Faculty of Agricultural Sciences
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Faculty of Agricultural Sciences Institute of Agricultural Sciences in the Tropics (Hans-Ruthenberg-Institute) University of Hohenheim Agroecology in the Tropics and Subtropics Prof. Dr. Joachim Sauerborn Mitigate Habitat Degradation in the Semiarid Brazil – Potential and Limitation of the Endemic Tree Spondias tuberosa Arruda Dissertation Submitted in fulfillment of the requirements for the degree doctor scientiarum agrarium (Dr. sc. agr.) to the Faculty of Agricultural Sciences by Jan Heiko Mertens Stuttgart, Germany, 2017 Date of defense of the doctoral thesis: Wednesday 8th November 2017 Dean of the faculty of Agricultural Sciences: Prof. Dr. Ralf T. Vögele Examination Committee: Chairman of the committee: Prof. Dr. Stefan Böttinger Supervisor and reviewer: Prof. Dr. Joachim Sauerborn Co-reviewer: Prof. Dr. Christof Engels Third Examiner: Prof. Dr. Reiner Doluschitz Acho muita malvadeza Tirar raiz de umbuzeiro Pra fazer doce de corte E se trocar por dinheiro E prejudicar a planta No período do sequeir¥ from Marialvo Barreto: “Se Umbuzeiro falasse...” ¥ Freely translated: I think it is very evil – cutting the roots of the Umbuzeiro – just to make sweets – convert them to money – harming the plant – in the drought period. Table of Contents Table of Contents Summary.....................................................................................................................................V Zusammenfassung...................................................................................................................VIII Resumo....................................................................................................................................XII Notes on Publications..............................................................................................................XVI List of Abbreviations.............................................................................................................XVII 1.General Introduction.................................................................................................................1 1.1 Caatinga, home of a seasonally dry tropical forest............................................................1 1.2 Land-use in the Caatinga and its impacts on the biome....................................................4 1.3 Problem statement............................................................................................................8 1.4 Aim and objectives.........................................................................................................10 1.5 Study area.......................................................................................................................11 2.Umbuzeiro (Spondias tuberosa): A Systematic Review...........................................................13 2.1 Introduction....................................................................................................................14 2.2 Phenology, abundance, and reproductive biology...........................................................15 2.3 Physiology......................................................................................................................18 2.4 Population genetics.........................................................................................................21 2.5 Management practices....................................................................................................22 2.6 Economic aspects...........................................................................................................25 2.7 Spondias tuberosa, a medical plant.................................................................................28 2.8 Conclusion.....................................................................................................................29 3.Spondias tuberosa Arruda (Anacardiaceae), a Threatened Tree of the Brazilian Caatinga?....32 3.1 Introduction....................................................................................................................33 3.2 State of research.............................................................................................................35 3.3 Factors reported constraining the natural regeneration of Spondias tuberosa..................36 Pests............................................................................................................................37 Restricted seed dispersal.............................................................................................37 Climate change...........................................................................................................38 Browsing.....................................................................................................................39 3.4 Potential factors which may constrain the natural regeneration of Spondias tuberosa.....40 I Table of Contents Wood extraction.........................................................................................................41 Fruit picking...............................................................................................................41 3.5 Conclusion.....................................................................................................................41 4.Effect of Biochar, Clay Substrate, and Manure Application on Water Availability and Tree- Seedling Performance in a sandy Soil........................................................................................45 4.1 Introduction....................................................................................................................46 4.2 Material and methods.....................................................................................................47 Site description...........................................................................................................47 Experimental design...................................................................................................47 Plant material..............................................................................................................48 Soil analyses................................................................................................................48 Soil conditioners.........................................................................................................49 Soil physical analyses..................................................................................................50 Plant analyses..............................................................................................................51 Statistics......................................................................................................................52 4.3 Results............................................................................................................................52 Bulk density (ρb), total porosity(Φ) and air capacity (AC)..........................................52 Water content at field capacity (θfc), water content at permanent wilting point (θpwp) and available water capacity (θa)..................................................................................53 Infiltration...................................................................................................................56 Soil water content.......................................................................................................56 Soil carbon..................................................................................................................60 Seedling growth..........................................................................................................60 Seedling survival.........................................................................................................60 4.4 Discussion......................................................................................................................61 Soil physical parameters.............................................................................................61 Plant parameters.........................................................................................................63 4.5 Conclusion.....................................................................................................................64 5.Comparison of Soil Amendments for Reforestation with a Native Multipurpose Tree Under Semiarid Climate: Root and Root Tuber Response of Spondias tuberosa..................................65 5.1 Introduction....................................................................................................................67 II Table of Contents 5.2 Material and methods.....................................................................................................69 Site description...........................................................................................................69 Experimental design...................................................................................................70 Quantification of fine roots.........................................................................................72 Description of coarse root plus root tuber architecture...............................................73 Shoot harvest and seedling viability............................................................................74 Soil physical parameters.............................................................................................74