Soil degradation in Central Rif mountains area in northern Morocco: aspects of losses and failure of development programs

In the Rif region in northern Morocco, the degradation of the environment exposes the soil to aggressive erosion agents, especially in the Mediterranean climate in which the evacuation of 2000 tons of soil per km2 per year is a basic average. In these difficult environments is necessary to manage the resource effectively by anticipating the situations of dry and wet years. Several development programs have been carried out in the Rif zone since the 1960s and the problem persists, especially with the arrival of the new agriculture of Cannabis (Drug) in 1995 in the southern part of the study area which is characterized by its precarious environmental balance. This paper aims to examine the aspects of soil degradation and analyze the failure factors of the management programs and projects that have been conducted by several national and international stakeholders including the EU and UN.

The concern for the development of the Rif mountains area, therefore, consists of the balanced management of resources and their development for the creation of reproductive factors, capable of generating sustainable development, likely to retain the population and enhance the labor absorption capacity. It is also a concern to curb the degradation processes that can lead to the desertification of the Rif territory and consequently to absorb the flow of illegal migration to Europe through the Mediterranean Sea and southern Spain.
For this purpose, conceding local opinion is necessary; it is about creating a space for dialogue and consultation with target groups and not imposing a technocratic vision. In this perspective, we find the other connection of the dimension of natural resources and that of development, only effective progress and term of economic, human and social development, in an integrated way on several fronts, can guarantee success in the protection of heritage soils and the balance of territories.

Study area
The study area located in Northern Morocco, This division was designed by several researchers based on different criteria and especially the geological structure (Asebriy, Luca, Bourgois, & Chotin, 1987;Maurer, 1968).
The Central Rif is undoubtedly the region most affected by various types of degradation. These phenomena, which have a considerable impact on the natural environment, are also the major and permanent threat to the environment and society.

Settings and Data
The Central Rif area is very vulnerable to the degradation of natural environments, as it is characterized by a regression of its protective vegetative cover combined with steep slopes, the predominance of friable lithological formations (marl, marl-limestone, and shale) and abundant rainfall.
The Rif mountain chain constituting the southern branch of the Gibraltar arch borders of the Alboran basin (SW of the Western Mediterranean).
The current evolution is complex and results from multiple orogenic processes (burial, exhumation and rifting), in relation to the convergence between the Eurasian and African lithospheric plates (Andrieux, 1971).

Figure 2
Geological structure of Central Rif mountain.

Geological factors
The study area of Central Rif mountain is divided into three big geological categories (Asebriy et al., 1987;Maurer, 1968). In the Northern part, we find the Intrarif zone in direct contact with the flysch zone limited by the Mediterranean Sea, in the southern part there is the Prerif area and in the middle part the Mesorif domain ( Figure 2).

The Intrarif zone consists of three unities,
Ketama unit which appears in the Central Rif (Andrieux, 1971), affected by two schistosity phases and two metamorphism phases. The first phase is of upper Oligocene and lower Miocene, and the second of Upper Miocene (Frizon de Lamotte, Andrieux, & Guézou, 1991). Tangier unit is a little deformed, it is considered as the cover of the Ketama unit, with a stratigraphic series from the Cenomanian to the inferior Miocene. However, it is symbolized by clay marls of the Upper Cretaceous. Loukkos unit is a zone of tectonic scales, which is flushed in the Western Front of the Tangier unit. These facies are of age ranging from the Albo-Aptian to the Eocene (Benyaich, 1991;Lespinasse, 1975).

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Mesorif domain is also named window areas and is characterized by a set of antiforms, whose hearts consist of formations from the lower to middle Miocene overlapped by allochtones and pleated Mesozoic layers (Durand-Delga et al., 1960). This current structure has been interpreted as: • The African Jurassic-Cretaceous passive margin that had undergone a tectonic inversion and would have formed the Miocene Mesorif structure zone (Benzaggagh et al., 2014).  (Benzaggagh et al., 2014).

Prerif domain is dominated by Jurassic and
Cretaceous formations, the same as Mesorif domain, are represented by three different series (Wildi, 1981): • A thick formation of flysch.
• A limestone series, forming the Sofs line.
• An alternating series with dominant of marl formations.
These lithological materials are very friable and have a very high sensitivity to climatic variations.

Climatic aggressiveness: Factor of degradation
The rainfall annual average of the study area varies between 600 mm/year and 1500 mm/year. The variability of the annual rainfall in the study area reached more than 100% between the two stations localized in two extremes borders of the study zone ( Figures 3 and 4).

