Plant-animal material flows and production efficiencies in urban and peri-urban agriculture in a West African city

Funding: German Research Foundation
Project duration: 2006-2009
Editing: Martina Predotov, Diogo Rodrigue V. Cao

Against the background of the strong growth of large African cities and the associated supply and environmental problems, urban and peri-urban agriculture (UPA), which is developing particularly strongly there, is attracting increasing scientific interest. In contrast to the subsistence-oriented land use systems prevailing on extremely nutrient-poor, erosion-prone soils of the hinterland, UPA is characterized by high input intensities. However, there are currently hardly any fundamental studies on productivity, material turnover and environmentally relevant externalities of UPA, which combines animal and crop production systems. In this research project, material flows in the UPA will be measured in selected households in the Nigerian capital Niamey and their key parameters will be modeled. These investigations will then be used to examine proposals for increasing resource efficiency. To this end, in a first step, the horizontal inputs and losses of nitrogen (N), phosphorus (P) and potassium (K) at the soil-plant-animal interfaces will be recorded over the course of the year on 20 sample farms selected according to their degree of integration of animal husbandry and arable farming. On some of these farms, atmospheric emissions (denitrification and ammonia losses) will be determined at representative points in time using a photoacoustic trace glass analyzer and leaching-related nutrient losses (N, P and K) will be measured by installing Si-carbide suction plates. In a second step, the influence of targeted improvement measures in materials management (use of straw and rock phosphate bedding in stationary animal housing, controlled composting of animal manure) on atmospheric N losses and manure quality will be examined. In the third step, the influence of different intensity and integration levels of UPA on the recorded material flows in the soil-plant-animal-environment continuum will be mapped using a bio-physical model.