**7. Regeneration. A confusion of concepts, different observations and realitiy**

The discussion about regeneration is controversial. There is the position of a definite or long-time degradation, which Miehe et al. [90] explain by a short time of resilience and then a declining to a lower ecological equilibrium. This corroborates the conclusion from the Guidimouni-record as presented above. Hahn and Kusserow [91] and Kusserow [92] report a severe degradation of the Sahel from remote sensing over a long period and also report the algae crusts on silty/clayey sediments as indicators/results of a definite decline of savannas. However, she states that sandy environments will much faster regenerate. Thus, it is necessary to differentiate between the types of environments and also to take the periods of observation into consideration.

### **7.1 The first steps of regeneration**

An example is given by the investigations in the Guidimouni depression (see above). Field work and observations on the lake-cores structure revealed the general regeneration potential of soil surfaces on sandy and clayey sediments. The upper centimetres of the dune tops and their middle slopes expose fine layers of blown sand which are covered and fixed by bacteria/algae films together with their gelly formations (biofilms). These biocrusts are the first stages of reorganisation and they represent a general phenomenon in its bimodal feature: deposition of a mineral layer which is afterwards settled and covered by bacteria and algae. This represents a general phenomenon of soil surface organisation: that of film like OPS/ PSO (pellicular surface organisation) in the sense of Pomel [92], see also [93–95]. Thus, it is obvious that even under intensive exploitation, the tendency of regeneration of vegetation and soil still exists.

The general mode of sandy crust formation is explained by **Figure 18** (above). The upper series represent the regular repetition of coarse and fine sand layers mainly fixed by cohesion as it is the case for sand layers in the desert described above for the achabs. Anyhow, the normal development is that of biocrusts as represented in the middle series. The ever present spores of cyanobacteria and algae germ rapidly and create a biofilm of jellies and thus stabilise surfaces. The algae belong to the *Nostoc*- and *Lyngbya*-realm with a nodular and chain-formed appearence [91]. When covered by another sand layer the bacteria/algae will rapidly form another cover. Even though these crusts are fragile and may crack easily, they enable a further succession of grasses and herbs as a next step. Seeds may be blown in cracks and they may germ and exploit the nutrition reserves of the biocrusts. Finally, these crusts may be seen as functional types representing the early stages of soil development [96, 97].

On silty/clayey stones or sediments, the situation is different as **Figure 15** (below) may show. The surface of these fine grained rocks or shallow soils are often covered by thick cyanobacteria/algae layers which may reach to several mm thickness (cf. [91]). They are coherent and impede an implantation of seeds. When covered by dust or fine sand, they easily reform. Finally, their smooth surface is water repellent and for longer periods, they may be an obstacle to a colonisation of grasses or herbs – not to speak about trees.

### **Figure 18.**

*The first steps of regeneration and biocrusts in sandy (above) and clayey (below) sediments (from [69], modified).*

**83**

**Figure 19.**

*Vegetation Dynamics. Natural versus Cultural and the Regeneration Potential. The Example…*

In contrast to them, the rapid regeneration mode of the cyanobacteria/algae crusts on sandy soils is successfully exploited in the dune rehabilitation of Northern China [98, 99]. The crusts are collected, crushed and afterwards sprayed over loose sand surfaces or dunes, which gives a good example of working with natural succession.

If one regards the philosophy, performance and success of the various projects which are active or planned in the Sahel, we have to differentiate between the large scale technical ones and those, which are adapted to the conditions of the population.

Among the large-scale projects, we have the extended dune fixation by fencing and tree plantation [102] or the transcontinental 'Great Green Wall' [17, 18] still based on the idea of an extending desert (see **Figures 8, 19, 20**). The second type is the creation of large natural reserves or national parks in the Sahara and the Sahel. They are initiated or proposed for auto-regeneration of vegetation and wildlife – following mostly the WWF-philosophy see [14, 16]. Very often their aim is to protect emblematic animals, which are supposed to act as key stone organisms (see for both **Figure 1**). The opposite is the creation of pasture-rotation systems to exploit the limited resources but also guarantee their regeneration. Finally, they are the counterparts of the old shifting/fallow cultivation, which by now in the Sahel is only rarely carried

The northern part of the Gourma region (Mali) from the Niger-bow to the mountains of Hombori (17°-15°N) is a perfect example of Middle and Northern

*The pasture-rotation system of Gourma/Mali during the 1970s and 1980s and the long time observation project* 

*of regeneration up to 2017. Graphs on regeneration without scale [8, 100]. Drawing Schulz.*

*7.2.1 Gourma – guide – great green wall. The limits of regeneration*

out. Several examples will illustrate these projects.

*7.2.2 The rotation pasture system 'Gourma'*

*DOI: http://dx.doi.org/10.5772/intechopen.87030*

**7.2 Regeneration in the landscape scale**

*Vegetation Dynamics. Natural versus Cultural and the Regeneration Potential. The Example… DOI: http://dx.doi.org/10.5772/intechopen.87030*

In contrast to them, the rapid regeneration mode of the cyanobacteria/algae crusts on sandy soils is successfully exploited in the dune rehabilitation of Northern China [98, 99]. The crusts are collected, crushed and afterwards sprayed over loose sand surfaces or dunes, which gives a good example of working with natural succession.

### **7.2 Regeneration in the landscape scale**

*Plant Communities and Their Environment*

**7.1 The first steps of regeneration**

tion of vegetation and soil still exists.

grasses or herbs – not to speak about trees.

over a long period and also report the algae crusts on silty/clayey sediments as indicators/results of a definite decline of savannas. However, she states that sandy environments will much faster regenerate. Thus, it is necessary to differentiate between the types of environments and also to take the periods of observation into consideration.

