UNIVERSITÀ DEGLI STUDI DELLA TUSCIA DI VITERBO DIPARTIMENTO PER LA INNOVAZIONE NEI SISTEMI BIOLOGICI AGROALIMENTARI E FORESTALI Corso di Dottorato di Ricerca in Scienze Tecnologie e Biotecnologie per la Sostenibilità – Curriculum Ecologia Forestale e Tecnologie Ambientali – XXIX Ciclo SOIL ORGANIC CARBON, SOIL MICROBIAL COMMUNITIES AND PLANT BIOMASS CHANGES ALONG WOODY ENCROACHMENTS OVER ABANDONED PASTURES IN ITALY ( s.s.d. AGR/05) Tesi di dottorato di: Dott. Guido Pellis Firma Coordinatore del corso Tutore Prof. Mauro Moresi Prof. Dario Papale Firma Firma Co-tutore Dott. Tommaso Chiti Firma A.A. 2016/17 1 TABLE OF CONTENTS 1. LIST OF ABBREVIATIONS ...................................................................................................... 4 2. SHORT ABSTRACT ................................................................................................................... 7 3. KEYWORDS ............................................................................................................................... 8 4. EXTENDED ABSTRACT .......................................................................................................... 9 4.1. Introduction ........................................................................................................................... 9 4.2. Materials and Methods .......................................................................................................... 9 4.3. Results ................................................................................................................................. 11 4.4. Discussion ........................................................................................................................... 14 4.5. Conclusions and Future Perspectives .................................................................................. 16 5. INTRODUCTION ..................................................................................................................... 18 5.1. General considerations ........................................................................................................ 18 5.2. Terminology ........................................................................................................................ 18 6. STATE-OF-THE-ART .............................................................................................................. 21 6.1. Land-Use Change ................................................................................................................ 21 6.2. Establishment of woody plant species................................................................................. 21 6.3. The chronosequences approach ........................................................................................... 23 6.4. Vegetation and microbiology .............................................................................................. 24 7. AIMS OF THE STUDY ............................................................................................................ 26 8. MATERIALS AND METHODS ............................................................................................... 27 8.1. Sites selection ...................................................................................................................... 27 8.2. Sites description .................................................................................................................. 29 8.2.1. Castello Tesino ................................................................................................................. 29 8.2.2. Mel ................................................................................................................................... 32 8.2.3. Chianocco......................................................................................................................... 34 8.2.4. Firenzuola......................................................................................................................... 37 8.2.5. Farindola .......................................................................................................................... 39 8.2.6. Vastogirardi ...................................................................................................................... 41 8.2.7. Pignola ............................................................................................................................. 43 8.3. Soil sampling design ........................................................................................................... 45 8.4. Soil and litter sampling collection ....................................................................................... 47 8.5. Soil physical and chemical analyses ................................................................................... 47 8.6. Living biomass estimation................................................................................................... 50 8.7. Dead organic matter estimation ........................................................................................... 54 8.8. Soil biochemical analyses ................................................................................................... 54 2 8.9. Statistical analyses ............................................................................................................... 56 8.9.1. Soil chemical characteristic: pH and C/N ........................................................................ 56 8.9.2. Living biomass and dead organic matter and Ecosystem C stocks.................................. 56 8.9.3. Soil biochemical indices .................................................................................................. 57 9. RESULTS .................................................................................................................................. 59 9.1. Soil physico-chemical properties ........................................................................................ 59 9.2. SOC and total N concentration ............................................................................................ 61 9.3. Soil organic carbon and nitrogen stocks.............................................................................. 69 9.4. SOC and climate .................................................................................................................. 81 9.5. Living biomass, dead organic matter and ecosystem C stocks ........................................... 84 9.6. Microbial biomass and soil enzyme activity ....................................................................... 91 10. DISCUSSION ....................................................................................................................... 106 10.1. SOC and N concentrations ............................................................................................. 106 10.2. SOC and N stocks .......................................................................................................... 107 10.3. SOC and N stock changes along the chronosequences ................................................. 108 10.4. SOC stock variation in the whole profile ...................................................................... 110 10.5. Living biomass, dead organic matter and Ecosystem C stocks ..................................... 113 10.6. Soil biochemical analyses .............................................................................................. 115 11. CONCLUSIONS AND FUTURE PERSPECTIVES ........................................................... 118 12. ACKNOWLEDGEMENTS .................................................................................................. 121 13. REFERENCES...................................................................................................................... 122 3 1. LIST OF ABBREVIATIONS ABG = aboveground biomass AI = aridity index ARPA = Agenzia regionale per l’ambiente B = biomass BD = bulk density BGB = belowground biomass C = carbon C/N = carbon to nitrogen ratio CEC= cation exchange capacity CLC = CORINE land cover Cmic = microbial biomass carbon Cmic/Nmic = microbial biomass carbon to microbial biomass nitrogen Corg = organic carbon CWD = coarse woody debris DBH = diameter at breast height DCH = diameter at the collar height DEM = digital elevation model DIBAF = Dipartimento per la Innovazione dei sistemi Biologici, Agroalimentari e Forestali E = East EDTA = ethylenediaminetetraacetic acid EEA = European environmental agency ESD = equivalent soil depth ESM = equivalent soil mass F = forest FAO = The Food and Agriculture Organisation FWC = fine woody debris GHG = greenhouse gas GIS = geographic information system GPS = global positioning system 4 H = height H’ = Shannon’s diversity index Hm = mean height IGM = Istituto Geografico Militare INFC = inventario nazionale delle foreste e dei serbatoi forestali di carbonio IPCC = Intergovernmental Panel on Climate Change IUTI = inventario dell’uso delle terre d’Italia L = length LUC = land-use change MAP = mean annual precipitation MAPF = Ministero delle Politiche Agricole e Forestali MAT = mean annual temperature Maxis = major axis MUF = methylumbelliferone N = nitrogen N = North Nmic = microbial biomass nitrogen O = origin, central point P = pasture R/S = root to shoot ratio S = South SA = sampling area SDS = summer dry stress SEIc = Synthetic Enzymatic Index for the carbon cycle enzymes SOC = soil organic carbon SPA = special protection area SUE = substrate