This study was carried out in the Bonkoukou potential irrigable lands of the South West Niger Republic. Bonkoukou (14˚00'37"N and 3˚12'42"E) is located about 145 km north-east of Niamey, the capital of Niger (Figure 1). It is the county town of the rural municipality of Imanan, in the department of Filingué (Tillabery Region; Figure 1). The Imanan Commune covers a total area of 506.06 km² [10]. It counts 46,734 people (2016) living in 53 administrative villages and seven administrative districts [5]. Imanan is located in the South Western Sahel compartment, with a rainfall index ranging between 300 and 600 mm [6] [9]. The highest temperatures are recorded in April and May (45˚C) and the lowest in February (18˚C) [11].

The landscape of Imanan is marked by two dominant reliefs: the fossil valley and the plateaus [12]. Within these two sets, a mosaic of agroecological facies emerges which present quite contrasting characteristics and sometimes profound disparities in the suitability of use of the environments [11]. More characteristic is the centering of the rural commune on a section of the valley of Bosso

Dallol which narrows on five kilometers wide before widening again towards the south [10]. The Bosso Dallol is an ancient dried-up stream that descends from the southern foothills of the Aïr massif [12]. Thus, with its main tributary (the Azagaret), the Dallol Bosso extends to the south the hydrographic network of the Azawak up to the confluence of the Niger River [12] (Figure 1).

The bottom of the Dallol Bosso valley is covered with sand forming soft undulations between which there are sometimes lowlands with heavy alluvial soils rich in silt [11]. It is these alluvial lands that, during the rainy season (wintering), more or less extensive ponds are formed. The plains are carpeted with sandy loam soils. These are areas for rainfed crops and extensive breeding in the dry season. They are very exploited and in places present dune complexes and glacis. In fact, this concerns land not only in full saturation with the marked decrease in fallow which leads to a scarcity of possibilities for extension, but also and above all the effects of the phenomenon of degradation. The glacis is covered with ferruginous soils that are not very cultivated and not very fertile.

On either side of the valley, the plateaus form a double line of cliffs with a drop of 35 to 40 meters, respectively to the east and to the west. At the level of the cliffs and slopes, the plateaus reveal several layers of clayey sandstone colored in pink, yellow or purple. These clayey sandstones are surmounted by a ferralitic cuirass of 1.50 to 2.50 m which bears witness to the so-called “intermediate” erosion surface [12]. To the east, the same sandstone plateau is also covered with cuirass. Overall, the plateaus have been cut by a network of small silted valleys with a discontinuous succession of lowlands which, more clayey and one to two kilometers wide, end in the Dallol [10].

The free-table aquifers, sometimes confused with the “water table” of Continental terminal 3 (Ct³), are contained in Quaternary fluvial alluvium and are some 20 to 30 m thick [13]. Thus, water levels are generally located at an average depth of 14 m from the ground [6] (Figure 2). Groundwater reserves are estimated at around 5.163 billion m³ [10]. The increase in ions of chemical elements (e.g. Na⁺, K⁺ and Cl⁻) in the superficial zone is due to the evaporation and leaching of salts accumulated in the unsaturated zone during the dry season [14]. According to the [10] the geographical coverage rate for drinking water in the rural commune of Imanan was 71.04% in 2018, while the theoretical access rate was 49.43% for a rate of breakdown is 12.68%. The piezometric fluctuations of free water tables are caused by the relatively faster infiltration of surface water during the rainy season (June to September) [15]. The waters of these aquifers are soft and slightly mineralized, but are very sensitive to pollution and/or bacteriological factors. As surface water, the rural commune of Imanan has five permanent ponds and 23 semi-permanent ponds. The Eggrou area has the most semi-permanent ponds. These ponds are mainly used for watering animals, for making bricks and for construction. Today, it is around some of them that fish farming and market gardening are developing [10]. The vegetation of the rural municipality of Imanan consists mainly of wooded and shrub steppes which differ according to the units of land and the type of soil it occupies [14].

The documentary approach is one of the three methods used to better frame the study area, along with exploratory studies and direct observation. Bibliographic research has been a privileged tool for gathering metadata on the data disseminated. It is in various documentations (journals, theses, technical reports and administrative documents) related to the subject that it is agreed to be interested, and more specifically in the Community Development Plan of Imanan (CDPI) [10].

