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Dissertation
Matter fluxes in mountain oases of Al Jabal Al Akhdar, Oman
(2012-04-05)
Since 1970 when Sultan Qaboos bin Said Al Said took over power from this father, agriculture in Oman has undergone major transformations as a consequence of rapid population and economic growth. In this process groundwater extraction has dramatically increased to meet domestic and agricultural needs. Recently, the agro-ecosystem of ancient mountain oases of Oman have received greater attention as interest has grown to understand the causes of their often millennia old sustainable productivity.
Particularly little ...
Dissertation
Nutrient cycling and nutrient use efficiency in urban and peri-urban agriculture of Kabul, Afghanistan
(2011-05-31)
Like elsewhere also in Kabul, Afghanistan urban and peri-urban agriculture (UPA) has often been accused of being resource inefficient and unsustainable causing negatives externalities to community health and to the surroundings. These arise from the inappropriate management and use of agricultural inputs, including often pesticides and inter-city wastes containing heavy metal residues and pathogens. To address these concerns, parallel studies with the aims of quantification of carbon (C), nitrogen (N), phosphorus (P) ...
Dissertation
Nutrient and virtual water fluxes of vegetable production and food distribution in two West African cities
(2017-10-04)
Water and food security will be challenged by uncertainties related to changing climatic and socio-economic conditions triggered by urbanization. The present studies aimed at (a) investigating the effects of mineral fertilization and biochar amendment at two water quality and quantity levels on biomass production, plant nutrition, and soil moisture in vegetables with a focus on Tamale, (b) assessing nutrient losses via leaching and gaseous emissions and calculated nutrient balance and use efficiencies in Tamale and ...
Dissertation
Gaseous and leaching losses of carbon and nitrogen in irrigated organic farming of a coastal oasis in Oman
(2011-03-14)
In der Dissertation wurden die Effekte verschiedener C/N-Verhältnisse und verschiedener Verhältnisse von strukturellen zu löslichen Kohlenhydraten (NDF/SC) von Dung, der in bewässerten Gemüsekulturen im Norden Omans appliziert wurde, untersucht. Im auf sandigen Böden durchgeführten Experiment wurden zwei Büffeldungvarianten zum einen mit einem C/N-Verhältnis von 19 und einem NDF/SC-Verhältnis von 17 (ORG1) und zum anderen mit einem C/N-Verhältnis von 25 und einem NDF/SC-Verhältnis von 108 (ORG2) verwendet. Das relevante ...
Dissertation
Effects of tillage intensity on soil C, N, and P pools with different stability
(2013-11-29)
Es ist bekannt, dass die Umsatzdynamik der organischen Substanz von der Bodenbearbeitungsintensität abhängt. Bis jetzt sind nur wenige Daten zum Einfluss der Bearbeitungsintensität und des Zwischenfruchtanbaus auf C-, N-, und P-Dynamik im Ober- (0-5 cm Tiefe) und Unterboden (5-25 cm Tiefe) von Lössböden verfügbar. Hauptziele dieser Arbeit waren die (i) Quantifizierung des Einflusses von verschiedenen langzeitig durchgeführten Bearbeitungssystemen auf labile, intermediäre, und passive C- und N-Pools; (ii) Quantifizierung ...
Dissertation
Effects of grassland renovation on carbon concentrations and aggregate distribution in temperate grassland soils
(2013-12-05)
The effects of continuous tillage on the distribution of soil organic matter (SOM) and aggregates have been well studied for arable soils. However, less is known about the effects of sporadic tillage on SOM and aggregate dynamics in grassland soils. The objectives of the present thesis were (I) to study the longer-term effects of sporadic tillage of grassland on organic carbon (Corg) stocks and the distribution of aggregates and SOM, (II) to investigate the combined effects of sporadic tillage and fertilization on ...
Dissertation
Application of biogas slurries from energy crops to arable soils and their impact on carbon and nitrogen dynamics
(2012-10-19)
The use of renewable primary products as co-substrate or single substrate for biogas production has increased consistently over the last few years. Maize silage is the preferential energy crop used for fermentation due to its high methane (CH4) yield per hectare. Equally, the by-product, namely biogas slurry (BS), is used with increasing frequency as organic fertilizer to return nutrients to the soil and to maintain or increase the organic matter stocks and soil fertility. Studies concerning the application of energy ...
Dissertation
Effects of the application of biochar and organic fertilizers as well as temperature on soil carbon and aggregate dynamics
(2017-11-27)
Soil aggregate formation is an important process for long-term carbon storage in soils. While it has been shown that plant residues exert a positive influence on aggregate formation, the effects of organic fertilizers such as cattle slurry or manure as well as the effects of biochar application to soil are less clear. Furthermore, little is known about the role of increased soil temperatures in aggregate dynamics.
The main objectives of this thesis were to analyse the effects of (i) cattle slurry and manure, (ii) ...
Dissertation
Simulative Risikoanalyse von Biomethanprojekten
(2012-07-30)
Im Zuge der Novellierung der Gasnetzzugangsverordnung sowie des Erneuerbare-Energien-Gesetzes entwickelte sich die Einspeisung von Biomethan in das Erdgasnetz als alternative Investitionsmöglichkeit der Erneuerbare-Energien-Branche. Als problematisch erweist sich dabei die Identifikation und Strukturierung einzelner Risikofaktoren zu einem Risikobereich, sowie die anschließende Quantifizierung dieser Risikofaktoren innerhalb eines Risikoportfolios. Darüber hinaus besteht die Schwierigkeit, diese Risikofaktoren in ...