An example is given by the investigations in the Guidimouni depression (see above). Field work and observations on the lake-cores structure revealed the general regeneration potential of soil surfaces on sandy and clayey sediments. The upper centimetres of the dune tops and their middle slopes expose fine layers of blown sand which are covered and fixed by bacteria/algae films together with their gelly formations (biofilms). These biocrusts are the first stages of reorganisation and they represent a general phenomenon in its bimodal feature: deposition of a mineral layer which is afterwards settled and covered by bacteria and algae. This represents a general phenomenon of soil surface organisation: that of film like OPS/ PSO (pellicular surface organisation) in the sense of Pomel [92], see also [93–95]. Thus, it is obvious that even under intensive exploitation, the tendency of regenera-

The general mode of sandy crust formation is explained by **Figure 18** (above). The upper series represent the regular repetition of coarse and fine sand layers mainly fixed by cohesion as it is the case for sand layers in the desert described above for the achabs. Anyhow, the normal development is that of biocrusts as represented in the middle series. The ever present spores of cyanobacteria and algae germ rapidly and create a biofilm of jellies and thus stabilise surfaces. The algae belong to the *Nostoc*- and *Lyngbya*-realm with a nodular and chain-formed appearence [91]. When covered by another sand layer the bacteria/algae will rapidly form another cover. Even though these crusts are fragile and may crack easily, they enable a further succession of grasses and herbs as a next step. Seeds may be blown in cracks and they may germ and exploit the nutrition reserves of the biocrusts. Finally, these crusts may be seen as functional types representing the early stages of soil development [96, 97]. On silty/clayey stones or sediments, the situation is different as **Figure 15** (below) may show. The surface of these fine grained rocks or shallow soils are often covered by thick cyanobacteria/algae layers which may reach to several mm thickness (cf. [91]). They are coherent and impede an implantation of seeds. When covered by dust or fine sand, they easily reform. Finally, their smooth surface is water repellent and for longer periods, they may be an obstacle to a colonisation of

*The first steps of regeneration and biocrusts in sandy (above) and clayey (below) sediments (from [69],* 

**82**

**Figure 18.**

*modified).*

If one regards the philosophy, performance and success of the various projects which are active or planned in the Sahel, we have to differentiate between the large scale technical ones and those, which are adapted to the conditions of the population.

### *7.2.1 Gourma – guide – great green wall. The limits of regeneration*

Among the large-scale projects, we have the extended dune fixation by fencing and tree plantation [102] or the transcontinental 'Great Green Wall' [17, 18] still based on the idea of an extending desert (see **Figures 8, 19, 20**). The second type is the creation of large natural reserves or national parks in the Sahara and the Sahel. They are initiated or proposed for auto-regeneration of vegetation and wildlife – following mostly the WWF-philosophy see [14, 16]. Very often their aim is to protect emblematic animals, which are supposed to act as key stone organisms (see for both **Figure 1**).

The opposite is the creation of pasture-rotation systems to exploit the limited resources but also guarantee their regeneration. Finally, they are the counterparts of the old shifting/fallow cultivation, which by now in the Sahel is only rarely carried out. Several examples will illustrate these projects.

### *7.2.2 The rotation pasture system 'Gourma'*

The northern part of the Gourma region (Mali) from the Niger-bow to the mountains of Hombori (17°-15°N) is a perfect example of Middle and Northern

### **Figure 19.**

*The pasture-rotation system of Gourma/Mali during the 1970s and 1980s and the long time observation project of regeneration up to 2017. Graphs on regeneration without scale [8, 100]. Drawing Schulz.*

### **Figure 20.**

*The pasture rotation project 'Guide' in the Central Air Mts. [43, 101]. (A) The Wadi vegetation in the innerpart of the ring structure. (B) The regeneration of trees and shrubs after the second year of closure. See also the dense herb cover under the* Acacia*-umbrellas. Drawing Schulz.*

Sahel-savannas. They range from a Combretaceae-savanna of tiger bush in the South to the *Acacia-Commiphora*-*Balanites*-savannas of the North. East of Tombouctou there even existed a real *Acacia*-forest, which was formerlyx exploited for the steam boat lines to Bamako [103–105]. The savannas represented for long time a rich pasture, which could not be exploited [100] as only a few wells or water points existed. Thus, human impact was restricted to the river-banks and the northern savannas, where the cattle keepers had constructed a series of hafirs (rain fed pools). The other regions were the oxbows of river Niger in the West and the agriculture areas near the mountains in the South. Instead there was an intensive elephant pasture creatred by the greatest herds of West Africa [106]. Probably, these savannas may be regarded as the gullivers of elephant impact [107], giving a good example for the reports of the voyagers of the nineteenth century (see above). Only a few wells were constructed in the first half of the twentieth century. But the aureoles of overgrazing developed rapidly around them. With the drought of the 1960s, the Sahel started to degrade. However, in the Gourma, it went differently. Together with the local cattle keepers and authorities, the geologist R. Reichelt from CILSS developed a rotation system of new wells and pasture. It was based on the opening and closing of wells depending on the state of the pastures around, which were regularly controlled. When degradation started, the wells were closed and the cattle keepers were obliged to proceed to other wells and pastures. This system worked from the end of the 1960s on and revented the desertification phenomena, which had hit the regions around. But in 1984 – at the peak of the drought, a great number of cattle keepers from then North of Niger River invaded the region. They were not familiar with the rotation system and did not respect it. After severe quarrels of the herders, the rotation system collapsed.

Anyway, for long years, it represented a sustainable pasture system, which saved the Gourma region from the desertification as it occured in the regions around. It is one of the curiosities in science that these experiences were completely forgotten and were not taken into account in the whole discussion on desertification and regeneration management.