The exploration phase took place from September 1^st to 9^th, 2020. It consisted of visiting the various individual and collective market gardening sites in the rural commune of Imanan. Subsequently, several actors in the field were approached. These include, among others, the notables of Bonkoukou, the technical and administrative services, the heads of the market gardening group, the staff of FCMN Niyya. At this stage of exploration, the goal is to gather information about their activity and create comparative data. The profile of the vegetable production system is established by considering the sites visited and the value provided by the findings and observations of each of these components. At this level, sampling was carried out on five (5) collective sites (Balley Koira, Iguefane, Eggrou, Kochilan Tuareg and Femmes INRAN) of the 17 collective sites (i.e. 29.41%), two (2) hamlets (Labongou and Inacli) and individual sites in Bonkoukou. The choice of these sites is based primarily on the number of producers that they abound, in addition to the proximity of the villages and hamlets of the operators to Bonkoukou, the capital of the commune. The idea of proximity is explained by the insecurity that undermines the area and the inability to get around on motorcycles. Thus, it was decided to write on a piece of paper the name of the villages and hamlets (selected for the draw) to draw randomly, one by one, the names of the villages and hamlets that were the object of this study. The results of the implementation of this diagnostic phase of the study areas are formalized through elaborate classes which made it possible to select ten (10) villages and four (4) hamlets to derive by discretization only the five (5) villages and two (2) hamlets mentioned above.

Direct observation consisted of a visit to the study area, to assess the reality of vegetable production at the selected sites. It took place from September 20^th, 2020 to October 22^th, 2020 in the study area, in addition to a one-week stay in Filingué. As a practical phase of the operational research in the field, it took place in three stages, namely an interview phase, a questionnaire administration phase and a phase of creation and documentation of qualitative data on the sites. The interview phase enabled discussions with departmental and municipal technical services, the Municipality of Imanan and the partners working in the area. Discussions focused on cultivation techniques, the contributions of technical services and community development partners in the preservation of environmental resources in the context of market gardening. The interview also concerned the different types of training that producers benefit from to ensure the sustainability of natural resources. The administration phase of the survey questionnaire, or the collection of data on the perception of operators vis-à-vis the practices and accompanying actions and policies in the context of the development of their activities. It involved measuring the socio-economic characteristics of market gardeners (e.g. lucrative activities), working conditions, crop protection methods, the impacts of agricultural activities on natural resources and the health status of the population. On the sites, the choice of market gardeners was also made randomly. In total (Table 1), 78 market gardeners were surveyed, including 56 men (or 71.79% of those surveyed) and 22 women (or 28.21% of those surveyed).

The creation and documentation of qualitative data on the sites include photographic shots of the modes of preparation and exploitation of the plots, the irrigation and crop protection systems, the surface conditions and all projections of the impacts of the activities, agriculture on the environment. This involves having, validating, weighing and comparing data relating to the perceptions of operators with those of the reality on the ground, in particular with regard to the various impacts on environmental components and the mitigation measures that are required.

The data collected in the field through the survey of market gardeners were entered and processed with Word and Excel software. The main elements taken into account in the processing of the data are the general characteristics of the producers surveyed (e.g. the level of education) and the factors of production. These include cultivation techniques (cropping systems, irrigation, etc.), the

directory of different types of inputs and their use, as well as the different types of fences. Finally, the impacts that these cultivation techniques and the inputs used are likely to have on environmental resources (water, soil and vegetation) were analyzed. Garmin brand GPS devices and an Android phone were used, respectively, to take geographic coordinates and photographs of the sites visited.

Figure 9 presents the failings and wishes of producers to mitigate the negative impacts (or even optimize the most positive) on environmental resources. Thus, 79.49% of respondents say they need training in cultivation techniques (e.g. cropping system). According to them, it is fitting that only those in charge of the organizations of market gardeners, relatives, friends and acquaintances benefit from the training. In addition, 51.28% of respondents request external assistance (e.g. subsidies for wire mesh). Finally, 15.38% of respondents expressed their need for PPE (e.g. gloves) in order to ensure adequate protection against the effects of inputs during their application on the sites.

