In the Central Rif in the north of Morocco, forest ecosystems have suffered a very sharp decline in favor of crops. Deforestation followed by cultivation illustrates the important environmental, economic and social roles of forests. The objective of this work is to assess the impact of deforestation on soil properties and erosion in the southern Central Rif. The loss of fertility of cleared soils was assessed using physico-chemical analyses after 2, 8 and 20 years of cultivation. A manual rainfall simulation was used to assess the impact of cultivation on the hydrodynamic behavior of the soil. The results show that the conversion of forests into agricultural areas has multiple consequences on the natural system. The general trend of soil texture elements after cultivation shows a significant increase in sand content, and a decrease in clay and silt content. Soil erodibility measured by USLE-K factor increased 3.5 times in the cultivated soil for 20 yrs. compared to the forest soil. Subsequent tillage of cultivated land increases bulk density and fragments large aggregates into smaller ones. Cultivation for 8 and 20 yr decreased SOM by 41 and 82% respectively. Total Nitrogen decreased by 45%, acidity increased by 0.8 unit after 20 years of cultivation. Conversion of natural forest to agricultural land significantly increases soil erosion. The erosion rate becomes higher in the cultivated the 8 and 20 yr cultivation, with an average of 219.60 ± 19.3 and 989.17 ± 68.4 g m-2 h-1 respectively. This degradation hinders agricultural productivity, leading farmers to abandon the land and seek new plots at the expense of forests to meet their agricultural land needs.
The land in the Aoulai watershed in the Rif mountain area of northern Morocco has been deteriorating continually due to several different forms of erosion. The Aoulai watershed is essentially characterized by the domination of weak resistance of the rocky formations and its sensitiveness to other major internal factors that result in a conspicuous impetus for both mass movements and water erosion.Water erosion is seen as the most damaging phenomenon for nature in northern Morocco because it acts as an obstacle to the natural balances and seems to have greater effect on the slopes, through the influence of both human and natural factors. To assess and examine the erosion phenomenon, we have chosen to conduct a qualitative assessment of water erosion in the Aoulai watershed using the PAP-RAC (Priority Actions Programme/Regional Activity Centre) Guidelines. This is the methodology that is most widely applied and implemented both for determining and identifying the areas at risk of erosion and for supporting projects to reduce the degradation that has become a major threat to hydraulic structures including dams, irrigation pipes and other infrastructure elements, which are damaged by the erosion phenomenon in the Central Rif mountains of northern Morocco.
Apport de la télédétection et du SIG au suivi de la dynamique spatiotemporelle des forêts dans le massif numidien de Jbel RESUMÉLes écosystèmes forestiers du massif numidien de Jbel Outka situé au coeur du Rif Central au nord du Maroc, ont connu, au cours des dernières décennies, de grandes pressions aussi bien naturelles qu'anthropiques conduisant à des changements observables dans le paysage forestier. Néanmoins la nature et l'intensité de ces changements restent peu connues. L'objectif de cette étude est d'évaluer la dynamique du paysage forestier du massif numidien de Jbel d'Outka, et d'en expliquer les causes, en se basant sur une approche GOT, n.º 11 -Revista de Geografia e Ordenamento do Território (junho de 2017) GOT, nr. 11 -Geography and Spatial Planning Journal (June 2017) 172 diachronique repose sur l'intégration et traitement des données multidates et multisources, à l'aide du Système d'Information Géographique (SIG), et des logiciels de la Télédétection spatiale. Les résultats obtenus soulignent une forte régression dans les dynamiques de la forêt.Mots clé : Photographie aérienne ; images satellitaires ; télédétection ; SIG ; milieu forestier ; Jbel Oudka ; Rif Central . RESUMOOs ecossistemas do maciço florestal númido da montanha Outka localizam-se no Rif Central no norte de Marrocos e têm, nas últimas décadas, altas pressões naturais e antropogénicas, levando a alterações observáveis na paisagem florestal. A natureza e a intensidade destas mudanças permanecem pouco conhecidas. O objetivo deste estudo é avaliar a dinâmica da paisagem florestal do maciço Outka da montanha Outka e explicar as suas causas, com base numa abordagem diacrónica, usando a integração e processamento de dados multidate e multi-fonte, usando GPS e software de sensoriamento remoto do espaço. Os resultados obtidos mostram uma forte regressão na dinâmica da floresta.Palavras-chave: Fotografia aérea; Imagens de satélite; Sensoriamento remoto; SIG, floresta de montanha Outka; Montanha de Rif central ABSTRACTThe forest ecosystems of the Numidian massif of Outka mountain are located in the Central Rif in northern Morocco, and have got, over the past decades, high natural and anthropogenic pressures, leading to observable changes in the forest landscape. The nature and the intensity of these changes remain little known. The objective of this study is to assess the dynamics of the forest landscape of the Outka massif of Outka mountain, and explain their causes, based on a diachronic approach, using the integration and processing of multidate and multisource data, Using GPS and Space Remote Sensing software. The results obtained show a strong regression in the dynamics of the forest.
Avaliação e adequação dos currículos de defesa civil dos cursos de formação e aperfeiçoamento do corpo de bombeiros do rio de janeiro com vista à redução do risco de desastres
Les crues et les inondations des agglomérations du Rif méridional méritent une attention particulière dans le processus d’aménagement et d’urbanisme. Le cas du centre Aïn Aïcha est représentatif. En effet, la combinaison des processus physiques et anthropiques influence le système hydrologique de l’Oued Ouerrha à Aïn Aïcha. Le présent travail porte sur la détermination et la cartographie des zones inondables à travers l’application des approches historiques et hydrogéomorphologiques. Elle vise à cartographier les zones qui devront être qualifiées de non ædificandi et, au-delà, à inciter à l’intégration le concept de risque hydrologique dans la planification et la gestion urbaine par les décideurs-aménageurs de la municipalité de Aïn Aïcha.
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