From about 1984, a long time observation project (see **Figure 19B**) was installed in the same region. Its goal was to follow the degradation-regeneration processes under various conditions and exploitations [8]. It was a multidisciplinary project mainly based on field observation and remote sensing. It could evaluate the regeneration chances of the different savanna systems and it well demonstrated that regeneration started early on sandy substrates both for herbs and trees, but on clayey sediments degradation continued even after protection. Here, the regeneration started only after a long period, which corroborated the experiences from other regions (see above). But the general insecurity of the regions forced the colleagues to abandon the project in 2014 [4].

**85**

end to this success.

*7.2.4 Think big! Bridging Sahara and West Africa*

*7.2.4.1 National parks or natural reserves*

*Vegetation Dynamics. Natural versus Cultural and the Regeneration Potential. The Example…*

The extreme degradation of herb and tree pastures in the Air Mts. on the one hand and the octroyance of the Reserve Naturelle de l'Air et Ténéré (see **Figure 6**, [101, 108]) with the exclusion of the herders from traditional pasture areas on the other initiated the planning of a new regeneration concept together with the local authorities of the Timia village in the central Air Mts. [108]. **Figure 8** explains the general situation. It shows the two granite ring structures of Agalak and Aroyan and the upper part of the Wadi Anou Mekkerene, one of the greatest of the Air Mts. And it also depicts the altitudinal change in the Air Mts. from the mountain savannas to the middle stretches of the wadi Anou Mekkerene heading

Within 4 or 5 years, a rotation system, which functioned on the closure of pastures for several years, aimed to assure the regeneration of grasses, herbs and trees. At the same time, a sustainable exploitation system of the pastures should impede a new degeneration by overgrazing or other forms of over-exploitation. The first of these closures was the mountain pasture 'Guide' southeast of Timia (see **Figures 6, 8**). It is situated in the Aroyan-granite ring structure, which could easily be closed in 1986 for 4 years. This area showed the typical transitions from the contracted desert vegetation to the mountain savannas of the Sahelian type. The soil cover of vegetation did not exceed 10% but could rise to 70% under the umbrella of Acacias. The first years showed an enormous growth rate of trees as well for the seedlings-saplings as for branches and twigs −30 cm – for *Acacia* and *Maerua*. Apparently, trees could profit from the good rainy season and from the reduced concurrence of herbs, which suffered from the preceding drought. In 1990, a first two-days-opening was organised for fruit collection and grass cutting. The enclosure was mapped for vegetation, a floristic inventory was organised and also some demilunes/half moon sand accumulations and stone lines were constructed in order to collect rain water [101, 109]. Within 4 years, the development of tree and grass pastures was as astonishing high, and also people from other villages had planned to initiate comparable systems. After the controlled opening in 1991, a second pasture was closed for regeneration. For the long run, the village council discussed the models of an interdiction of pastures but with controlled collection of grass and fruits or controlled pasture. In the mountain savannas, the protection and controlled collection of medicinal herbs was an attractive point too. Anyway, a permanent following up of vegetation development was planned for the future. The Guide-project evidenced the chances of local and accepted regeneration initiatives and it could have been a model for other regions. Unfortunately, as for the Gourma project, the rebellion and the successive insecurity put a premature

The creation of extended reserve areas or national parks have been generated by the ideas of an auto-regeneration through excluding further human exploitation or

For the Sahara, the three National parks or natural reserves of Air-Ténéré (see **Figures 1, 6**), Termit-Tin- Toumma and Wadi Rime-Wadi Achmed in Niger and Chad should protect huge ecosystems and also support regeneration of vegetation and wildlife (see **Figure 1**). These are the greatest protection areas in the Sahara and in Africa as a whole and were supposed bridge the areas of endangered key

through the protection of emblematic animals as key stone organisms.

*DOI: http://dx.doi.org/10.5772/intechopen.87030*

to the West.

*7.2.3 The pasture rotation project 'Guide' in the central Air Mts*

*Vegetation Dynamics. Natural versus Cultural and the Regeneration Potential. The Example… DOI: http://dx.doi.org/10.5772/intechopen.87030*

### *7.2.3 The pasture rotation project 'Guide' in the central Air Mts*

*Plant Communities and Their Environment*

**Figure 20.**

Sahel-savannas. They range from a Combretaceae-savanna of tiger bush in the South to the *Acacia-Commiphora*-*Balanites*-savannas of the North. East of Tombouctou there even existed a real *Acacia*-forest, which was formerlyx exploited for the steam boat lines to Bamako [103–105]. The savannas represented for long time a rich pasture, which could not be exploited [100] as only a few wells or water points existed. Thus, human impact was restricted to the river-banks and the northern savannas, where the cattle keepers had constructed a series of hafirs (rain fed pools). The other regions were the oxbows of river Niger in the West and the agriculture areas near the mountains in the South. Instead there was an intensive elephant pasture creatred by the greatest herds of West Africa [106]. Probably, these savannas may be regarded as the gullivers of elephant impact [107], giving a good example for the reports of the voyagers of the nineteenth century (see above). Only a few wells were constructed in the first half of the twentieth century. But the aureoles of overgrazing developed rapidly around them. With the drought of the 1960s, the Sahel started to degrade. However, in the Gourma, it went differently. Together with the local cattle keepers and authorities, the geologist R. Reichelt from CILSS developed a rotation system of new wells and pasture. It was based on the opening and closing of wells depending on the state of the pastures around, which were regularly controlled. When degradation started, the wells were closed and the cattle keepers were obliged to proceed to other wells and pastures. This system worked from the end of the 1960s on and revented the desertification phenomena, which had hit the regions around. But in 1984 – at the peak of the drought, a great number of cattle keepers from then North of Niger River invaded the region. They were not familiar with the rotation system and did not

*The pasture rotation project 'Guide' in the Central Air Mts. [43, 101]. (A) The Wadi vegetation in the innerpart of the ring structure. (B) The regeneration of trees and shrubs after the second year of closure. See* 

*also the dense herb cover under the* Acacia*-umbrellas. Drawing Schulz.*

respect it. After severe quarrels of the herders, the rotation system collapsed.

