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Dissertation
Agricultural practices and horizontal nutrient balances in urban gardens and the alternative use of urban agricultural land in Khartoum, Sudan
(2012-02-16)
The surge in the urban population evident in most developing countries is a worldwide phenomenon, and often the result of drought, conflicts, poverty and the lack of education opportunities. In parallel with the growth of the cities is the growing need for food which leads to the burgeoning expansion of urban and peri-urban agriculture (UPA). In this context, urban agriculture (UA) contributes significantly to supplying local markets with both vegetable and animal produce. As an income generating activity, UA also ...
Dissertation
Water use efficiency and management of agro-pastoral landuse systems in the Mongolian-Chinese Altay
(2017-02-08)
The use of organic fertilizers is an important approach to maintain soil fertility of irrigated agricultural land under the semi-arid climate conditions of Oman. However, gaseous emissions of carbon and nutrients from soil and organic fertilizers are a major challenge. Activated charcoal and tannins have the potential to reduce gaseous losses of carbon and nitrogen. Therefore, gaseous emissions of carbon dioxide (CO2), ammonia (NH3) and nitrous oxide (N2O) were measured by a photo-acoustic infrared multi-gas monitor. ...
Dissertation
Evaluation of Pathological Risks Associated with Use of Leguminous Cover crop and Living mulch species
(2017-11-15)
In the past 10 to 15 years, there has been a tendency in Europe to switch from cereal based cropping systems, with winter and summer fallow, to cropping systems which combine greater crop diversity with maximum soil cover. Increasing the opportunities of including legumes into crop rotations to be grown as cover crops, intercropped or under-sown with cereals can provide multiple beneficial services to agro-ecosystems. A major concern is however, that many of the leguminous species of interest share important soil-borne ...
Dissertation
Matter flows and balances in urban vegetable gardens of Bobo Dioulasso, Burkina Faso (West Africa)
(kassel university press, 2012-07-30)
Many efforts are undertaken for sustaining urban agriculture in African cities. This study therefore investigated nutrient management practices in urban vegetable gardens of Bobo Dioulasso, Burkina Faso (West Africa). Nitrogen (N), phosphorus (P), potassium (K), and carbon (C) fluxes were quantified and nutrient balances calculated for three gardens representing the typical commercial gardening + field crops and livestock system (cGCL) and three gardens representing the commercial gardening + semi-commercial field ...
Dissertation
Integrated soil fertility management in eastern and western Africa: The role of knowledge and innovation systems, its adoption and impact
(2017-01-31)
The rise in population growth, as well as nutrient mining, has contributed to low agricultural productivity in Sub-Saharan Africa (SSA). A plethora of technologies to boost agricultural production have been developed but the dissemination of these agricultural innovations and subsequent uptake by smallholder farmers has remained a challenge. Scientists and philanthropists have adopted the Integrated Soil Fertility Management (ISFM) paradigm as a means to promote sustainable intensification of African farming systems. ...
Dissertation
Nitrogen use efficiency and optimization of nitrogen fertilizer application for stable yields and high quality of cereals grown in conservation agriculture
(2017-01-23)
In most agroecosystems, nitrogen (N) is the most important nutrient limiting plant growth. One management strategy that affects N cycling and N use efficiency (NUE) is conservation agriculture (CA), an agricultural system based on a combination of minimum tillage, crop residue retention and crop rotation. Available results on the optimization of NUE in CA are inconsistent and studies that cover all three components of CA are scarce. Presently, CA is promoted in the Yaqui Valley in Northern Mexico, the country´s major ...
Dissertation
Genetic variation of and environmental effects on inducibility of resistance in tomatoes (Solanum lycopersicum L.) to Phytophthora infestans (Mont) de Bary
(2010-12-02)
Many plant strengtheners are promoted for their supposed effects on nutrient uptake and/or resistance induction (IR). In addition, many organic fertilizers are supposed to enhance plant health and several studies have shown that tomatoes grown organically are more resistant to late blight, caused by Phytophthora infestans to tomatoes grown conventionally. Much is known about the mechanisms underlying IR. In contrast, there is no systematic knowledge about genetic variation for IR. Therefore, the following questions ...
Dissertation
Effects of fertilizer type and rate on partitioning of soil organic matter into pools of different stability
(2010-05-26)
Type and rate of fertilizers influence the level of soil organic carbon (Corg) and total nitrogen (Nt) markedly, but the effect on C and N partitioning into different pools is open to question. The objectives of the present work were to:
(i) quantify the impact of fertilizer type and rate on labile, intermediate and passive C and N pools by using a combination of biological, chemical and mathematical methods;
(ii) explain previously reported differences in the soil organic matter (SOM) levels between soils receiving ...
Dissertation
Effects of tillage on processes of organic matter sequestration
(2010-06-28)
To increase the organic matter (OM) content in the soil is one main goal in arable soil management. The adoption of tillage systems with reduced tillage depth and/or frequency (reduced tillage) or of no-tillage was found to increase the concentration of soil OM compared to conventional tillage (CT; ploughing to 20-30 cm). However, the underlying processes are not yet clear and are discussed contradictorily. So far, few investigations were conducted on tillage systems with a shallow tillage depth (minimum tillage = ...