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Now showing items 81-90 of 251
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
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
Effects of activated charcoal and quebracho tannins on the turnover of goat manure in irrigated organic agriculture of the subtropics
(2015-04-15)
Agriculture in semi-arid and arid regions is constantly gaining importance for the security of the nutrition of humankind because of the rapid population growth. At the same time, especially these regions are more and more endangered by soil degradation, limited resources and extreme climatic conditions. One way to retain soil fertility under these conditions in the long run is to increase the soil organic matter. Thus, a two-year field experiment was conducted to test the efficiency of activated charcoal and quebracho ...
Dissertation
Effects of phosphorus and water stress on shoot and root growth and on mycorrhization of different pearl millet (Pennisetum glaucum (L.) R. Br.) varieties from West Africa
(2015-03-13)
This research work aimed at investigating the physiological mechanisms of tolerance of pearl millet to low soil Phosphorus availability and drought under the Sahelian conditions.
Dissertation
Effects of irrigation water quality on soil properties and crops in urban gardens of Ouagadougou, Burkina Faso
(2018-02-15)
Urban food production is an important supplier of fresh produce in the rapidly growing West African cities. In year-round vegetable production of the semi-arid tropics, low quality water is often use for irrigation. This results in health risks for producers and consumers, and causes environmental pollution, followed by soil contamination and crop yield reduction. In the presented PhD thesis quality and effects of irrigation water in urban vegetable gardens of Ouagadougou, Burkina Faso, were examined. The aim of these ...
Dissertation
Changes of traditional farming systems and their effects on land degradation and socio-economic conditions in the Inle Lake region, Myanmar
(2016-04-22)
At many locations in Myanmar, ongoing changes in land use have negative environmental impacts and threaten natural ecosystems at local, regional and national scales. In particular, the watershed area of Inle Lake in eastern Myanmar is strongly affected by the environmental effects of deforestation and soil erosion caused by agricultural intensification and expansion of agricultural land, which are exacerbated by the increasing population pressure and the growing number of tourists. This thesis, therefore, focuses on ...
Aufsatz
Drainage, salt leaching and physico-chemical properties of irrigated man-made terrace soils in a mountain oasis of northern Oman
(2005)
Little is known about the sustainability of irrigated oasis agriculture in northern Oman. The objective of this study therefore was to examine which factors allowed agricultural productivity to be apparently maintained during the two millenia of a mountain oasis’ existence. Soil moisture and physico-chemical properties were measured in a typical flood-irrigated field sown to alfalfa (Medicago sativa L.). Particle size, organic (C_org) and inorganic carbon content, pH and electrical conductivity (EC)of the soil profile ...
Aufsatz
Precision mapping
(2000)
The nondestructive determination of plant total dry matter (TDM) in the field is greatly preferable to the harvest of entire plots in areas such as the Sahel where small differences in soil properties may cause large differences in crop growth within short distances. Existing equipment to nondestructively determine TDM is either expensive or unreliable. Therefore, two radiometers for measuring reflected red and near-infrared light were designed, mounted on a single wheeled hand cart and attached to a differential ...