Arable land as carbon sink - including carbon sequestration in biogas systems studies LOVISA BJÖRNSSON

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1 Arable land as carbon sink - including carbon sequestration in biogas systems studies LOVISA BJÖRNSSON

2 750 billion t C Soil organic carbon 550 billion t C billion t C 45% of the soils in the EU have low or very low (0-2%), and declining, soil organic carbon (SOC) content soil resources in many parts of Europe are being overexploited, degraded and irreversibly lost due to inappropriate land management practices A healthy, fertile soil is at the heart of food security Kätterer & Andrén (1998) Long-term agricultural field experiments in Northern Europe: Analysis of the influence of management on soil carbon stocks using the ICBM model. Agriculture, Ecosystems and Environment. 72, Jones et al. (2012) The state of soil in Europe. Report EUR EN. JRC, Ispra, Italy.

3 Specializing agriculture C2 C1

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6 Current SOC development SOC content [%] 2,5 2,0 1,5 Annual GHG emissions due to SOC losses C2: 1000 kg CO 2 -eq ha -1 year -1 C1: 140 kg CO 2 -eq ha -1 year -1 C2 current C1 current 1, Time [years]

7 Grass SOC losses are on average low for Sweden, and increasing grass cultivation area has been identified as one of the major causes to this development. Poeplau, C., Bolinder, M.A., Eriksson, J., Lundblad, M., and Kätterer, T. (2015) Positive trends in organic carbon storage in Swedish agricultural soils due to unexpected socio-economic drivers. Biogeosciences Discussions, 12(5)

8 Grass SOC losses are on average low for Sweden, and increasing grass cultivation area has been identified as one of the major causes to this development. Million animals 1,8 1,6 1,4 1,2 1,0 0,8 0,6 0,4 0,2 Milking cows Horses Poeplau, 0,0 C., Bolinder, M.A., Eriksson, J., Lundblad, M., and Kätterer, T. (2015) Positive trends in organic carbon storage in Swedish 1940agricultural 1960 soils 1980 due to unexpected socio-economic drivers. Biogeosciences Discussions, 12(5)

9 The studied crop rotations Reference scenario C1 CURRENT (ABOVE) MODIFIED (BELOW) 4-year crop rotation typical for the region -winter oil seed rape -winter wheat -winter wheat -oats C2 CURRENT (ABOVE) MODIFIED (BELOW) Conventional cultivation, mineral fertilizer Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 One year in a five year crop rotation Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Winter wheat W oilseed rape Sugar beet Oats Spring barley Grass

10 Grass as biogas feedstock C1 C2

11 Soil carbon development 2,5 SOC content [%] 2,0 1,5 C2 current C1 current 1, Time [years]

12 Soil carbon development 2,5 SOC content [%] 2,0 1,5 C2 modified C2 current C1 modified C1 current 1, Time [years]

13 Soil carbon development 2,5 SOC content [%] 2,0 1,5 C2 modified + biofertilizer C2 modified C2 current C1 modified + biofertilizer C1 modified C1 current 1, Time [years]

14 GHG perspective 2,0-0.8 t -0.5 t GHG emissions [t CO 2 -eq per hektare and year] 1,5 1,0 0,5 0,0-0,5 Cultivation inputs Field emissions Cultivation inputs Field emissions Cultivation inputs Field emissions Cultivation inputs Field emissions C1 current C1 modified C2 current C2 modified -1,0 Materials & mineral fertilizer Diesel & other energy input N2O mineral fertilizer N2O bio fertilizer N2O crop residues N2O indirect SOC

15 GHG perspective 2,0 GHG emissions [t CO 2 -eq per hectare and year] 1,5 1,0 0,5 0,0-0,5-1,0-1,5 C1 biogas C2 biogas GHG emissions [t CO 2 -eq ha -1 a -1 ] Cultivation The biogas system C ,7 C2-0,5-1,1-2,0 Biogas production Replacing lost crops Biogas replaces diesel

16 EU RED C1 C2 50 GHG emission [g CO 2 -eq (MJ) -1 ] % -10

17 To summarize A sustainable use of arable land should give the lowest possible contribution to greenhouse gas emissions while food production is safeguarded in the long term The present, specialized agricultural practice is not sustainable in the long run: Carbon emissions and eventually decreasing crop yields To introduce grass cultivation in cereal crop rotations is one approach that can reverse the present carbon loss from arable land Important to consider the conflict between the use of arable land for food/feed crops and biomass for energy purposes in any scenario involving the use of land or biomass The complexity in sustainability assessments of arable land use requires an improved methodological framework Scientifically sound assessments, taking local conditions and spatial perspectives into account, are important in future policies regarding sustainable use of arable land

18 Read more Lovisa Björnsson, Thomas Prade & Mikael Lantz (2016) Grass for biogas - Arable land as carbon sink. Report 2016:280. Energiforsk, Stockholm/Malmö, Sweden. Thomas Prade (2016) Soil organic carbon development in a cereal-dominated region Impact of crop rotation diversification. 10th International Conference on LCA of Food, October 2016, Dublin, Ireland. Lovisa Björnsson & Thomas Prade (2016) Arable land as carbon sink a regional case study on greenhouse gas emission impact of diversifying cereal based crop rotations. 10th International Conference on LCA of Food, October 2016, Dublin, Ireland. Lovisa Björnsson, Thomas Prade & Mikael Lantz (2016) Åkermark som kolsänka en utvärdering av miljö- och kostnadseffekter av att inkludera gräsvall för biogas i spannmålsrika växtföljder. Rapport Nr 98, Miljö- och energisystem, Lunds Universitet, Lund, Sweden.

19 Professor Environmental and Energy Systems Studies