Anyway, for long years, it represented a sustainable pasture system, which saved the Gourma region from the desertification as it occured in the regions around. It is one of the curiosities in science that these experiences were completely forgotten and were not taken into account in the whole discussion on desertification and

From about 1984, a long time observation project (see **Figure 19B**) was installed in the same region. Its goal was to follow the degradation-regeneration processes under various conditions and exploitations [8]. It was a multidisciplinary project mainly based on field observation and remote sensing. It could evaluate the regeneration chances of the different savanna systems and it well demonstrated that regeneration started early on sandy substrates both for herbs and trees, but on clayey sediments degradation continued even after protection. Here, the regeneration started only after a long period, which corroborated the experiences from other regions (see above). But the general insecurity of the regions forced the colleagues

**84**

regeneration management.

to abandon the project in 2014 [4].

The extreme degradation of herb and tree pastures in the Air Mts. on the one hand and the octroyance of the Reserve Naturelle de l'Air et Ténéré (see **Figure 6**, [101, 108]) with the exclusion of the herders from traditional pasture areas on the other initiated the planning of a new regeneration concept together with the local authorities of the Timia village in the central Air Mts. [108]. **Figure 8** explains the general situation. It shows the two granite ring structures of Agalak and Aroyan and the upper part of the Wadi Anou Mekkerene, one of the greatest of the Air Mts. And it also depicts the altitudinal change in the Air Mts. from the mountain savannas to the middle stretches of the wadi Anou Mekkerene heading to the West.

Within 4 or 5 years, a rotation system, which functioned on the closure of pastures for several years, aimed to assure the regeneration of grasses, herbs and trees. At the same time, a sustainable exploitation system of the pastures should impede a new degeneration by overgrazing or other forms of over-exploitation. The first of these closures was the mountain pasture 'Guide' southeast of Timia (see **Figures 6, 8**). It is situated in the Aroyan-granite ring structure, which could easily be closed in 1986 for 4 years. This area showed the typical transitions from the contracted desert vegetation to the mountain savannas of the Sahelian type. The soil cover of vegetation did not exceed 10% but could rise to 70% under the umbrella of Acacias. The first years showed an enormous growth rate of trees as well for the seedlings-saplings as for branches and twigs −30 cm – for *Acacia* and *Maerua*. Apparently, trees could profit from the good rainy season and from the reduced concurrence of herbs, which suffered from the preceding drought. In 1990, a first two-days-opening was organised for fruit collection and grass cutting. The enclosure was mapped for vegetation, a floristic inventory was organised and also some demilunes/half moon sand accumulations and stone lines were constructed in order to collect rain water [101, 109]. Within 4 years, the development of tree and grass pastures was as astonishing high, and also people from other villages had planned to initiate comparable systems. After the controlled opening in 1991, a second pasture was closed for regeneration. For the long run, the village council discussed the models of an interdiction of pastures but with controlled collection of grass and fruits or controlled pasture. In the mountain savannas, the protection and controlled collection of medicinal herbs was an attractive point too. Anyway, a permanent following up of vegetation development was planned for the future. The Guide-project evidenced the chances of local and accepted regeneration initiatives and it could have been a model for other regions. Unfortunately, as for the Gourma project, the rebellion and the successive insecurity put a premature end to this success.

### *7.2.4 Think big! Bridging Sahara and West Africa*

### *7.2.4.1 National parks or natural reserves*

The creation of extended reserve areas or national parks have been generated by the ideas of an auto-regeneration through excluding further human exploitation or through the protection of emblematic animals as key stone organisms.

For the Sahara, the three National parks or natural reserves of Air-Ténéré (see **Figures 1, 6**), Termit-Tin- Toumma and Wadi Rime-Wadi Achmed in Niger and Chad should protect huge ecosystems and also support regeneration of vegetation and wildlife (see **Figure 1**). These are the greatest protection areas in the Sahara and in Africa as a whole and were supposed bridge the areas of endangered key

stone animals [15, 16, 110]. Moreover, there was already a survey on the chances to establish a system of monetary exploitation of ecosystem services [111]. However, these initiatives often disturbed the traditional pasture systems, and due to the insufficient involvement of the local populations, it led to various problems and frictions. Anyhow, the sense of these protections and reserve areas was not really communicated to and accepted by the concerned populations. Thus in the 1990s, with the beginning of the rebellions in Mali, Niger and Chad, these projects were no longer accepted by and the state could no longer maintain them. Today, most of them gained a status of 'being endangered' or 'in suspense' [112]. At present, the natural reserve Air-Ténéré continues in a certain cooperation with the local population in order to manage resources [113].

## *7.2.4.2 The 'Great Green Wall'*

This is the continental flagship of the protection-regeneration projects and follows still the philosophy of expanding ecosystems and the combat against them (see **Figure 1**). The project was created by the African Union in 2007 [17, 114] as a 7800 km belt from Senegal to Djibouti. Fifteen kilometres wide, it should work as protection against wind and erosion. Afforestation should provide nutrients to the soil and also ameliorate pasture by foliage and shadow too. Finally, the tradition of agroforestry (parks see above) was taken as a model (see also [115]). Research on amelioration of soil and plant fertility is an important part such as investigation on the symbiosis of bacteria/fungi and acacias. Anyway, as for the other smaller or greater projects, this initiative came to an intermediate (?) end caused by the general insecurity in the concerned areas. But the research in the various institutes of the partner states continues in the hope to reactivate and readjust this flagship. However, it already serves for the governmental propaganda. The presidency of Niger claimed to have plated millions of trees in order to reduce soil erosion and to fix dunes [116].