This study clearly shows that market gardening is more practiced by people between 31 and 50 years old (44.87% of respondents). Indeed, this fringe of the population represents more able-bodied workers and has more cultivable land. These results are slightly different from those of Muliele et al. [16] who report that producers in the gardening zone of Nkolo (Central Province of Kongo, Democratic Republic of Congo) aged between 20 and over 50 represent the greatest number. However, for more than half of the producers questioned (59.90%) are without formal education and therefore illiterate and with small proportions for the primary and secondary level. Consequently, compliance with certain standards of cultural practice (e.g. compliance with the dosage for the use of pesticides) remains very difficult. What is remarkable about the visited sites, several speculations are cultivated, including the potato which occupies the first place (100% of respondents). The results of Kagambega [17] are moderately inferior to these data. Indeed, according to the results of this author, 60% of producers cultivate potatoes on the Ouahigouya site (Burkina Faso). The difference can be explained by the sources of irrigation water supply. The main source of water supply at the Ouahigouya site is the well, while in the rural commune of Imanan, wells remain little used for boreholes and motor pumps.

Additionally, other so-called companion crops are grown (e.g. Moringa). These results are contrary to those of Seydou Oudou [18] obtained in Djiratawa (Maradi, Niger) where Moringa is cultivated by all respondents (100% of respondents). Rotation is the main cropping system for the producers surveyed with 69% sample against 26% for the pure cropping system. Most market gardeners do not have enough land to make the system of pure cultivation, or do not have enough means to develop it. The working tools available to the producers surveyed remain traditional and rudimentary. In fact, dabas, cutters, watering cans and shovels are part of the equipment that makes tillage very difficult and expends more energy. This could be a brake on the emergence of irrigation in the study area. These results corroborate those found by Mahamadou et al. [19]. Thus, producers lack modern tools to increase agricultural output. This reality on the ground would keep these producers in a state that allows them just to cover their daily needs (e.g. purchase of food).

However, if we refer to the statements of the same producers, market gardening and their agricultural choices allow them to meet many basic needs and accumulate wealth. From this point of view, these results corroborate the findings of Hassane [8] and Boubacar Oumarou [9]. Beyond the pecuniary benefits that these activities provide to operators, approximately 73% of respondents claim to be affected by pathologies (e.g. respiratory disorders and dermatological problems). Indeed, in order to garner more yields, farmers are using and abusing more and more phytosanitary products, especially unapproved ones. The investigation leads to the conclusion that the practice of market gardening in the municipality takes a certain toll on environmental resources.

When preparing the plots, a titanic amount of water is used by all producers to facilitate tillage. This would result in lowering the piezometric level of the aquifer. It is noticed that the tools used by the interviewees are archaic and contribute to an indescribable waste of water during the activities. The authors of [20] observed these facts in Algeria. This is explained by the fact that the potato is too water demanding a species especially during growth and tuberization. Considering the importance of the water resource and the capricious climatic conditions which characterize the study area (Sahel), the use of modern tools (e.g. the drip device) is necessary.

The increasing use of chemical pesticides by market gardeners has emerged as the most effective and cheapest way to control pests and increase production in a small area [21]. This anarchic use of pesticides and abuse of inorganic fertilizers thus exposing the water resource to the risk of groundwater pollution. These results join those of Mahamadou et al. [19] in the Kantché zone (Zinder region, Niger). Chemical analysis is needed to confirm the hypothesis. Also, as one producer pointed out, this misuse of inputs degrades soil fertility so that agricultural land becomes increasingly infertile (e.g. the problem of salinization; [13] ). Unlike the irrigated perimeter of Djiratawa [18], where association is the main method of cultivation, rotation constitutes the main cultivation system in Imanan. Such a system contributes to soil degradation on the sites. Currently, there is overexploitation (i.e. no fallow) of land. This has contributed to the aging of the resource by causing its degradation. In addition, the extension of cultivable areas, like the demographic growth that characterizes Niger, has greatly favored the phenomenon of runoff and therefore erosion [22]. The increase in the phenomenon of arable land has indeed contributed to massive destruction of vegetation. As Souley Yero [23] has already pointed out, in his study area, deforestation is also marked by the clearing and cultivation of forests. These facts can be explained by the fact that our study areas belong to the same part of Niger (West) where the populations have the same concern which is the increase in crop fields to face the galloping demography which undermines the country. Studies conducted by Camard and Magdelaine [24] have shown that the uncontrolled use of inputs contributes to the destruction of biodiversity in general and, in particular, vegetation. The authors of [24] define pesticides as substances that make it possible to prevent, control or eliminate organisms considered undesirable, whether they are plants, animals, etc. From this and with the uncontrolled use of these pesticides, we deduce that the vegetation is destroyed.

