Aus dem Institut für Landwirtschaftliche Betriebslehre (410b) Universität Hohenheim Fachgebiet: Analyse, Planung und Organisation der landwirtschaftlichen Produktion Prof. Dr.sc.agr. Drs.h.c. Jürgen Zeddies Biogenic Greenhouse Gas Emissions from Agriculture in Europe – Quantification and Mitigation Dissertation zur Erlangung des Grades eines Doktors der Agrarwissenschaften der Faktultät IV – Agrarwissenschaften II (Agrarökonomie, Agrartechnik und Tierproduktion) von Annette Freibauer aus Donauwörth 2002 Die vorliegende Arbeit wurde am 18.2.2002 in der Fakultät IV – Agrarwissenschaften II der Universität Hohenheim als “Dissertation zur Erlangung des Grades eines Doktors der Agrarwissenschaften” angenommen. Tag der mündlichen Prüfung: 2.4.2002 Dekan: Prof. Dr.sc.agr. S. Dabbert Berichterstatter, 1. Prüfer: Prof. Dr. Drs. H.c. Jürgen Zeddies, Institut für Landwirtschaftliche Betriebslehre (410b) Mitberichterstatter: PD Dr.-Ing. Martin Kaltschmitt, Institut für Energetik und Umwelt, Leipzig 2. Prüfer: Prof. Dr. Karl Stahr, Institut für Bodenkunde und Standortslehre (310) 3. Prüfer: Prof. Dr. W. Claupein, Institut für Pflanzenbau und Grünland (340) Meinen Eltern Contents I Contents CONTENTS............................................................................................................................... I LIST OF FIGURES .................................................................................................................V LIST OF TABLES ................................................................................................................VII ABBREVIATIONS.................................................................................................................IX CONVERSION TABLE..........................................................................................................X 1 INTRODUCTION ............................................................................................................1 1.1 POLITICAL BACKGROUND.................................................................................................1 1.1.1 Climate policy.........................................................................................................2 1.1.2 Agricultural policy..................................................................................................4 1.2 MITIGATION OF GREENHOUSE GAS EMISSIONS .................................................................6 1.2.1 Carbon sequestration..............................................................................................6 1.2.2 Carbon substitution ................................................................................................8 1.2.3 Reduction of greenhouse gas emissions................................................................11 1.2.4 Comparison of strategies......................................................................................13 1.2.5 Indirect greenhouse gas emissions from agriculture............................................15 1.2.6 Potential and limitation of agriculture for greenhouse gas mitigation................16 1.3 AIM AND STRUCTURE.....................................................................................................17 1.3.1 Aim and scope.......................................................................................................17 1.3.2 Structure ...............................................................................................................19 REFERENCES ..........................................................................................................................21 2 POTENTIAL AND RISKS OF CARBON SEQUESTRATION IN THE BIOSPHERE...........................................................................................................................27 ABSTRACT .............................................................................................................................27 2.1 INTRODUCTION ..............................................................................................................27 2.1.1 Carbon stocks.......................................................................................................28 2.1.2 Carbon fluxes........................................................................................................28 2.1.3 Carbon sinks in the Kyoto Protocol .....................................................................29 2.1.4 Aim and scope.......................................................................................................29 2.2 OPTIONS FOR CARBON SEQUESTRATION.........................................................................29 2.2.1 Land use change ...................................................................................................30 2.2.2 Land management ................................................................................................31 2.3 POTENTIAL AND RISKS OF CARBON SEQUESTRATION......................................................32 II Contents 2.3.1 Methodology and assumptions..............................................................................32 2.3.2 Land use change....................................................................................................33 2.3.3 Land management.................................................................................................34 2.4 ENVIRONMENTAL EFFECTS OF CARBON SEQUESTRATION ...............................................37 2.5 UNCERTAINTIES IN CARBON SEQUESTRATION ................................................................37 2.6 CARBON SEQUESTRATION IN THE CONTEXT OF THE KYOTO PROTOCOL..........................38 2.7 CONCLUSIONS ................................................................................................................39 ACKNOWLEDGEMENTS...........................................................................................................40 REFERENCES ..........................................................................................................................40 3 GASEOUS NITROGEN COMPOUNDS IN THE LIFE CYCLE OF ENERGY CROPS .....................................................................................................................................43 ABSTRACT..............................................................................................................................43 3.1 INTRODUCTION...............................................................................................................43 3.2 METHODOLOGICAL BASIS ..............................................................................................44 3.2.1 Goal and scope definition .....................................................................................45 3.2.2 Inventory analysis .................................................................................................49 3.2.3 Impact assessment.................................................................................................51 3.2.4 Interpretation........................................................................................................52 3.3 RESULTS AND DISCUSSION .............................................................................................52 3.3.1 Inventory analysis .................................................................................................53 3.3.2 Impact assessment.................................................................................................56 3.3.3 Sensitivity analyses................................................................................................57 3.4 CONCLUSIONS AND OUTLOOK ........................................................................................60 ACKNOWLEDGEMENTS...........................................................................................................61 REFERENCES ..........................................................................................................................61 4 CONTROLS AND MODELS FOR ESTIMATING DIRECT NITROUS OXIDE EMISSIONS FROM TEMPERATE AND SUB-BOREAL AGRICULTURAL MINERAL SOILS IN EUROPE............................................................................................65 ABSTRACT..............................................................................................................................65 4.1 INTRODUCTION...............................................................................................................65 4.1.1 Controls of soilborne N2O emissions....................................................................66 4.1.2 Quantification of soilborne N2O emissions...........................................................69 4.2 MATERIAL AND METHODS .............................................................................................70 4.2.1 Nitrous oxide and site data...................................................................................71 4.2.2 Statistical analyses................................................................................................72 4.3 RESULTS.........................................................................................................................74 4.3.1 Homogeneous climatic groups..............................................................................74 4.3.2 Importance of controlling factors.........................................................................75 4.3.3 Combined effects...................................................................................................79