Land suitability evaluation to optimize land management of small-scale farms in the Gerado catchment, North-Eastern Ethiopia

Biophysical and socio-economic constrains, and sub-optimal utilization of soil and water resources have resulted in progressive reduction of land productivity in Ethiopia. This study investigated the suitability of land mapping units of the Gerado catchment for subsistence rainfed cultivation of wheat (Triticum aestivum L.), maize (Zea mays L.) and teff (Eragrostis tef Zucc.). A land resource survey was conducted and it identified nine different land mapping units (LMU). The FAO maximum limitation method was used to assess LMU and determine land suitability subclasses. The study indicated that soil erosion, soil wetness, soil fertility status, and soil workability were the main limiting factors affecting land quality within the catchment. We suggest that drainage using traditional ditches may be a cost-effective method to reduce the incidence of waterlogging conditions. Long-term fertility management requires the implementation of suitable fertilization programmes that consider the use of organic materials such as manure and compost. Such programmes need to account for nutrient budgets over the entire crop rotation to maximize use efficiency and minimize environmental losses. Soil erosion may be mitigated through stone terracing, soil bunding and by adopting a more conservative approach to agriculture, that is, by matching land use with land capability based on the correct assessment of land suitability. Implementation of the proposed approach to optimizing land management in the Gerado catchment will deliver a range of socio-economic and agri-environmental benefits to the local communities

Population growth and other factors affecting land-use and land-cover changes in north-eastern Wollega, Ethiopia

This study investigated the influence of population growth on land-use/land-cover changes observed in north-eastern Wollega, Ethiopia between 1972 and 2005. A knowledge-base that will support sound and informed decision-making on sustainable resource management is provided. The changes in land-use/land-cover observed in this region are linked to rainfall and availability of arable land. These two factors combined have encouraged the migration of farmers from relatively less productive areas of the north and centre of the country. To quantify impacts, the study used a combination of land-use/land-cover detection techniques based on time series image processing, assessment of population dynamics and linear regression models. Results indicated that since the 1970s, cropland and settlement areas expanded at the expense of land formerly occupied by forest, shrub and grassland. The regression analyses showed that such changes were associated (P<0.05) with population growth, which averaged 3% per year. The decline in areas occupied by grassland was not correlated with population growth but rather with changes in land-use. Other factors that significantly influenced land-use/land-cover changes were: farming system, government policies and land tenure system, and lack of technology choices. Maintaining the necessary resource-base is a requirement to ensure the long-term sustainability of the region. Therefore, appropriate land management policies need to be developed and implemented at the national level, however, measures should have regional relevance. Additional measures such as promotion of policies that support the process of sustainable intensification of Ethiopian agriculture coupled with effective extension effort, and greater diversification of the source of income for the rural communities are also suggested

Technologies d’Application des Pesticides par Injection Direct: Etat de l’Art et Possibilité d’Adoption dans les Pays en Développement

Direct Injection Spraying (DIS) consists on injecting chemical and carrier water online. This technology is technically appreciated as a clean method to reduce operator exposure and leftover chemical mixtures. However, DIS performance depends on lag transport and system reactivity to speed up chemical concentration process change, on chemical mixing quality in the spray line, and on cleaning of circuit processing concentrated chemical. This review gives an overview on development of direct injection spraying as a variable rate technology that has been impacted evolution of the precision agriculture during the three last decades. DIS performances are related to reduction of lag transport which has been studied by many researchers using chemical injection close to spraying boom or at the nozzle body. The DIS reactivity has been improved with reference to performance of mixing and cleaning process. From the technical and economical point of view, adoption of DIS technology is kept reserved to developed countries. An effort could be done to promote the technology adoption in developing countries by taking into account possibility of simplifying this DIS e technology and proposing cost effective DIS designs to be affordable and adoptable in the context of small scale farming.Un système de pulvérisation par injection directe (DIS) consiste à injecter en ligne un produit chimique liquide dans de l’eau jouant le rôle d’un liquide porteur. Cette technologie est techniquement appréciée comme méthode propre pour réduire l'exposition de l'opérateur et les restes des bouillies chimiques. Cependant, les performances des systèmes DIS dépendent du délai de transport des concentrations chimiques, de la réactivité du système permettant d’accélérer le processus de changement des concentrations chimiques et de la conception du système de pulvérisation pour assurer un bon mélange de produit chimique en cours de transport sur la ligne hydraulique de pulvérisation. Le nettoyage du circuit hydraulique de dosage et d’injection des produits chimiques concentrés constitue aussi un critère de jugement de performance et de chance d’adoption des systèmes DIS. La réduction de délai du transport a été étudiée par de nombreux chercheurs en utilisant l'injection du concentré chimique à proximité de la rampe de pulvérisation ou au niveau des porte-buses, mais une telle amélioration ne peut être réalisée sans affecter la performance du processus de mélange et le nettoyage du circuit hydraulique. De point de vue technico-économique, la diffusion de la technologie DIS reste encore réservée aux pays développés. Tout tentative visant la promotion de l'adoption des technologies DIS dans les pays en développement ne pourrait se faire sans simplification des systèmes DIS proposés. Il est possible de proposer une technologie DIS à prix abordable, potentiellement adaptée pour le contexte des petites et moyennes exploitations agricoles