### **7.3 'Small scale' as a chance!?**

Several projects and activities concentrate on the regeneration and amelioration of degraded soils in order to restore the soil cover and to assure food production [117, 118]. They are mostly organised on personal or village level and so they are participative. These activities have to be seen on the background of a general extensification of agriculture, parallel to the intensification, e.g., irrigation cultures at favoured places [119]. Most Sahelian farmers are still subsistence-oriented. This means that they mainly crop to nurture their families rather than to produce market products. The steadily increasing population with growth rates of about 3%

### **Figure 21.**

*Regeneration and food security measurements in Niger. (A) Tassa /Zai-cultivation on the Ader-plateau, Central Niger. (B) Reduced weeding in S-Niger. (C) Intensive irrigation for vegetable production at Niamey, Niger. Drawing Schulz.*

**87**

*Vegetation Dynamics. Natural versus Cultural and the Regeneration Potential. The Example…*

per annum leads either to an expansion of cropped surfaces to marginal land or – where the population density is already high – to decreasing cropland per family.

The 'tassa' or 'zai' culture (**Figure 21A**) is an old cultivation system of degraded soils [120]. It is based on dug in holes, 10–40 cm in diameter and 10–25 cm in deep in a distance of about 1 m. These holes can store rain and run off and thus support the regeneration of spontaneous vegetation. They may be filled with leaves or

Experiments showed the possibilities of 640 kg–800 kg/ha yields of millet. The dug in holes must be renovated each year. As the financial component is quite low and as it is based on personal or village activity, 'Tassa' is the most appropriate and

In the Haoussa region around Maradi in Niger, average farm size has reached meanwhile about 2 ha. For the simple reason of survival, intensification of cropping

However, a number of obstacles exist that hinder the application of innovations. Among these are traditions, low educational level, low investment capacity and the need for risk management. The latter aspect means that farmers are risk averse and are not – in contrast to the normal economical theory– yield or income maximisers.

So the question is: how does innovation needs to be alike to be acceptable for farmers. The answer is manyfold: the innovation needs to be simple, affordable, relying on local resources, risk reducing, functioning under multiple weather scenarios and it cannot contradict local customs. There are not many innovations that fulfil these criteria, in particular if we want to address the 'regreening' of the Sahel. We can approach the 'regreening' from two angles. One is the re-establishment of ligneous vegetation, and the other is increasing the crop biomass production. At the first glance, these are contradictory objectives. Is this really so? In order to answer this question, we will discuss different options in

Heavy convective storms are a regular phenomenon in the Sahel. They lead to erosion on open surfaces at the beginning of the rainy season and homogenisation of soil surface properties through redistribution of particulate matter [121, 122]. The saltating sand grains damage the young seedlings and can lead to crop loss at an early vegetative state. Therefore, it is reasonable to think of windbreaks as a solution to the problem. A lot of research has been done in this respect [118, 123]. However, we hardly see any adoption of this technology by farmers. What are the problems? It begins with legal problems. Planting a tree means to express a claim on property. This is delicate in societies were the land is distributed according to local traditions. Second, planting trees in a hedgerow means an investment that is hardly affordable for a single farmer. A third argument for rejection is the workload for making the trees survive after planting and for pruning in order to reduce competition with the neighbouring crop later. And the

*7.3.2 The amelioration of crop planting by preservation or planting of trees*

*DOI: http://dx.doi.org/10.5772/intechopen.87030*

*7.3.1 The restoration on heavily degraded soils*

compost in order to attract the termites.

widely accepted cultivation system.

First of all, the family members need to survive.

*7.3.2.1 Windbreaks (or agro-forestry in a more general sense)*

is mandatory.

the following.

Several examples illustrate these activities (see **Figure 21**).

*Vegetation Dynamics. Natural versus Cultural and the Regeneration Potential. The Example… DOI: http://dx.doi.org/10.5772/intechopen.87030*

per annum leads either to an expansion of cropped surfaces to marginal land or – where the population density is already high – to decreasing cropland per family. Several examples illustrate these activities (see **Figure 21**).

### *7.3.1 The restoration on heavily degraded soils*

*Plant Communities and Their Environment*

tion in order to manage resources [113].

*7.2.4.2 The 'Great Green Wall'*

fix dunes [116].

**7.3 'Small scale' as a chance!?**

stone animals [15, 16, 110]. Moreover, there was already a survey on the chances to establish a system of monetary exploitation of ecosystem services [111]. However, these initiatives often disturbed the traditional pasture systems, and due to the insufficient involvement of the local populations, it led to various problems and frictions. Anyhow, the sense of these protections and reserve areas was not really communicated to and accepted by the concerned populations. Thus in the 1990s, with the beginning of the rebellions in Mali, Niger and Chad, these projects were no longer accepted by and the state could no longer maintain them. Today, most of them gained a status of 'being endangered' or 'in suspense' [112]. At present, the natural reserve Air-Ténéré continues in a certain cooperation with the local popula-

This is the continental flagship of the protection-regeneration projects and follows still the philosophy of expanding ecosystems and the combat against them (see **Figure 1**). The project was created by the African Union in 2007 [17, 114] as a 7800 km belt from Senegal to Djibouti. Fifteen kilometres wide, it should work as protection against wind and erosion. Afforestation should provide nutrients to the soil and also ameliorate pasture by foliage and shadow too. Finally, the tradition of agroforestry (parks see above) was taken as a model (see also [115]). Research on amelioration of soil and plant fertility is an important part such as investigation on the symbiosis of bacteria/fungi and acacias. Anyway, as for the other smaller or greater projects, this initiative came to an intermediate (?) end caused by the general insecurity in the concerned areas. But the research in the various institutes of the partner states continues in the hope to reactivate and readjust this flagship. However, it already serves for the governmental propaganda. The presidency of Niger claimed to have plated millions of trees in order to reduce soil erosion and to

