My dissertation had as its starting point the intention of two Tanzanian farmer's initiatives and their German partners to disseminate sustainable cooking and sanitation technologies to smallholder households in Karagwe District, in northwest Tanzania (TZ). These locally developed and adapted technologies include improved cook stoves, such as microgasifiers, and a system combining biogas digesters and burners for cooking, as well as urine-diverting dry toilets and thermal sterilization/pasteurization for ecological sanitation (EcoSan). Currently, the most common combination of technologies used for cooking and sanitation in Karagwe smallholdings is a three-stone fire and pit latrine. Switching to the new alternatives could potentially lead to (i) optimized resource consumption, (ii) lower environmental emissions, and (iii) a higher availability of domestic residues for soil fertility management. The latter include biogas slurry from anaerobic digestion, powdery biochar from microgasifiers, and sanitized human excreta from EcoSan facilities. These residues are `locally available resources' that can be used for on-farm material cycling. Using TZ as an example and local initiatives as case studies, I have examined the triple nexus of `energy-sanitation-agriculture' with an interdispicplinary multi-method approach. Empirically and analytically, my results shed light on agronomic potentials of an intersectional resource management for circular economies and on values of material cycling in smallholder farming systems as well as on weak points in the system, from both ecological and socio-economic perspectives. As one example, I demonstrated that all the treatments analyzed could enhance crop productivity up to 400 % in a short-term experiment on the local Andosol. [Please see longer Abstract in my thesis for the summary of more results.] Ultimately, I conclude that a particularly promising way of implementing an intersectional resource management around the nexus energy-sanitation-agriculture is the combination of using microgasifiers for cooking and implementing EcoSan, in addition to the combined recycling of biochar and sanitized excreta in `CaSa-compost'. This approach can achieve multiple goals including: (i) increase access to fertilizers, (ii) decrease nutrient depletion and acidification of soils, (iii) increase food production and farm income, (iv) reduce resource consumption, and (v) reduce environmental impacts, like global warming or eutrophication. For many smallholder farmers in Sub-Saharan Africa, this practical approach thus represents a viable exit strategy from the vicious circle of soil acidity and P-scarcity leading to insufficient production of food crops, which in turn leads to insufficient production of residual matter for soil fertility management and improvement.


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    Title :

    Valuing wastes.
    eine integrierte Systemanalyse der Bioenergienutzung, ökologischen Sanitärversorgung und des Bodenfruchtbarkeitsmanagements in kleinbäuerlicher Landwirtschaft in Karagwe, Tansania


    Subtitle :

    an integrated system analysis of bioenergy, ecological sanitation, and soil fertility management in smallholder farming in Karagwe, Tanzania


    Additional title:

    Abfälle wertschätzen


    Contributors:

    Publication date :

    2019



    Type of media :

    Miscellaneous


    Type of material :

    Electronic Resource


    Language :

    English



    Classification :

    DDC:    629 / 577




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