For 70.65% of those questioned, the protection of irrigated plots still depends on dead hedges. The renewed use has greatly contributed to the disappearance of the vegetation cover (Figure 10). As pointed out by Hassane Seyni et al. [25], the branches of thorn trees constitute for the majority of producers the means to protect their plots. The agreement of our results can be explained by the meager financial means available to most of the people surveyed. Either way, clearing, done by new producers or for suppliers of wood to renew fences, exposes the soil to the phenomena of water and wind erosion (Figure 10(a)). The consequences are, on the one hand, the generalized development of crusting beaches on the slopes and therefore favorable to runoff (Figure 10(b)), then the multiplication of large lateral gullies with torrential flows during exceptional rainfall events [26]. As for the bare soil and sheltering many potato storage pits, it remains at the mercy of erosive agents (water and wind) which move pollutants as they please (waste oils, inputs and pesticides), ravel the current landscape with of course the contribution of the practices of market gardeners. This change in surface conditions is at the origin of the development at an accelerated rate of a dynamic of quantitative and qualitative degradation of species within the plant cover of plateaus and slopes (Figure 11). As so well underlined in the Middle Niger [23], we are today inevitably witnessing the effective disappearance of plant cover. In the study area, some producers were trained in Assisted Natural Regeneration (ANR). According to Larwanou and Abasse [27], the ANR is based on existing strains where natural suckers which are selected, pruned and protected to accelerate growth contrary to the conventional practice of the peasants, which was to systematically cut off the shoots when preparing the fields. The mayor of Imanan confirmed that the Community Action Program III project

(PAC3) [10] initiated 11 pilot villages for the practice of ANR. Although practiced on a small scale, some producers use this technique to ensure the re-greening of vegetation and the protection of plant species. Recourse to rain-fed cowpea cultivation on the same plots is likely to ensure soil fertilization through the nitrogen fixing power that cowpea possesses [28].

Similarly, the drying of the branches intended for the fences, which results in, among other things, an amendment of the foliage left in the plots, has considerably impacted the practice of soil fertilization by the farmers. Since some growers deduce the uselessness of inorganic fertilizers so that they supplement humic amendments with a lot of organic manure. Finally, mulching and burning remain part of the framework for improving certain physicochemical properties of the soil.

In the rural commune of Imanan, compliance with the regulations vis-à-vis the protection of natural resources as being a common heritage is in violation by the producers surveyed. In this sense, we note the non-respect of the framework law n˚ 98-56 of December 29, 1998 relating to the management of the environment, in particular in its articles 55 and 78 [9]. Indeed, producers use natural resources (e.g. soil) in a non-rational way that tends to degrade these expensive and irreplaceable resources. These facts are also observed by Assoumane Kelé [28]. Thus, he reports that the producers surveyed use an enormous amount of inputs tending to optimize yield to the detriment of natural resources.

In addition, article 52 of the same law is not in force. Because the very intense use of pesticides degrades water quality. This remark had already been made in the gardening zone of Ngaoundere City of Cameroon [29] and elsewhere [21]. In fact, non-compliance with the Basel Convention has been observed in the study area. Indeed, the marketing of unapproved and dangerous products is done in this locality. Violation of this convention hinders the protection of environmental resources through the use of inputs not recommended for market gardening [9].

The results of our survey stipulate that to mitigate the negative impacts associated with the practice of market gardening, a number of measures must be taken. On the other hand, the application of these measures requires the full involvement of all the actors concerned by the agricultural sector. And this is for the sole purpose of rational exploitation of environmental resources. Ultimately, most of the people surveyed (79.49%) say they need training in cultivation techniques. These results remain in agreement with the study carried out by Seydou Oudou [18].