Several projects and activities concentrate on the regeneration and amelioration of degraded soils in order to restore the soil cover and to assure food production [117, 118]. They are mostly organised on personal or village level and so they are participative. These activities have to be seen on the background of a general extensification of agriculture, parallel to the intensification, e.g., irrigation cultures at favoured places [119]. Most Sahelian farmers are still subsistence-oriented. This means that they mainly crop to nurture their families rather than to produce market products. The steadily increasing population with growth rates of about 3%

*Regeneration and food security measurements in Niger. (A) Tassa /Zai-cultivation on the Ader-plateau, Central Niger. (B) Reduced weeding in S-Niger. (C) Intensive irrigation for vegetable production at Niamey,* 

**86**

**Figure 21.**

*Niger. Drawing Schulz.*

The 'tassa' or 'zai' culture (**Figure 21A**) is an old cultivation system of degraded soils [120]. It is based on dug in holes, 10–40 cm in diameter and 10–25 cm in deep in a distance of about 1 m. These holes can store rain and run off and thus support the regeneration of spontaneous vegetation. They may be filled with leaves or compost in order to attract the termites.

Experiments showed the possibilities of 640 kg–800 kg/ha yields of millet. The dug in holes must be renovated each year. As the financial component is quite low and as it is based on personal or village activity, 'Tassa' is the most appropriate and widely accepted cultivation system.

### *7.3.2 The amelioration of crop planting by preservation or planting of trees*

In the Haoussa region around Maradi in Niger, average farm size has reached meanwhile about 2 ha. For the simple reason of survival, intensification of cropping is mandatory.

However, a number of obstacles exist that hinder the application of innovations. Among these are traditions, low educational level, low investment capacity and the need for risk management. The latter aspect means that farmers are risk averse and are not – in contrast to the normal economical theory– yield or income maximisers. First of all, the family members need to survive.

So the question is: how does innovation needs to be alike to be acceptable for farmers. The answer is manyfold: the innovation needs to be simple, affordable, relying on local resources, risk reducing, functioning under multiple weather scenarios and it cannot contradict local customs. There are not many innovations that fulfil these criteria, in particular if we want to address the 'regreening' of the Sahel. We can approach the 'regreening' from two angles. One is the re-establishment of ligneous vegetation, and the other is increasing the crop biomass production. At the first glance, these are contradictory objectives. Is this really so? In order to answer this question, we will discuss different options in the following.

### *7.3.2.1 Windbreaks (or agro-forestry in a more general sense)*

Heavy convective storms are a regular phenomenon in the Sahel. They lead to erosion on open surfaces at the beginning of the rainy season and homogenisation of soil surface properties through redistribution of particulate matter [121, 122]. The saltating sand grains damage the young seedlings and can lead to crop loss at an early vegetative state. Therefore, it is reasonable to think of windbreaks as a solution to the problem. A lot of research has been done in this respect [118, 123]. However, we hardly see any adoption of this technology by farmers. What are the problems? It begins with legal problems. Planting a tree means to express a claim on property. This is delicate in societies were the land is distributed according to local traditions. Second, planting trees in a hedgerow means an investment that is hardly affordable for a single farmer. A third argument for rejection is the workload for making the trees survive after planting and for pruning in order to reduce competition with the neighbouring crop later. And the competition for land, water, light and nutrients is the fourth argument to set this technology aside. In conclusion, hedgerows are a typical innovation typical for scientists and based on on-station results, thus neglecting the constraints of the rural populations.

Are there more simple and adoptable solutions? One is, i.e., called farmermanaged natural regeneration [124]. It uses the regeneration of ligneous species by re-sprouting from rootstocks. Already Wezel et al. [125] could show in the 1990s that the minimum yield of pearl millet increased with the number of small bushes in the field. This is achieved through the reduction of the negative wind erosion effects and the increase of the organic matter stock that is the major provider of the major limiting nutrient phosphorus. As side effect, fire wood is provided. In contrast to hedgerow planting, with this technology, the only input to be provided is low: i.e., only pruning. The disadvantage is that it is only possible in nonmechanised agriculture. And, the woody species composition is hardly foreseeable. Studies in the Maradi area in Niger have shown that in densely populated areas, all still existing woody species are under use and that their distribution is depending on the distance to settlements (**Figure 22**).

Close to settlements, old *Faidherbia albida* trees dominated are protected, since they deliver high quality animal fodder and do not compete during the rainy season with the crop due to the leaf cover developing in the off-season. Farther away from the settlements, *Piliostigma reticulata* and *Combretum glutinosum* dominate are mainly used as fire wood resources. Also crops differ with distance to the settlements, cash crops like cowpea grown more closely to the settlements on the more fertile sites. Reasons are protection against theft and higher expected

### **Figure 22.**

*A survey on tree vegetation in the* Faidherbia*-park zones around a village in southern Niger. Dominance (>40% counts) of woody species >1 m crown diameter (white boxes) and number of woody species detected and their average height (number/heigth m) on transects with increasing distance to the village Warzou, central southern Niger (Jigawa, Jampali, Guezami-guezami and Gueza being local soil names indicating increasing clay content in this order). Survey and assembly by Herrmann 2017.*

**89**

*Vegetation Dynamics. Natural versus Cultural and the Regeneration Potential. The Example…*

yields due to nutrient concentration closer to the settlements. Another variable explaining crop diversity is soil conditions, *Sorghum* preferentially being cropped

If one wants to reduce wind and water erosion effects on cropping, the simple technique of partial weeding is an option (**Figure 21B**). Under Sahelian conditions, sowing and weeding are the most time-consuming agricultural actions. Labour shortage during these periods limits agricultural performance, since crop surfaces fall out of the scheme. Partial weeding, i.e., stripwise weeding in the sowing lines or circular weeding around the sowing pockets, reduces the workload for the first weeding by about 50%. The herbs and grasses left standing then act as a semi-natural erosion barrier. In addition, this vegetation component stores nutrients that were otherwise leached. In this way, the weeds can be used as an intermittent nutrient reservoir that can be managed, and nutrients are provided to the crop when needed

The Sahel is the genetic center for the major staple crop pearl millet that is mainly planted on the sandy sites. Many different land races exist that have been developed by local communities by mass selection over generations. These local communities have a quite determined idea about what a variety must provide with regard to pest and drought resistance, taste, and yield, just to name a few aspects. Independent development of so-called 'improved varieties' has repeatedly failed, simply due to the fact that breeders were not aware of the mandatory properties for different communities, and they did breeding on-station under conditions that are not comparable to the farm environment. Therefore, the future agricultural research needs to be more participatory and include the farmers perspective already at the state of objective definition. Then, higher biomass yielding varieties can be developed.

