grain kg N/ha N2O CO2 Date: Page: 15

16 CO2 balance of wheat produced at different N-fertilizer rates t CO2/ha ,9 11,2 11 3,3 3,3 3,3 3,3-0,7-0,7-0,7-0,7-1,3-2,5-3,7 N 0 N 96 N 192 N 288 CO2 fixation in additional biomass due to N fertilizer CO2 fixation in biomass without N fertilizer CO2 emissions: On-field activities N-fertilizer * * incl. N2O (1,25%) Yield response in the long-term Broadbalk experiment, Rothamsted/UK, different N rates since 1856 Date: Page: 16

17 CO2 balance of wheat produced at optimum N rate with different N2O emission factors t CO2/ha ,2 11,2 3,3 3,3-0,7-0,7-1,34-1,34-0,9-3,7 N % N2O N 192 4% N2O CO2 fixation in additional biomass due to N fertilizer CO2 fixation in biomass without N fertilizer CO2 emissions: On-field activities N-fertilizer Yield response in the long-term Broadbalk experiment, Rothamsted/UK, different N rates since 1856 Date: Page: 17

18 Energy balance of an arable production system Raw material extraction Production & transportation: Fertilizer Pesticides Machinery and seeds Arable farming: Tillage and seeding Plant nutrition Plant protection Harvest Energy balance: Energy consumption and Energy production (biomass yield) Biomass Date: Page: 18

19 Energy balance of wheat produced at different N-fertilizer rates GJ/ha N 0 N 96 N 192 N 288 Energy content in additional biomass with N fertilizer Energy content in biomass without N fertilizer Energy input: On-field activities N-fertilizer Yield response in the long-term Broadbalk experiment, Rothamsted/UK, different N rates since 1856 Date: Page: 19

20 Contents Introduction environmental impacts and benefits of N fertilizer use Life Cycle Assessment (LCA) a methodology for the holistic environmental analysis of products and processes Environmental analysis of different N fertilizing intensities Regional adoption of the LCA methodology Summary Date: Page: 20

21 Results of the Life Cycle impact assessment ha / t grain Land use kg PO 4 -equivalents / t grain Eutrophication of water kg CO 2 -equivalents / t grain Global warming kg SO 2 -equivalents / t grain Acidification Date: Page: 21

22 The EcoX method has been developed to aggregate different environmental effects Eutrophication Acidification Environmental index EcoX Land use Global warming Date: Page: 22

23 The EcoX method is based on a weighting of the different effects Weighting principle: Distance-to-Target Example: Global warming: Current situation in EU15 (EMEP, 2002): Target value for EU15 (Kyoto-Protocol, 1997): 3,93 Bio t CO 2 -equiv./year 3,68 Bio t CO 2 -equiv./year 3,93 Bio t CO 2 -equiv./year = 1,07 = weighting factor for global warming 3,68 Bio t CO 2 -equiv./year Date: Page: 23

24 The EcoX method is based on a weighting of the different effects Weighting principle: Distance-to-Target Weighting factors (for EU15): Global warming: 1,07 (Kyoto-Protokoll, 1998) Acidification: 1,34 (UN-ECE/CLRTP convention, 1999) Eutrophication, water: 1,36 (OSPAR/HELCOM conventions, 1995/2001) Eutrophication, land: 1,26 (UN-ECE/CLRTP convention, 1999) Land use: 1,00 (provisional: maintaining current status) Date: Page: 24

25 The EcoX method is based on a weighting of the different effects Application of the weighting factors, e.g. global warming: normalised value x weighting factor = environmental index (EcoX) 0,032 x 1,07 = 0,034 EcoX / t grain Result after weighting for 192 kg N/ha: Global warming: 0,032 x 1,07 = 0,034 Acidification: 0,028 x 1,34 = 0,038 Eutrophication, water: 0,050 x 1,36 = 0,068 Eutrophication, land: 0,026 x 1,26 = 0,033 Land use: 0,048 x 1,00 = 0, ,221 EcoX / t grain Date: Page: 25

26 Results of a LCA study on different N fertilizer rates Environmental index (EcoX / t grain) Eutrophication (water & land) Acidification Global warming Land use kg N/ha Yield response in the long-term Broadbalk experiment, Rothamsted/UK, different N rates since 1856 Date: Page: 26

27 Contents Introduction environmental impacts and benefits of N fertilizer use Life Cycle Assessment (LCA) a methodology for the holistic environmental analysis of products and processes Environmental analysis of different N fertilizing intensities Regional adoption of the LCA methodology Summary Date: Page: 27

28 Regional adoption of the LCA methodology Impact assessment Environmental impacts may differ regionally e.g. because of different environmental background. (e. g. ammonia deposition may have little negative impact on arable land, while the impact is large on natural ecosystem or on oligotrophic lakes) Normalisation Emissions from agricultural may be more relevant in regions where agriculture is the major contributor to environmental issues Weighting If environmental targets are used for weighting, these should be valid for the region of application. Some targets like GHG emissions are global Date: Page: 28

29 LCA can be regionally adopted example AN or Urea in different countries in Europe Environmental index (EcoX / t grain) 1.2 Field in Sweden 1.0 Field in UK Field in Spain AN Urea AN Urea AN Urea Eutrophication (water & land) Acidification Global warming Land use Date: Page: 29

30 Conclusion The environmental impacts of nitrogen fertilizer use can be best described by a holistic consideration of all effects related to the use of N fertilizer Life Cycle Assessment (LCA) is the appropriate methodology for the holistic environmental analysis of products and processes The LCA methodology is well documented and the data bases are available More LCA studies should be conducted in order to prioritise the right issues to further improve nitrogen fertilizer management Date: Page: 30