Annual rainfall/mm
Oudka station Annual rainfall/mm Rainfall average/mm

The gully
The

Sheet erosion
This is the initial stage of soil degradation. This

Degradation of soil resources aspects
The Rif mountain is a place of imbalances. The first imbalance between natural resources and a nt h ro p o g e nic p re s s u re, a s e co n d e co n o mic imbalance, manifested by low production and incomes, and finally a spatial imbalance in comparison with the Atlantic or Mediterranean plains, A natural imbalance which further aggravates the precarious situation of the physical environment.
As the soil is the surface part of the earth is likely to be cultivated due to its physical and chemical properties, clearing activities focus on this horizon.
The first major repercussion of different forms of deforestation is the soil degradation, which is a natural phenomenon inherent in its biological, chemical, physical and hydrological properties that energize our planet. Soil degradation occurs when there is a decline in its productive or functional capacity (Pautrot, 2012    Preparation of materials for erosion on the rural tracks permanently frequented by the herds.

Gully erosion
The Mediterranean climate is renowned for its erosive showers. This condition reinforced by the fragility section areas, according to the degree of slope, the Prerif zone showed that it has a significant influence on the losses of soil by the gully erosion process because it has a high sensitivity to the degradation process.

From gully to Badlands
The formation of runoff on the slopes is common on the semi-arid slopes of the southern part of the Central Rif; It is at the origin of the genesis and the evolution of erosion forms going as far as gully, on the cultivated soils, the fallows, and the paths, with the exceeding of the infiltration capacities, can be at the origin of the runoff and evolved gully settles (Muxart, Cosandey, & Billard, 1990).
Cartographic work was done before the field mission, which showed us that the evolution of gullies  The aerial photograph of Kodiat Belayne gully in the southern Rif mountain area.
Source: Extract from the aerial photo, the mission of 1982

Figure 10
The transformation of the western slope of Koudiat Belayne from gully into badlands in the southern Rif mountain area. • The area has been abandoned for over 10 years, and there is no culture on the western slope of Kodiat Belayne, said the owner of the concerned zone.

Source
• The evolution of the gullies to the Badlands was very rapid compared to the previous years according to the inhabitants near the degraded plot.
• The process of evolution becomes multiple, in the form of mass movement and the digging of gullies, because before the abandonment of the land, the cultivation of the slope had helped to correct the elementary gullies before its evolution into Badlands.

Siltation and solid sediment load
The transition zone between the Rif and Prerif  (Table 1). In the study area, which is characterized by its fragility, the siltation phenomenon is a hydraulic problem that seriously threatens the capacity of Al Wahda dam and/or the satellite dams built to protect its reservoirs downstream (Gartet, El Fengour, Jouad, & García, 2009 (Heusch, 1970).
The quantity of solid sediment load produced varies from one year to another and within the same

Figure 11
Streambank erosion in Amzez wadi at Galaz section in 1953.
Source: Extract from the topographic map, 1953.

Figure 12
Streambank  Table 2). This quantity which exceeds 109.000t/year drains directly into the Al Wahda dam (Heusch, 1970). Table 2 Assessment of solid sediment and its origin in Prerif area.

Diversity of projects and failure of soil management
Among

The national plan for combating desertification
The development will certainly not allow to recover the soil and the totally lost parts. The national plan to combat desertification was prepared in 1986 in accordance with the recommendations of the United Nations Conference on Desertification (UNCOD) in 1977. This plan had two main objectives: • to analyse the achievements and constraints encountered in the implementation of programs.
• to combat desertification and to propose a strategy to combat desertification.
The plan favoured two priority sectors, namely herding and the supply of wood fuel. Thus, actions had been proposed for each of these two sectors (Korachi, 1995). The implementation of the national plan to combat desertification had specific problems related to the absence of an appropriate institution-

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Geografia al framework for the implementation of this plan, since these integrated inter ventions cannot be envisaged, each of the actors has simply continued to conduct its activities as usual without respecting the objectives of the project.

Integrated development projects
The The project involved the planting of olive trees on an area of 8,000 ha, the afforestation of 3,000 ha with Canary pines, the planting of acacias and eucalyptus on 2,000 ha, the fight against gullying on 3,500 ha (Banque, 1978).
This project has also failed to achieve its objectives, despite the financial and human resources available to the authorities to carry it out in the best conditions. The steep slopes planted by olives, in the province of Fez during the period of the project, disappeared completely on some slopes.

The rural development strategy
The rural development strategy, by 2020,

Reforestation plans
The National Plan of Reforestation was elaborat-

Conclusion
The results presented highlight the strong constraint that is exerted on the soil, a constraint which is not only related to the climate, but also to the anthropic action. The vulnerability of the Rif area against degradation is greater, since the 1970s,