Under the Sahelian conditions, dry sowing before the rainy season is an option if fields are too far from the settlements, if the rainy season starts very later or for women, when they are not able to sow at the time due to the obligation to help her husbands on their fields first. However, dry sowing imposes the risk of seed loss through predation or early droughts. In order to assure a timely establishment of the pearl millet crop, the seedball technology was developed [126]. It uses local resources like sand, loam, seeds and a little bit of fertiliser (NPK or wood ash) to form small balls of about 2 cm diameter. Seedballs have shown to increase biomass and yield by about 30% under all kinds of conditions in sandy low fertility soils. The only constraint is the labour required for seedball production. However, this can be accomplished during the dry season when opportunity costs are low.

The sandy soils of the northern Sahel are characterised by a low chemical fertility, phosphoruns and nitrogen being the main limiting nutrients for cereal crops. The soils are so poor that even the smallest amounts of nutrient addition

*7.3.2.2 Partial weeding as wind erosion barrier and intermediate nutrient stock*

*DOI: http://dx.doi.org/10.5772/intechopen.87030*

on the more loamy sites.

by a timely second weeding.

*7.3.3 Varieties*

*7.3.4 Seedballs*

*7.3.5 Microdosing*

*Vegetation Dynamics. Natural versus Cultural and the Regeneration Potential. The Example… DOI: http://dx.doi.org/10.5772/intechopen.87030*

yields due to nutrient concentration closer to the settlements. Another variable explaining crop diversity is soil conditions, *Sorghum* preferentially being cropped on the more loamy sites.

## *7.3.2.2 Partial weeding as wind erosion barrier and intermediate nutrient stock*

If one wants to reduce wind and water erosion effects on cropping, the simple technique of partial weeding is an option (**Figure 21B**). Under Sahelian conditions, sowing and weeding are the most time-consuming agricultural actions. Labour shortage during these periods limits agricultural performance, since crop surfaces fall out of the scheme. Partial weeding, i.e., stripwise weeding in the sowing lines or circular weeding around the sowing pockets, reduces the workload for the first weeding by about 50%. The herbs and grasses left standing then act as a semi-natural erosion barrier. In addition, this vegetation component stores nutrients that were otherwise leached. In this way, the weeds can be used as an intermittent nutrient reservoir that can be managed, and nutrients are provided to the crop when needed by a timely second weeding.

## *7.3.3 Varieties*

*Plant Communities and Their Environment*

on the distance to settlements (**Figure 22**).

rural populations.

competition for land, water, light and nutrients is the fourth argument to set this technology aside. In conclusion, hedgerows are a typical innovation typical for scientists and based on on-station results, thus neglecting the constraints of the

Are there more simple and adoptable solutions? One is, i.e., called farmermanaged natural regeneration [124]. It uses the regeneration of ligneous species by re-sprouting from rootstocks. Already Wezel et al. [125] could show in the 1990s that the minimum yield of pearl millet increased with the number of small bushes in the field. This is achieved through the reduction of the negative wind erosion effects and the increase of the organic matter stock that is the major provider of the major limiting nutrient phosphorus. As side effect, fire wood is provided. In contrast to hedgerow planting, with this technology, the only input to be provided

is low: i.e., only pruning. The disadvantage is that it is only possible in non-

mechanised agriculture. And, the woody species composition is hardly foreseeable. Studies in the Maradi area in Niger have shown that in densely populated areas, all still existing woody species are under use and that their distribution is depending

Close to settlements, old *Faidherbia albida* trees dominated are protected, since they deliver high quality animal fodder and do not compete during the rainy season with the crop due to the leaf cover developing in the off-season. Farther away from the settlements, *Piliostigma reticulata* and *Combretum glutinosum* dominate are mainly used as fire wood resources. Also crops differ with distance to the settlements, cash crops like cowpea grown more closely to the settlements on the more fertile sites. Reasons are protection against theft and higher expected

*A survey on tree vegetation in the* Faidherbia*-park zones around a village in southern Niger. Dominance (>40% counts) of woody species >1 m crown diameter (white boxes) and number of woody species detected and their average height (number/heigth m) on transects with increasing distance to the village Warzou, central southern Niger (Jigawa, Jampali, Guezami-guezami and Gueza being local soil names indicating increasing* 

*clay content in this order). Survey and assembly by Herrmann 2017.*

**88**

**Figure 22.**

The Sahel is the genetic center for the major staple crop pearl millet that is mainly planted on the sandy sites. Many different land races exist that have been developed by local communities by mass selection over generations. These local communities have a quite determined idea about what a variety must provide with regard to pest and drought resistance, taste, and yield, just to name a few aspects. Independent development of so-called 'improved varieties' has repeatedly failed, simply due to the fact that breeders were not aware of the mandatory properties for different communities, and they did breeding on-station under conditions that are not comparable to the farm environment. Therefore, the future agricultural research needs to be more participatory and include the farmers perspective already at the state of objective definition. Then, higher biomass yielding varieties can be developed.

### *7.3.4 Seedballs*

Under the Sahelian conditions, dry sowing before the rainy season is an option if fields are too far from the settlements, if the rainy season starts very later or for women, when they are not able to sow at the time due to the obligation to help her husbands on their fields first. However, dry sowing imposes the risk of seed loss through predation or early droughts. In order to assure a timely establishment of the pearl millet crop, the seedball technology was developed [126]. It uses local resources like sand, loam, seeds and a little bit of fertiliser (NPK or wood ash) to form small balls of about 2 cm diameter. Seedballs have shown to increase biomass and yield by about 30% under all kinds of conditions in sandy low fertility soils. The only constraint is the labour required for seedball production. However, this can be accomplished during the dry season when opportunity costs are low.

### *7.3.5 Microdosing*

The sandy soils of the northern Sahel are characterised by a low chemical fertility, phosphoruns and nitrogen being the main limiting nutrients for cereal crops. The soils are so poor that even the smallest amounts of nutrient addition

can boost the yield. Based on this knowledge, micro-dosing as fertiliser strategy has been developed [127, 128]. Micro-dosing means a placed fertilisation (in contrast to broadcast application) into the sowing pocket at sowing or early in the season, where the nutrients are needed most. Only 2 kg of phosporus are able to double the yield on the poorest sites. Micro-dosing at sowing supports the early establishment of the plant. Once the crop is established and crop loss ha not to be expected, further fertilisation can be done without the risk of investment loss.

However, for the poorest farmers in remote areas, even market access to fertiliser is limited. They can rely on wood ash as local fertiliser, since cooking is done with firewood. Wood ash provides soluble phosphours, potassium, calcium and other micro-nutrients. It can be considered as a complex fertiliser, since it stems from plants. Consequently, it provides most nutrients needed by plants. two grams of wood ash placed into the sowing pocket but at little distance to pearl millet seeds has proven to be effective in increasing yield on poor sites. For legumes, this local fertiliser is applied shortly before flowering.

### *7.3.6 OGA*

OGA is fermented human urine that is used as liquid fertiliser. It is an autochthonous innovation developed by the farmer organisation Fuma Gaskiya in the Maradi area of Niger taking Asian practices as example. It mainly contains nitrogen and potassium as fertilising compounds and has shown to consistently increase pearl millet biomass and grain yield. It is a resource that is locally available for free. It is placed application makes it efficient in annihilating the nitrogen constraint of crop production. Combined with wood ash application (as source for soluble phosphorus), two local resources can be used to fight the notorious soil deficiency with respect to these nutrients. In addition, it is reported by farmers that the smell of OGA is effective to chase off harmful insects.

### *7.3.7 Biological insect control*

The head miner became a major during the Sahelian droughts of the 1970s. Pesticide control is out of reach for subsistence farmers. In consequence, a biological control mechanism using the parasitoid wasp *Habrobracon hebetor* was developed. The parasitoid can potentially be produced locally. However, there is still no agro-enterprise that has taken up this innovation. Perhaps, production is too sophisticated and potential price levels or too high for application by subsistence farmers.

### *7.3.8 The diversification or the counter-season production*

Food security shall be enlarged by intensified and irrigated vegetable production. It constitutes by now a widely accepted activity, wherever the bases are given (**Figure 21C**). It ranges from the vegetable and fruit production in the vicinity of towns or to intensive onion production for export [83, 129]. It can be run on as personal activity or as a collective one.

Thus, these small-scale projects proved chances on the personal of village level to earn its own living and to build sustainable base for villages. They fulfil the demand for participativity and local decision on the projects. Moreover, they are less endangered by the overall insecurity and they may develop their systems by own experiences, and guaranteeing thus a long performance, independently from external pressures.

**91**

**Figure 23.**

*modified.*

*Vegetation Dynamics. Natural versus Cultural and the Regeneration Potential. The Example…*

After all there is an augmentation in the plant cover. It is evident too in the southern Sahara and the northern Sahel as well as in the Park region of the southern Sahel, from where it was taken by [130, 131] as a sign of a principal 'regreening'. But there is still degradation of ecosystems parallel to that recovery in some regions [7, 12].

Finally, the green future of the Sahelian areas needs a landscape approach where the different stakeholders jointly act in a way it takes into account that the multiple angles of natural and socio-economic environment. Short-term action by decision makers who want to see short-term results and who are driven by the dogma of novelty – in particular in science – will not lead to a sound outcome. In contrast, the basics need to be understood, more participatory action is needed, and long-term development concepts need to be supported. Agriculture has to and is able to support the landscape productivity and thus 'greening'. No sophisticated approaches are needed, but the insight that subsistence oriented agriculture needs innovations that are simple, affordable and based on local resources. In a long-term, a re-integration of crop and livestock production is inevitable to partly close the nutrient cycle. The decade long experience of our colleagues from university of Abdou Moumouni university of Niamey [132, 133] came to the general conclusion on regeneration possibilities of degraded landscapes (see **Figure 21**). Damage and degradation of *Acacia-albida*-parks and Combretaceae-savannas in the Southeast of Niger (stages 1 and 2) diminished the resources for the local population in such a dimension that an intervention was necessary. The classical stonewalls on the slopes alone provoked runnels climbing up the slope and aggravated the situation (stage 3). Thus, it was necessary to intervene at all points and for a long period in order to stop further linear erosion and to allow the auto-regeneration of vegetation and soil (stage 4). Especially on silty-clayey grounds, it will take time to collect sufficient organic material on the surface to allow an implantation of grasses and herbs as further stages of succession. Mulching, however, turned out to be successful to attract ants of termites to transport

*Experiences with the regeneration of an overexploited* Faidherbia*-park Southwest of Niamey [69, 132],* 

*DOI: http://dx.doi.org/10.5772/intechopen.87030*

**7.5 In the long run – future prospects**

**7.4 Finally, the 'Greening'**

*Vegetation Dynamics. Natural versus Cultural and the Regeneration Potential. The Example… DOI: http://dx.doi.org/10.5772/intechopen.87030*
